MAAs occupy a unique niche in biology. To date, only cyanobacteria, phytoplankton, and algae are known to synthesize them, and more than 570 species of marine macroalgae are thought to harbor the compounds. Their chemical structures are diverse, their light and thermal stability is excellent, and they are considered non-toxic, qualities that have long made them attractive candidates for cosmetics and pharmaceuticals. Yet their antioxidant behavior has remained surprisingly understudied, particularly in comparison with the polysaccharides, phenols, and pigments that dominate the seaweed antioxidant literature. The Jiangsu team, led by Yingying Sun, set out to close that gap by focusing on six species that are common in Chinese waters and cuisine: Bangia fuscopurpurea, Gelidium amansii, Sargassum fusiforme, Palmaria palmata, Sargassum sp., and Undaria pinnatifida.

The first hurdle was cosmetic in the most literal sense. In the researchers’ earlier work, MAA extracts from several of these algae came out stained black-red or black-green by co-extracted pigments, which muddied subsequent activity assays and complicated any practical application. Their solution was elegantly simple: wash the dried, powdered algae with anhydrous ethanol before the real extraction begins, discarding the pigment-laden supernatant. Spectrophotometric scans confirmed the wash was pulling out chlorophyll, phycobiliproteins, and beta-carotene, the compounds responsible for the unwanted color. Only then did the team extract the MAAs themselves using 25 percent methanol at 45 degrees Celsius, followed by repeated rounds of cold ethanol precipitation to strip away remaining non-target material.

The results of this pretreatment were striking. The purified extracts emerged a transparent reddish hue rather than an opaque dark sludge, and for two species the yield actually improved rather than suffered. Bangia fuscopurpurea delivered 1.5 times its previous MAA output, reaching a yield of 23.62 percent of the dried algal powder, while Gelidium amansii improved by a factor of 1.1. For the brown algae, the trade-off was less favorable: yields of Sargassum fusiforme, Sargassum sp., and Undaria pinnatifida declined significantly, suggesting that some MAAs were lost during the extra purification steps and that the protocol will need species-specific refinement. High-performance liquid chromatography coupled with mass spectrometry showed that the cleanup did not alter the underlying chemistry. The extracts were dominated by four familiar MAAs: palythine, palythenic acid, shinorine, and porphyra-334. Notably, the team reports the first detection of palythenic acid in Palmaria palmata, a compound previously known mainly from phytoplankton and a handful of other macroalgal species.

With clean extracts in hand, the antioxidant testing began. Using a Trolox-based assay, the researchers found that the total antioxidant capacity of the extracts from Bangia fuscopurpurea and Sargassum fusiforme towered over the rest, running 1.8 to 5.1 times higher than the other four species. The superoxide anion scavenging assay told a similar story. At a concentration of 50 milligrams per milliliter, the extracts from Sargassum fusiforme, Bangia fuscopurpurea, and Sargassum sp. neutralized more than 93 percent of the superoxide radicals in solution, while the remaining three species still managed above 64 percent. The half-maximal effective concentrations for the two standouts hovered around 30 milligrams per milliliter. Vitamin C, it should be said, remains the benchmark, achieving over 96 percent scavenging at a mere 0.035 milligrams per milliliter, so the MAAs are not about to displace ascorbic acid on potency alone.

But potency is not the whole story, and the authors point to a mechanistic nuance that could change the calculus. Earlier studies have shown that although porphyra-334 and shinorine score modestly in DPPH radical assays, they are remarkably effective at quenching free radicals through hydrogen atom transfer, a different chemical pathway. The relatively low concentration of active MAAs within the crude extracts may also be masking their true capability, and the researchers anticipate that further purification could substantially boost performance. There is even suggestive evidence that MAA antioxidant activity contributes to inhibiting cancer cell activity, though that frontier remains exploratory.

Perhaps the most immediately practical finding concerns browning, the enzymatic discoloration that turns a sliced apple or yam an unappetizing brown within hours and drives consumer rejection of fresh-cut produce. When the team soaked yam slices and red Fuji apple slices in dilute MAA solutions and tracked them over three days, the untreated controls browned dramatically while the treated slices stayed visibly fresh. The extracts from Bangia fuscopurpurea and Sargassum fusiforme performed best, and a component isolated from the Bangia extract via silica gel chromatography outdid them all, suppressing browning in more than 52 percent of yam and apple slices after 48 hours. That performance exceeded what has been reported for green tea extract, a standard natural anti-browning agent. The researchers speculate the effect may be linked to the impressive moisture-absorption and retention properties previously documented for Bangia MAAs, though the precise mechanism awaits further study.

Safety and formulation matter just as much as activity for any food additive, and here the mineral analysis delivered reassuring news. Inductively coupled plasma optical emission spectrometry revealed that the extracts are rich in essential macro-elements such as calcium, potassium, magnesium, sodium, and phosphorus, along with beneficial trace elements including iron, zinc, copper, and molybdenum. Critically, no harmful heavy metals, lead, cadmium, arsenic, or mercury, were detected, and copper levels sat far below the limits set by the Chinese Pharmacopoeia. The team then stress-tested the two star extracts against five common food additives over 40 days at both 25 and 48 degrees Celsius. Citric acid proved destructive, cutting absorbance by more than 23 percent for the Bangia extract and over 40 percent for the Sargassum extract by the experiment’s end, while sodium glutamate also destabilized the Bangia extract. Agar and carrageenan, by contrast, actually enhanced stability, making them natural formulation partners.

The convergence of these findings, cleaner and higher-yielding extraction, demonstrated antioxidant and anti-browning activity, a benign mineral profile, and compatibility with common food hydrocolloids, sketches a credible path from laboratory bench to grocery shelf. The authors are careful to note the limitations: yields for the brown algae need improvement, antioxidant potency trails vitamin C, and the anti-browning mechanism remains unexplained. Future work will expand the evaluation to weight loss, texture, color, and visual quality of treated produce, and will probe the health-food applications of the Sargassum fusiforme and Bangia fuscopurpurea extracts in greater depth. Still, the study marks a first on several fronts, from the mineral content analysis to the food-additive stability data, and it strengthens the case that the ocean’s humble seaweeds, already hailed as biorefineries and super plants of sustainable development, hold molecules capable of keeping our food fresher and perhaps our bodies healthier.

Subject of Research: Optimized extraction and antioxidant application of mycosporine-like amino acids from marine macroalgae

Article Title: Research on the optimization of preparation and the application analysis of antioxidant activity of mycosporine-like amino acids derived from marine macroalgae

Article References: Li, Y., Wang, J., Wang, S., Jiang, X., Shi, S., & Sun, Y. (2025). Research on the optimization of preparation and the application analysis of antioxidant activity of mycosporine-like amino acids derived from marine macroalgae. Blue Biotechnology, 2(1), Article 2. https://doi.org/10.1186/s44315-025-00023-z

Image Credits: AI Generated

DOI: 10.1186/s44315-025-00023-z

Keywords: mycosporine-like amino acids, marine macroalgae, antioxidant activity, seaweed, food preservation, anti-browning, palythine, shinorine, porphyra-334, extraction optimization, food additives, blue biotechnology

A new study published in Food Chemistry: X offers a surprisingly elegant solution, and it comes from a part of the peanut that manufacturers routinely throw away. A research team led by Yuan Gao and Mingqing Wang of Shandong Academy of Agricultural Sciences turned its attention to the peanut embryonic axis, sometimes called the peanut heart. This tiny structure, which contains the hypocotyl, radicle, and plumule and represents only about 2.5 percent of the total kernel mass, is often removed during commercial processing because of its bitter taste. While peanut skins and hulls have attracted considerable attention as sources of valuable phenolics and proanthocyanidins, the embryonic axis has remained largely unexplored territory, despite earlier reports that it contains lower levels of the major allergen mRNAs Ara h 1 and Ara h 3 and higher concentrations of minerals such as magnesium, phosphorus, potassium, calcium, iron, and zinc compared with the cotyledon.

To understand what makes the embryonic axis chemically distinctive, the researchers conducted a comprehensive comparison between the axis and the cotyledon, the fleshy tissue that constitutes the bulk of the peanut kernel and the main raw material for peanut butter. Proximate analysis revealed meaningful compositional differences. The cotyledon contained 46.90 percent fat, whereas the embryonic axis held only 39.35 percent, a reduction of more than seven percentage points. The axis also carried more crude fiber, at 8.07 percent versus 6.31 percent in the cotyledon, and more carbohydrate, at 22.7 percent versus 16.4 percent. Protein content, by contrast, showed no significant difference between the two tissues. This profile of lower fat and higher fiber immediately suggested that the axis could serve as a functional ingredient capable of improving both the nutritional profile and the physical behavior of peanut butter.

The most striking findings emerged from untargeted metabolomics performed with ultra-performance liquid chromatography coupled to tandem mass spectrometry. Using a Thermo UHPLC-Q Exactive system operating in both positive and negative electrospray ionization modes, the team identified 419 metabolites that were significantly up-regulated and 201 that were down-regulated in the embryonic axis relative to the cotyledon. Among the plant secondary metabolites driving this separation, terpenoids dominated, accounting for more than half of the differential compounds, with triterpenoids forming the largest subgroup. Of the top 25 metabolites distinguishing the two tissues, 20 were triterpenoids, and all were markedly more abundant in the embryonic axis. These included compounds with well-documented biological activities, such as beta-elemonic acid, momordicinin, and maslinic acid, which have been associated with anti-cancer and anti-inflammatory effects, along with ginsenoside I, ginsenoside Rh7, and several soyasaponins known for antioxidant and antimicrobial properties.

Armed with this chemical portrait, the researchers formulated peanut butter in which roasted, peeled peanut kernels were partially replaced by embryonic axis at substitution levels of 2.5, 5, 7.5, and 10 percent by weight. The control spread was prepared from 100 percent roasted kernels with no added salt, sugar, oil, or stabilizers, ensuring that any observed effects could be attributed to the axis itself. Proximate analysis of the finished products showed that fat content declined progressively from 51.71 percent in the control to 49.23 percent at the 10 percent substitution level, while crude fiber rose significantly from 6.73 percent to 7.43 percent and carbohydrate climbed to 16.0 percent at the highest inclusion. Protein remained essentially unchanged across all formulations, hovering between 23.7 and 23.9 percent. Because lipid oxidation begins with the substrate itself, reducing the pool of oxidizable fat inherently slows the initiation and propagation of peroxidation reactions.

Texture and rheology measurements revealed that the embryonic axis did more than simply dilute the fat. Hardness increased from 0.79 newtons in the control to 0.94 newtons at 10 percent substitution, while adhesiveness rose from 0.96 to 1.51 newton-millimeters, and springiness, gumminess, and chewiness all climbed significantly as well. Rheological testing showed that all samples behaved as pseudoplastic, shear-thinning fluids, with apparent viscosity decreasing as shear rate increased from 0.1 to 100 reciprocal seconds. The flow curves fitted the power-law model with coefficients of determination between 0.989 and 0.996, and the consistency index rose from 37.29 pascal-seconds to the power of n in the control to roughly 50 at the two highest substitution levels. The researchers attribute this firmer, more cohesive structure to two mechanisms: the reduced free oil that would otherwise act as a lubricant, and the long molecular chains of dietary fiber, which intertwine into a three-dimensional network that binds oil and restricts its movement through the matrix.

The antioxidant evidence was equally compelling. Radical scavenging assays showed that spreads containing 7.5 and 10 percent embryonic axis displayed significantly higher activity against both DPPH and ABTS free radicals than the control, and the 10 percent formulation outperformed the 2.5 and 5 percent versions in the DPPH assay. Spearman correlation analysis confirmed that fiber content was strongly and positively associated with radical scavenging, with correlation coefficients of 0.903 for DPPH and 0.888 for ABTS. The enriched triterpenoid fraction likely contributed as well, since compounds such as maslinic acid, ginsenosides, and soyasaponins have demonstrated free radical neutralization and shelf-life extension in other food systems. Although roasting can partially degrade certain heat-labile saponins, the authors note that degradation is compound-specific and unlikely to have eliminated the overall antioxidant capacity of the enriched spreads.

Storage performance under accelerated conditions provided the decisive test. Samples packed in PET jars were held at 37 degrees Celsius for four weeks and monitored for oil separation and peroxide value. At the outset, all axis-fortified spreads showed markedly lower oil separation than the control, and a clear dose-dependent relationship emerged, with higher substitution levels corresponding to less oil loss over time. The researchers suggest that surface-active triterpenoid saponins may lower interfacial tension and form stable viscoelastic films that inhibit the coalescence and migration of oil droplets, while the denser fiber network physically entraps liquid oil. Peroxide values told a similar story: the control started at 5.25 millimoles per kilogram and climbed to 7.78 by week four, whereas the fortified spreads began between 3.28 and 4.77 and reached only 6.7 to 7.0 after the same period, demonstrating that the axis genuinely retarded lipid oxidation rather than merely masking its symptoms.

Crucially, none of these functional benefits came at the cost of appearance or palatability. Colorimetric analysis in the CIELab system showed no significant changes in brightness, redness, or yellowness across formulations, and the overall color difference relative to the control remained low, between 0.92 and 1.54, well within the range considered visually acceptable. A semi-trained sensory panel of twelve regular peanut butter consumers rated all spreads on a nine-point scale covering appearance, flavor, consistency, taste, spreadability, and overall acceptability. The 2.5 percent substitution earned the highest overall score of 8.0, compared with 7.4 for the control, and also received the best flavor rating at 7.8. Scores declined modestly at higher inclusion levels, likely because triterpenoid saponins impart a characteristic bitterness, but even the 10 percent formulation matched the control at 7.4, indicating that the axis never pushed the product beyond consumer tolerance.

The implications extend well beyond a single spread. The study demonstrates that a bitter, discarded fraction of the peanut, available essentially for free as a processing by-product, can simultaneously reduce fat, boost fiber, enhance antioxidant activity, suppress oil separation, and slow rancidity, all while preserving the clean-label, single-ingredient character that modern shoppers increasingly demand. The authors caution that their metabolomics results are semi-quantitative and based on limited biological replicates, so targeted absolute quantification will be needed to confirm the triterpenoid findings, and sensory testing was performed only at the initial time point rather than after storage. Future work may explore synergies between the embryonic axis and other natural antioxidants and extend the approach to other oil-rich food systems. For now, the humble peanut heart, once destined for the waste stream, has earned a place at the center of a smarter, more sustainable peanut butter.

Subject of Research: Use of peanut embryonic axis as a natural functional ingredient to improve the texture and oxidative stability of peanut butter

Article Title: Composition characterization of peanut embryonic axis and its application in peanut butter: Effects on texture and oxidative stability

Article References: Gao, Y., Fu, B., Wu, J., Yu, L., Bi, J., Song, Y., Wang, L., Jiang, C., & Wang, M. (2026). Composition characterization of peanut embryonic axis and its application in peanut butter: Effects on texture and oxidative stability. Food Chemistry: X, 39, Article 104532. https://doi.org/10.1016/j.fochx.2026.104532

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104532

Keywords: peanut butter, peanut embryonic axis, lipid oxidation, triterpenoids, dietary fiber, natural antioxidants, oxidative stability, oil separation, peroxide value, food by-product valorization, rheology, clean-label foods

The research team, led by Charlène Sirvins, Pascale Goupy and Claire Dufour of INRAE in France, focused on four abundant plant phenolic compounds: chlorogenic acid, caffeic acid, ferulic acid and hydroxytyrosol, the principal phenolic aglycone of olives. These molecules are ubiquitous in the human diet, found in coffee, fruits, cereals, olive oil and red wine, and previous work had shown that plant extracts rich in such compounds can reduce volatile N-nitrosamines in dry-cured bacon and sausages. What remained unclear was precisely how each phenolic structure intercepts the nitrosation reaction, and whether the standard laboratory test used to measure this protective capacity was telling the whole truth.

To find out, the team built a simplified cured meat model built around N-acetyltryptophan, a tryptophan derivative chosen because it carries a useful light-absorbing chromophore and retains the amide bond found in covalently linked amino acids within real proteins. The model contained nitrite at 120 parts per million, matching the newly reduced industrial maximum, plus 30 micromolar of non-heme iron, a pro-oxidant naturally present in meat. The researchers then tracked the formation of N-acetyl-N-nitrosotryptophan, a model secondary N-nitrosamine, over time at two pH values: pH 5, simulating meat processing and the early stage of gastric digestion, and pH 2.5, representing the harshly acidic final stage of digestion in the stomach. Using ultra-high-performance liquid chromatography coupled to diode-array detection and ion-trap mass spectrometry, they followed not only the target nitrosamine but dozens of newly formed reaction products.

The baseline behavior of the model system was itself revealing. At pH 2.5, nitrosation of the tryptophan derivative was rapid, reaching a maximum conversion of 17.2 percent within 45 minutes, but the resulting nitrosamine proved unstable and reverted quantitatively back to its parent amine within hours through acid-catalyzed denitrosation. At pH 5, the reaction was slower and the product more persistent, with a maximum conversion of 3.6 percent. This matters because nitrosated amino acids and peptides formed in the acidic stomach could pass into the near-neutral environment of the duodenum, around pH 6.5, where they would be stabilized before intestinal absorption. In other words, the stomach is not merely a hostile environment for nitrosamines; it is a potential factory for them, and whatever survives the journey onward is the more dangerous cargo.

When the phenolic compounds entered the picture, the differences between them were striking. Caffeic acid and ferulic acid, the two unesterified hydroxycinnamic acids, were the champions, suppressing nitrosation by 85 percent within 15 minutes at pH 2.5 and achieving complete inhibition after 105 minutes. At pH 5, caffeic acid still held inhibition between 66 and 77 percent over the reaction period. Chlorogenic acid, which is simply caffeic acid esterified with quinic acid, performed markedly worse, managing only 24 percent inhibition at pH 2.5 and 16 to 28 percent at pH 5. Hydroxytyrosol fell in between. The lesson was clear and chemically elegant: the same reactive core can behave very differently depending on whether a bulky ester group blocks access to it.

The mass spectrometric detective work revealed two fundamentally different protection strategies at play. For chlorogenic acid and hydroxytyrosol, both bearing a catechol group, the story begins with nitrite-induced oxidation. Nitrite strips electrons from the catechol ring, generating a reactive quinone intermediate. That quinone can then dimerize with another phenol molecule, undergo nitration to form nitrochlorogenic acid or nitrohydroxytyrosol, or be attacked by nucleophiles. Each of these pathways consumes multiple nitrite ions; nitration of a single catechol unit alone requires three. Hydroxytyrosol proved especially voracious, scavenging at least three nitrite ions per molecule at both pH values, with nitrohydroxytyrosol emerging as its dominant product and a rich menagerie of dimers, trimers and covalent adducts with the tryptophan derivative accumulating alongside.

Caffeic and ferulic acid took an entirely different route. Instead of being oxidized, their propenoic acid side chains were directly attacked by the nitrosonium ion, the very electrophile that would otherwise nitrosate the amine. This creates a resonance-stabilized nitroso cation on the phenolic molecule, and here comes the surprise: the tryptophan derivative, present in threefold excess, turned out to be a stronger nucleophile than water or nitrite, and it covalently latched onto that cation. The result was a family of acetaldehyde oxime adducts, some still bearing the nitrosated amine, others stripped of it. In effect, caffeic and ferulic acid were acting as decoys, diverting the nitrosating machinery and then capturing the amine target itself before it could be converted into a free, mobile nitrosamine.

That capture, however, exposed a hidden flaw in the standard assay. Because the covalently bound tryptophan derivative escaped quantification, the apparent disappearance of the free amine inflated the measured antinitrosating capacity of caffeic and ferulic acid. When the researchers recalculated protection based on the number of nitrite ions actually scavenged by the five major end products of each reaction, the ranking shifted. Hydroxytyrosol emerged as superior to chlorogenic acid at pH 5, while the two catechol compounds matched each other at pH 2.5, and the unesterified hydroxycinnamic acids, despite their dazzling performance in the simple test, actually quench less nitrite per molecule. The team showed that the same bias applies to flavonoids such as rutin, quercetin and epicatechin studied previously, meaning the corrected framework offers a more honest yardstick for screening plant extracts intended for cured meat reformulation.

The practical implications reach beyond the laboratory beaker. Phenolic-rich extracts from olive, grape and rosemary have already been shown to lower volatile N-nitrosamines in sausages and bacon, and olive leaf extract rich in oleuropein, an acylated hydroxytyrosol derivative, has been tested in ripened industrial sausages as a partial nitrite replacement. The new mechanistic map explains why such extracts work and which structural features matter most: catechol groups that surrender electrons to nitrite, and free propenoic chains that intercept the nitrosonium ion directly. It also raises a nutritional angle worth savoring. Eating plant foods rich in these phenols alongside cured meats, or indeed alongside the dietary nitrate from leafy vegetables that fuels endogenous nitrite production in the stomach, could dampen the nitrosation of amino acids during digestion itself. There remain open questions, notably the toxicological significance of the structurally modified peptides released when phenols bind covalently to food proteins, but the study firmly establishes that the chemistry of protection is as intricate as the chemistry of harm, and that understanding both is the surest path to a safer plate.

Subject of Research: Inhibition of N-nitrosamine formation by plant phenolic compounds in cured meat and gastric digestion models

Article Title: The antinitrosating capacity of hydroxycinnamic acids and hydroxytyrosol in a cured meat model unraveled through structural and kinetic investigations

Article References: The antinitrosating capacity of hydroxycinnamic acids and hydroxytyrosol in a cured meat model unraveled through structural and kinetic investigations. (n.d.). https://doi.org/10.1016/j.crfs.2026.101581

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101581

Keywords: N-nitrosamines, nitrite, cured meat, polyphenols, hydroxytyrosol, caffeic acid, ferulic acid, chlorogenic acid, food chemistry, nitrosation, gastric digestion, food safety

The research team began with a byproduct that most juice factories discard by the ton: orange peel. Using an 80 percent ethanol extraction followed by purification on an AB-8 resin column, the researchers obtained a flavonoid-rich extract that was then profiled by targeted UPLC-ESI-QQQ-MS/MS against a panel of 46 flavonoids. Quantifiable signals emerged for 35 compounds, with kaempferide dominating at roughly 78,252 nanograms per gram and neohesperidin close behind at about 43,642 nanograms per gram. These two flavonoids became the structural representatives for the molecular modeling that followed, and their abundance helped explain why the extract showed the strong antimicrobial and antifungal reputation that citrus peel has accumulated in the literature.

The gel itself was assembled through heat. Bovine serum albumin, a 66-kilodalton protein, was dissolved in dilute salt solution, combined with curdlan—a bioactive polysaccharide of 300 to 500 glucose units—and held overnight at 4 degrees Celsius before being heated to 81 degrees for ten minutes to trigger irreversible gelation. The flavonoid extract was added at three concentrations, 5, 7, and 9 milligrams per milliliter, producing gels labeled BSA-Cn-Fs-5, BSA-Cn-Fs-7, and BSA-Cn-Fs-9. Food-grade ethanol in the final mixture never exceeded 5 percent, keeping the formulation within the bounds of what a food application could tolerate. The resulting heat-set gels looked and behaved like pliable orange-tinted matrices, semi-spherical in microstructure and noticeably more compact once the flavonoids were woven in.

The central analytical question was how, exactly, the flavonoids were held inside the gel. A battery of multispectral techniques converged on a single answer: non-covalent bonding, dominated by hydrogen bonds. Fourier transform infrared spectroscopy showed the hydroxyl stretching band of the protein–polysaccharide network shifting from 3323.78 to 3278.38 reciprocal centimeters after flavonoid loading, a classic fingerprint of hydrogen-bond formation. Ultraviolet–visible spectra retained the flavonoid signature near 330 nanometers inside the gel, and intrinsic fluorescence of the albumin was quenched in a concentration-dependent manner, reaching 97.44 percent quenching at the highest extract loading, with the emission peak shifting dramatically from 341 to 420 nanometers—evidence that the aromatic chromophores of the protein had entered a genuinely altered chemical environment.

Structural and thermal analyses reinforced the picture. X-ray diffraction revealed that the composite gels were largely amorphous, with reduced molecular ordering after flavonoid incorporation, a transition the authors note may enhance bioaccessibility and sustain flavonoid activity over time. Differential scanning calorimetry showed the loaded gel undergoing major transitions at 230.12 and 315.01 degrees Celsius, higher than the corresponding peaks of curdlan alone, consistent with non-covalent stabilization of the network. X-ray photoelectron spectroscopy documented an increase in the oxygen signal and a decrease in the carbon signal after loading, matching the oxygen-rich chemistry of flavonoid hydroxyl groups joining the matrix. Molecular docking of kaempferide and neohesperidin into albumin identified plausible contacts with residues including Trp213, Arg217, and Ser343, with calculated interaction energies of −1.91 and −1.98 kilocalories per mole respectively—modest values that the authors interpret qualitatively as support for the spectroscopic evidence rather than as measured binding strengths.

Functionally, the gels behaved like reservoirs rather than single-dose dispensers. Over 24 hours in buffered solution at body temperature, cumulative flavonoid release reached 65.60 percent for the lowest loading, 67.91 percent for the middle formulation, and 72.91 percent for BSA-Cn-Fs-9, with a marked acceleration around the ten-to-twelve-hour mark followed by continued slow release. Antioxidant capacity tracked the loading level: DPPH radical scavenging climbed from 25.3 percent for the unloaded gel to 40.3 percent for BSA-Cn-Fs-9, while ABTS scavenging rose from 81.43 to 93.73 percent. The authors are careful to state that BSA-Cn-Fs-9 was the best performer within the tested range rather than a statistically optimized global maximum, an honest caveat that distinguishes this work from looser claims in the food-preservation literature.

The antimicrobial results were equally concrete. In agar diffusion assays, the loaded gels produced inhibition zones that widened with flavonoid concentration against four significant foodborne and spoilage bacteria—Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes. Listeria proved the most sensitive, yielding a 16-millimeter zone around the highest-loading gel compared with 8.7 millimeters for the unloaded control. Against two spoilage fungi, Penicillium expansum and Aspergillus westerdijkiae, the top formulation inhibited growth by up to 33.33 percent and 57.44 percent respectively after seven days, meaning the flavonoid integration boosted the antimicrobial activity of the base gel by as much as 36 percent. Flavonoids are thought to work by disrupting cytoplasmic membrane permeability and causing intracellular leakage, mechanisms well documented in prior citrus extract studies.

The decisive test came in a refrigerated chicken model. Fresh chicken breast portions were marinated with distilled water, the unloaded gel, or BSA-Cn-Fs-9, then stored at 4 degrees Celsius and sampled at days 0, 3, 6, 9, and 12. Control samples climbed from 3.21 to 7.82 log10 colony-forming units over the storage period, crossing freshness limits, while the flavonoid-loaded gel held total counts to 5.94 log10—within the hygiene standard for fresh poultry. Pathogen-specific counts told the same story: Bacillus cereus fell from 6.23 to 4.11 log10 and E. coli from 6.11 to 3.98 log10 under the loaded gel, with parallel suppression of Listeria and Staphylococcus. Thiobarbituric acid reactive substances, the standard marker of lipid oxidation, stayed significantly lower in treated samples, and pH rose only from 5.73 to 6.58 compared with 6.02 to 7.24 in untreated controls, reflecting the extract’s acidity and its inhibition of the alkaline nitrogen compounds that accompany meat deterioration.

What makes the study notable is the division of labor inside the gel. Curdlan contributes its own documented antifungal, immunomodulatory, and antibacterial activities, and its helix-reorganizing gelation behavior; albumin supplies heat-set gelation, antioxidant amino acid residues, and binding sites for polyphenols. Together they solve a problem that has long limited citrus flavonoids in food applications: their sensitivity to light, oxygen, metal ions, pH shifts, and heat. By physically embedding the extract in a protein–polysaccharide network held together by hydrogen bonds and hydrophobic contacts, the matrix shields the compounds while metering them out gradually—precisely the release behavior a preservative needs during a multi-day shelf life.

The authors stop well short of declaring a commercial product. Release testing was conducted only at neutral pH, no antibiotic positive control was included in the antimicrobial assays, and the docking energies were too small to interpret thermodynamically. Direct marination with a bovine-serum-albumin-containing gel also raises sensory, allergen-labeling, regulatory, and clean-label questions that the proof-of-concept model does not address. The research group’s roadmap is explicit: quantify individual flavonoids against authentic standards, optimize loading and gel composition, test release under food-relevant pH conditions, include reference antimicrobials, and reformulate the system as an edible coating or active-packaging component rather than a marinade. Even so, the core demonstration stands—waste orange peel, two edible biopolymers, and gentle heat produced a dual-action preservative that measurably slowed microbial growth, restrained oxidation, and kept refrigerated chicken within freshness limits for twelve days, a result that suggests the next generation of natural food preservatives may come less from novel chemistry than from clever engineering of familiar molecules.

Subject of Research: A dual-component curdlan and bovine serum albumin gel loaded with orange peel flavonoid extract for antimicrobial and antioxidant preservation of refrigerated chicken breast

Article Title: Enhancing the preservation of chicken breast using a curdlan/BSA gel interacted with citrus flavonoids: Interaction mode and dual-component protection

Article References: Enhancing the preservation of chicken breast using a curdlan/BSA gel interacted with citrus flavonoids: Interaction mode and dual-component protection. (n.d.). https://doi.org/10.1016/j.fochx.2026.104426

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104426

Keywords: orange peel flavonoids, curdlan gel, bovine serum albumin, chicken breast preservation, natural food preservatives, hydrogen bonding, antimicrobial activity, antioxidant activity, controlled release, lipid oxidation, food spoilage, heat-set gel

The findings matter because lipid oxidation is one of the principal engines of food waste worldwide. When oxygen attacks the unsaturated fatty acids in oils, nuts and other lipid-containing products, it generates peroxides, aldehydes and off-flavours that render food unpalatable and, in some cases, unsafe. Food loss on this scale ripples outward, placing pressure on natural resources, raising energy consumption for distribution and storage, and driving up prices in ways that undermine food security. The global antioxidant market, valued at roughly 4.6 billion dollars in 2022 and projected to reach 7.6 billion dollars by 2032, is built largely on synthetic compounds such as BHT, BHA and TBHQ, all derived from non-renewable petrochemical feedstocks. These additives persist in the environment because of their low degradability, and their accumulating presence in processed foods has raised concerns about cumulative consumer exposure.

Essential oils offer an alternative that aligns with what the researchers describe as the e3 concept: energy efficiency, environmental sustainability and the recovery of natural additives. Unlike synthetic antioxidants, they are biodegradable, can be produced from intensively cultivated aromatic crops rather than wild harvesting, and require fewer energy inputs and no organic solvents when obtained by hydrodistillation. In the study, leaves of both species were harvested in April 2025 at the peak of flowering from the university’s experimental field in Córdoba, dried at 25 degrees Celsius, and subjected to hydrodistillation in a Clevenger-type apparatus for 60 minutes. The resulting oils were obtained in yields of 1.78 percent for Lippia turbinata and 1.96 percent for Minthostachys mollis, then analysed by gas chromatography coupled with mass spectrometry.

The chemical portraits of the two oils differ markedly. Lippia turbinata essential oil is dominated by thujone at 67.38 percent of the total composition, followed by beta-pinene at 8.52 percent and limonene at 6.51 percent, with these three compounds accounting for more than 82 percent of the oil. Minthostachys mollis oil, by contrast, is built around menthone at 51.83 percent, pulegone at 31.78 percent and isomenthone at 3.23 percent, together representing nearly 87 percent of the mixture. Neither oil is rich in the phenolic terpenes, such as carvacrol or thymol, that are conventionally associated with strong antioxidant behaviour. This makes the performance of both oils all the more intriguing, because their principal constituents act through a different and complementary antioxidant mechanism.

Phenolic antioxidants function as chain-breaking antioxidants: they donate a hydrogen atom to lipid radicals and peroxidised lipid radicals, halting the propagation of the auto-oxidation cascade. Non-phenolic terpenes such as thujone, pinene, menthone and pulegone operate as termination-enhancing antioxidants. These molecules oxidise alongside the lipids themselves, generating relatively stable radical species that pair rapidly with other radicals to form non-reactive adducts, thereby accelerating the termination reactions that remove highly reactive intermediates from the system. In the DPPH free radical scavenging assay, Minthostachys mollis oil inhibited 34.49 percent of the radical while Lippia turbinata inhibited 5.37 percent, and both oils showed total phenolic contents of roughly 8.5 to 9.1 micrograms per millilitre of gallic acid equivalents. The team cautions that such indirect tests correlate poorly with real performance in foods, partly because the polar DPPH radical interacts inefficiently with hydrophobic terpenes, which is precisely why the researchers pushed on to direct oxidation experiments in an actual food matrix.

Before testing antioxidant power, the team examined how well the oils withstand heat, since an antioxidant that decomposes during storage or processing loses its value. Aliquots of each oil were held at 60 degrees Celsius for 28 days in sealed vials, with their volatile profiles captured by solid-phase micro-extraction and analysed at five time points. Principal component analysis revealed contrasting patterns of change. The composition of Lippia turbinata oil shifted gradually and continuously across the thermal treatment: the relative abundance of thujone rose over time, not because the compound was being formed, but because less stable, higher-boiling terpenes degraded around it, while limonene and beta-pinene progressively declined as they oxidised into derivatives such as carveol and terpinen-4-ol. Minthostachys mollis oil behaved differently, with most of its compositional change occurring at the very beginning of the heat exposure. Pulegone, which contains a double bond, was progressively converted to the saturated ketone menthone, a transformation that reduced the pulegone-to-menthone ratio used by the group as an indicator of antioxidant potential. Crucially, however, neither pattern of change undermined the protective performance of the oils in the subsequent oxidation tests.

For the direct assay, the researchers fortified antioxidant-free commercial sunflower oil, which contains between 48 and 74 percent oxidation-prone linoleic acid, with 0.02 percent by weight of each essential oil, or with BHT at the equivalent of 200 parts per million, the maximum permitted in food. Samples were stored at 60 degrees Celsius for 28 days and monitored through an unusually comprehensive battery of indicators: conjugated dienes, peroxide value and anisidine value as chemical markers of primary and secondary oxidation; the composite TOTOX and INTOX values that integrate both stages; and the volatile aldehydes hexanal, (Z)-2-heptenal, (E,Z)-2,4-decadienal and (E,E)-2,4-decadienal, which arise from the fragmentation of oxidised linoleic acid and are directly responsible for rancid off-odours. By day 28, untreated oil showed dramatically higher values across nearly every indicator, while oils protected by the two essential oils recorded lower peroxide and anisidine values than even the BHT-treated samples, with Minthostachys mollis delivering the strongest protection overall.

Linear regression models fitted to the oxidation trajectories quantified the advantage with unusual precision. Using a peroxide value of 10 milliequivalents of oxygen per kilogram of oil as the regulatory shelf-life limit, unprotected sunflower oil reached the threshold in just 0.83 days. BHT extended this to 3.29 days, Lippia turbinata oil to 3.60 days, and Minthostachys mollis oil to 4.59 days, corresponding to shelf-life extensions of 3.92, 4.31 and 5.48 times the control. When shelf life was instead defined by a TOTOX value of 24, which better reflects the flavour-relevant secondary oxidation that makes oil unsellable, the essential oils again outperformed BHT, extending shelf life 3.60 and 4.23 times respectively compared with 3.36 times for the synthetic additive. Principal component analysis of all chemical and volatile indicators together explained 99.6 percent of the variability and placed the two essential-oil treatments closest together at the low-oxidation end of the spectrum, ahead of BHT.

The authors also address safety, an inevitable question for oils containing thujone and pulegone, both of which are regulated monoterpenes. Under European Union Regulation 1334/2008, pulegone is capped at 250 milligrams per kilogram in the strictest food category, and the tolerable daily intake is set at 0.1 milligrams per kilogram of body weight. At the 0.02 percent application rate used in the study, oil fortified with Minthostachys mollis contains roughly 63.56 milligrams of pulegone per kilogram, well below the European limit, and a 70-kilogram person would need to consume more than 100 grams of the oil daily to exceed the tolerable intake. Thujone from aromatic plants faces no food restrictions under the same regulation, and although a preliminary acceptable daily intake of 0.11 milligrams per kilogram has been proposed, the fortification level used here would require a person to consume nearly 50 grams of oil per day to approach that threshold, an implausible quantity for normal dietary habits.

The researchers conclude that Lippia turbinata and Minthostachys mollis essential oils demonstrate thermal stability that does not compromise their antioxidant activity, and a level of protection approaching or exceeding that of BHT under accelerated conditions. Both species are well suited to intensive cultivation in central Argentina, offering a renewable, biodegradable supply chain for natural antioxidants and a route away from extractive wild harvesting. The team emphasises that further work is needed across more complex food matrices, differing in moisture, polarity and sensory requirements, and in combination with different packaging systems, before industrial adoption can be fully realised. Still, the message is striking: two fragrant herbs from the Córdoba hills may help the food industry preserve freshness with molecules that return harmlessly to the biosphere rather than accumulating in it.

Subject of Research: Thermal stability and antioxidant performance of Lippia turbinata and Minthostachys mollis essential oils as renewable natural antioxidants in sunflower oil

Article Title: Thermal stability, and chemical and volatile oxidation indicators from essential oils of Lippia turbinata and Minthostachys mollis as potential natural antioxidants from renewable sources

Article References: Juncos, N. S., Navarro, B. D. V., Corradi, M. P., & Olmedo, R. H. (2026). Thermal stability, and chemical and volatile oxidation indicators from essential oils of Lippia turbinata and Minthostachys mollis as potential natural antioxidants from renewable sources. Discover Green Chemistry, 1(1), Article 20. https://doi.org/10.1007/s44509-026-00023-1

Image Credits: AI Generated

DOI: 10.1007/s44509-026-00023-1

Keywords: essential oils, natural antioxidants, lipid oxidation, Lippia turbinata, Minthostachys mollis, BHT, shelf life, thermal stability, sunflower oil, green chemistry, Thermal, stability

The research, led by Muh Ali Arsyad and colleagues at Politeknik Pertanian Negeri Pangkajene Kepulauan in Indonesia, examined freeze-dried aqueous leaf extracts of kenikir (Cosmos caudatus) and binahong (Anredera cordifolia), two edible plants widely available across tropical Southeast Asia and traditionally valued in folk medicine. Both plants are rich in phenolic compounds, and because the extraction uses nothing but water as the solvent, the resulting powders avoid the residues and sustainability problems associated with organic solvent extraction. That combination of bioactivity, green processing, and ready dispersibility in food matrices made them ideal candidates for a dual task: strengthening the gel network of sardine surimi and protecting its fragile lipids from oxidation.

The problem the researchers set out to solve is rooted in the biochemistry of dark-fleshed fish. Sardine muscle contains high levels of hemoproteins such as myoglobin and hemoglobin, along with abundant polyunsaturated fatty acids that are exquisitely vulnerable to peroxidation. During thermal processing, lipid oxidation generates reactive aldehydes and radicals that attack myofibrillar proteins, interfering with the protein–protein interactions needed to build a cohesive three-dimensional gel network. The result is surimi with lower gel strength, reduced storage stability, and faster quality deterioration than products made from white-fleshed species. Polyphenols offer a potential way out, because they can both quench oxidation chains and engage proteins through hydrogen bonding, hydrophobic interactions, and covalent cross-linking — modifying protein conformation in ways that favor network formation rather than degradation.

To prepare the extracts, the team dried fresh leaves at 25 to 40 degrees Celsius in a cold-air dryer for 48 hours, ground and sieved them to a fine powder, then stirred 50 grams of powder into 500 milliliters of distilled water for an hour. After centrifugation, filtration, freezing, and freeze-drying, they had two additive powders ready for testing. Chemical characterization revealed a decisive difference between the two plants. Binahong leaf extract, or BLE, delivered a total phenolic content of 209.54 milligrams of gallic acid equivalents per gram of dry extract, roughly 1.75 times the 120.00 milligrams measured for kenikir leaf extract, or KLE. Antioxidant assays painted the same picture across four complementary mechanisms. BLE scavenged ABTS radicals at 55.49 micromoles of Trolox equivalents per gram versus 32.31 for KLE, and DPPH radicals at 47.17 versus 25.12. Its ferric reducing antioxidant power was 64.66 compared with 36.41 micromoles of Trolox equivalents per gram, and its metal chelating activity — critical because iron ions catalyze the Fenton reactions that drive lipid oxidation in fish muscle — reached 10.78 micromoles of EDTA equivalents per gram, more than three times the KLE value.

With the extracts characterized, the researchers chopped frozen sardine surimi with 2.5 percent salt to solubilize myofibrillar proteins, then added BLE or KLE at concentrations ranging from 0.05 to 0.30 percent by weight. The pastes were encased, set at 40 degrees Celsius for 30 minutes, cooked at 90 degrees Celsius for 20 minutes, and chilled. Breaking force and deformation — the mechanical hallmarks of gel strength and elasticity — followed a clear dose-dependent pattern with an optimum. Control gels broke at roughly 56.6 grams of force, but BLE at 0.20 percent pushed that figure to about 73.5 grams, a peak that fell away again at higher doses. KLE required more: its optimum arrived at 0.25 percent, with a breaking force near 67.9 grams. Deformation followed the same shape, peaking at about 1.4 millimeters for BLE-0.2 and 1.3 millimeters for KLE-0.25. Expressible moisture, a measure of how readily water escapes the gel under pressure, dropped from around 35 percent in the control to 23 percent at the BLE optimum and 24 percent at the KLE optimum, evidence that both extracts produced tighter matrices that immobilized water more effectively. Whiteness, importantly, was unaffected across the entire dosing range — a practical advantage for consumer acceptance, since the aqueous extraction leaves chlorophyll behind and the low doses contribute negligible color.

Texture profile analysis at the selected working concentrations confirmed these mechanical gains. Hardness rose from 651.70 grams in the control to 737.44 grams with 0.20 percent BLE, the highest value recorded, while 0.25 percent KLE produced an intermediate 701.10 grams. Springiness climbed from 0.66 centimeters in the control to 0.86 centimeters with BLE-0.2, and gumminess and chewiness rose in parallel, reaching 221.89 grams and 129.78 gram-centimeters respectively. Cohesiveness remained statistically unchanged, indicating that the extracts altered the strength and malleability of the gels rather than their internal bonding ratios. Beyond the optimal doses, all parameters declined toward control values, a signature of over-crosslinking: once protein binding sites approach saturation, excess polyphenols promote aggregation that disrupts the homogeneity of the gel network and weakens its mechanical performance.

The molecular basis for these effects emerged from Fourier transform infrared attenuated total reflection spectroscopy. The addition of BLE and KLE produced no new chemical bands, but it shifted and reshaped existing ones. Bands in the 3200 to 3400 per centimeter region, associated with amide A and overlapping hydroxyl stretching, shifted slightly to lower wavenumbers, indicating strengthened hydrogen bonding between phenolic hydroxyl groups and the carbonyl and amine groups of myofibrillar proteins. The amide I band near 1656 per centimeters held its position but changed in relative intensity, and the amide II band near 1544 per centimeters remained stable, showing that the peptide backbone was not chemically damaged — the extracts acted as modulators of intermolecular interactions rather than denaturants. Meanwhile, increased intensity of carbon–oxygen stretching bands in the 1000 to 1100 per centimeter range signaled phenolic groups integrated into the protein matrix, consistent with oxidation of phenolics into quinones that form covalent cross-links with nucleophilic residues such as lysine and cysteine during heating.

Deconvolution of the amide I band revealed the conformational story behind the improved textures. The control gel contained 54.79 percent beta-sheet, 24.96 percent alpha-helix, 9.66 percent random coil, and 10.59 percent beta-turn. The KLE-treated gel shifted modestly toward alpha-helix content, but the BLE-treated gel showed the most pronounced transformation: beta-sheet content rose to 59.18 percent, while alpha-helix and random coil fell to 22.33 and 7.38 percent respectively. The conversion of alpha-helical domains into beta-sheet conformations is a hallmark of thermal myosin unfolding and aggregation, and it exposes reactive residues that drive intermolecular association. The elevated beta-sheet fraction in the BLE gel therefore reflects a higher degree of protein–protein organization, stabilized by extensive hydrogen bonding and regulated by the polyphenols. This structural rearrangement correlated directly with function. Dynamic rheology, monitoring the elastic modulus during heating from 20 to 90 degrees Celsius, showed that the BLE gel developed the highest storage modulus during the sharp gelation phase between roughly 50 and 70 degrees Celsius, where myosin heads denature and reactive groups drive aggregate formation. Scanning electron microscopy closed the loop visually: while the control gel displayed a rough, poorly organized matrix with large, uneven pores, the BLE gel exhibited a dense, continuous, homogeneous network with small, uniformly distributed cavities — a microstructure that stores elastic energy efficiently and traps water within microcapillary spaces.

The antioxidant payoff emerged during refrigerated storage. Over twelve days at 4 degrees Celsius, peroxide values and thiobarbituric acid-reactive substances rose in all samples, but the control gels showed significantly higher oxidation at days 4 and 8, reflecting the classic progression from primary lipid hydroperoxides to secondary products such as malondialdehyde. Gels containing BLE suppressed both indices most effectively, a result the researchers attribute to a combination of intrinsic radical scavenging, metal chelation that curbs Fenton chemistry, and a denser gel matrix that physically limits oxygen diffusion. By preserving myofibrillar proteins from reactive aldehydes, BLE also protected the structural integrity that underpins gel texture, suggesting the additive improves both immediate quality and shelf life.

Taken together, the study delivers a unified molecular mechanism: polyphenols from water-extracted tropical leaves strengthen sardine surimi gels through reinforced hydrogen bonding and controlled covalent cross-linking, driving a favorable beta-sheet transition that builds a tighter, more elastic network while simultaneously shielding the product from oxidative decay. Binahong leaf extract proved the more potent additive, achieving maximum effect at 0.20 percent versus 0.25 percent for kenikir, mirroring its higher phenolic content and antioxidant capacity. For an industry seeking to upgrade abundant but underutilized dark-fleshed pelagic fish into value-added surimi products, the findings point toward additives that are effective, colorless at working doses, and produced with nothing more exotic than water — a genuinely green chemistry recipe for better seafood.

Bacillus cereus is one of nature’s most resilient opportunists. A Gram-positive, rod-shaped bacterium that lives in soil, dust and on plant surfaces, it slips easily into raw milk during collection and processing. Its true weapon is the endospore, a dormant, tough-coated structure that shrugs off boiling, pasteurization and many chemical sanitizers. When conditions improve — in a carton of chilled milk, a vat of reconstituted powdered milk, or a damp corner of a processing line — the spores germinate into actively dividing cells. Some strains produce cereulide, a heat-stable toxin that causes vomiting and survives cooking; others secrete enterotoxins that trigger diarrheal illness. The bacterium also builds biofilms, slimy microbial fortresses on stainless steel and rubber seals that continuously seed contamination into passing products. To make matters worse, the Isfahan team’s survey of one hundred B. cereus isolates recovered from various food sources revealed alarming resistance profiles, with 97 percent of the isolates resistant to gentamicin — the highest resistance recorded among the antibiotics tested — underscoring why alternatives are urgently needed.

The answer the researchers found is elegantly simple: a bigger, faster hunter. CM1 belongs to the class Caudoviricetes, the enormous group of tailed, double-stranded DNA bacteriophages that dominate the oceans, soils and, increasingly, food laboratories. Under transmission electron microscopy, the phage revealed classic tailed-phage architecture: an icosahedral protein head measuring 48 ± 2 nanometers in diameter, attached to a slender tail 142 ± 3 nanometers long. In tailed phages, the tail is more than an appendage; it is a molecular syringe and lock-pick in one. Its fiber proteins recognize specific receptors on the bacterial surface, and once a secure grip is established, the phage drives an internal channel through the cell wall and injects its genome, effectively turning the bacterium into a virus factory. The dimensions and morphology captured by the Iranian team place CM1 firmly within this lineage, while its genome sequence marks it as a species new to science.

Before any virus can be used in food, it must survive the journey, and this is where CM1’s personality becomes clear. The team subjected the phage to a battery of environmental stress tests. Its infectivity faltered at pH values above 10 and also near pH 6, indicating a preference for neutral-to-alkaline conditions. Temperature profiling identified 30 degrees Celsius as the optimum, with viral titers declining both below and above this point. Salt told a similar story of gradual attrition: as sodium chloride concentrations rose from 1 percent to a punishing 35 percent, the phage titer decreased step by step. These parameters matter enormously in practice. Dairy processing involves refrigeration, heat treatments, brines and aggressive alkaline cleaning cycles, and a biocontrol agent must retain enough infectivity at the point of application to do its job. Encouragingly, as the food challenge test would later show, CM1 remained potent enough in real milk to deliver a significant blow to B. cereus — a sign that formulation and dosing can be tuned to fit its stability window.

The phage’s infection kinetics reveal an efficient predator. The researchers determined that the optimal multiplicity of infection — the ratio of virus particles to bacterial cells at the start of an experiment — is 1, meaning one phage per bacterium is enough to achieve maximum killing without wasting viral particles, an economically attractive trait for industrial use. Adsorption assays showed that 88.7 percent of phages had attached to host cells within just 35 minutes. Adsorption is the first, decisive step of the phage life cycle: reversible contact between tail fibers and the bacterial surface quickly matures into irreversible binding, followed by genome ejection into the cell. A fast, high-percentage adsorption rate means CM1 finds and disables its victims quickly, an important property in a food matrix where bacteria may be suspended in liquid, embedded in biofilms, or hiding in microscopic crevices. One-step growth experiments completed the kinetic portrait, allowing the team to map the rhythm of replication and release that underlies the phage’s killing power.

Perhaps CM1’s most marketable quality is its pickiness. When the researchers challenged the phage with a panel of different bacterial species alongside B. cereus isolates derived from food samples, the virus proved specific to B. cereus and demonstrated lytic activity against 69 percent of those isolates. Efficiency-of-plating analyses quantified how vigorously the phage grew on each susceptible strain. In medicine and food production alike, such specificity is a double-edged sword, but here the edges cut favorably. A virus that attacks only B. cereus will not disturb beneficial microbes, starter cultures or the wider food microbiota, a precision no broad-spectrum antibiotic or chemical disinfectant can match. At the same time, the fact that roughly a third of isolates resisted infection is a sobering reminder that no single phage is a silver bullet; commercial biocontrol typically relies on phage cocktails whose combined host ranges overlap to close the gaps.

The phage’s genome tells a reassuring story. Whole-genome sequencing revealed a double-stranded DNA molecule of 156,598 base pairs with a GC content of 39.7 percent. Bioinformatic screening of the sequence found no antimicrobial resistance genes and no virulence factors — a critical safety criterion, because a phage used in food must never act as a vehicle that ferries dangerous genes between bacteria. Nor does CM1 carry the toolkit of a temperate virus: it is strictly lytic, killing its host outright rather than integrating quietly into the bacterial genome, which is exactly the behavior desired in a biocontrol agent. Among the annotated genes, the tail-associated proteins carried domains related to depolymerases and lysins, two classes of enzymes with starring roles in phage attack. Depolymerases degrade the polysaccharide coatings and extracellular matrices that bacteria build around themselves, clearing a path for the virus to reach its receptor; lysins cleave peptidoglycan, the rigid mesh of the bacterial cell wall, from within during the final explosive step of replication.

Those very enzymes likely explain one of the study’s most practically important results: CM1 significantly reduced the biofilm biomass produced by B. cereus. Biofilms are the fortified cities of the microbial world — cells encased in a self-made matrix of polysaccharides, proteins and DNA that clings to surfaces and resists disinfectants at concentrations far above those that kill free-swimming bacteria. In dairy plants, B. cereus biofilms on pipes, valves and gaskets act as chronic contamination reservoirs, and because the bacterium also forms heat-resistant spores, even rigorous sanitation regimens rarely eliminate it completely. A phage armed with matrix-degrading depolymerases can do what chemical sanitizers struggle to accomplish: penetrate the biofilm’s protective sludge, reach the embedded cells, and dismantle the colony from the inside. For an industry haunted by product recalls and shelf-life losses attributable to B. cereus and its relatives, that capability alone makes CM1 worth serious attention.

The decisive experiment, however, took place in the product itself. In the food challenge test, milk was inoculated with B. cereus, and treatment groups received the mixture of bacterium and phage. The outcome was statistically unambiguous: the titer of B. cereus — the number of viable bacteria — was significantly decreased in the groups that received the phage, with a probability value below 0.05. In plain terms, adding CM1 measurably suppressed the pathogen in a real food matrix, not just in laboratory broth. This matters because milk is a demanding environment for phages: it is nutrient-rich but carries its own pH, fat and protein chemistry, and the study’s stability data showed that conditions near pH 6 can affect CM1’s infectivity. The fact that the phage still delivered a significant kill in milk suggests that, with proper dosing and timing, CM1 can overcome these barriers — a prerequisite for any future application in liquid milk processing or in the production of powdered milk, one of the commodities most vulnerable to B. cereus contamination.

CM1 arrives at a moment when phage biocontrol is moving from laboratory curiosity toward commercial reality, with phage products already approved in some jurisdictions for decontaminating food. Its credentials are strong: activity against the majority of B. cereus isolates tested, rapid adsorption, an economical optimal multiplicity of infection, demonstrable anti-biofilm power, a genome stripped of resistance and virulence genes, and proven efficacy in milk itself. The authors conclude that, given this combination of favorable properties, Bacillus phage CM1 is a promising and safe candidate biocontrol agent against B. cereus in food-related settings. The road from bench to dairy plant still requires larger trials, stable formulations that respect the phage’s temperature and salt sensitivities, combinations with complementary phages to widen coverage, and regulatory approval. But the underlying logic is compelling. Against a pathogen that hides in spores, fortifies itself in biofilms and shrugs off gentamicin in nearly every isolate tested, science has found an adversary with a 48-nanometer head, a 142-nanometer tail, and 156,598 base pairs of pure predatory intent. The milk industry, it seems, has just acquired a microscopic new ally.

Fresh-cut fruit is unusually difficult to preserve because cutting breaks the protective skin and exposes cells to oxygen, enzymes and microorganisms. In apples, tissue disruption allows polyphenol oxidase and peroxidase to contact phenolic compounds. These enzymes convert phenolics into quinones, which then react and polymerize into the brown pigments familiar on cut apple surfaces. At the same time, water loss accelerates, cell walls weaken and fungi can colonize the damaged tissue. Species including Penicillium expansum, Penicillium chrysogenum, Botrytis cinerea, Fusarium oxysporum, Aspergillus flavus and Aspergillus niger are associated with postharvest spoilage. Some fungi can also produce mycotoxins, making deterioration more than a cosmetic problem. The authors note that global apple losses can reach roughly one-quarter of production, underscoring the need for preservation methods that control several forms of deterioration at once.

The team first tested extracts made with solvents of different polarity to determine which one recovered the most active compounds from dried A. bisporus. Ethanol performed best, producing the broadest antifungal effects and an inhibition zone of 14 millimeters against P. chrysogenum in a disc-diffusion assay. The researchers then dried mushrooms at 45 degrees Celsius, ground them into a fine powder and exposed separate batches to gamma-radiation doses of 0, 2, 4, 6 or 8 kilograys. Gamma radiation is high-energy electromagnetic radiation capable of breaking chemical bonds and altering biological materials. In a food matrix, moderate exposure can disrupt cellular structures and release compounds that were previously bound within the tissue. It can also chemically transform existing molecules. But the same chemistry can become destructive at excessive doses, oxidizing or fragmenting sensitive compounds. The study therefore treated radiation dose as a variable to optimize, not simply as a higher-is-better intervention.

The strongest overall response occurred at 6 kilograys. At that dose, the extract contained 3.25 milligrams of gallic acid equivalents per gram, compared with 2.12 milligrams per gram in the non-irradiated control. The Folin–Ciocalteu measurement used by the researchers is an estimate of total phenolic content, expressed relative to gallic acid as a standard. Phenolic molecules are important because their hydroxyl groups can donate electrons or hydrogen atoms to reactive radicals, helping terminate oxidative chain reactions. Consistent with the chemical measurement, the irradiated extract neutralized 46.3 percent of the DPPH radical at a concentration of 100 micrograms per milliliter, compared with 40.9 percent for the untreated extract. The synthetic antioxidant TBHQ produced 96.8 percent inhibition under the same test conditions, showing that the mushroom preparation was not equivalent to a highly active purified antioxidant but nevertheless gained measurable activity through irradiation. At 8 kilograys, both phenolic content and antioxidant performance declined, supporting the idea that overexposure degraded sensitive compounds.

The antifungal experiments produced the same dose-dependent pattern. Extracts from irradiated mushrooms inhibited all six tested apple-spoiling fungi, with activity increasing through 6 kilograys and then falling at 8 kilograys. Against P. expansum, the inhibition zone expanded from 11.3 millimeters in the control extract to 16.3 millimeters after 6-kilograys treatment, an increase of about 44 percent. P. chrysogenum showed the largest response, with its inhibition zone reaching 20.3 millimeters, compared with 13.7 millimeters for the non-irradiated extract. The 6-kilograys preparation also produced zones of 17.3 millimeters against F. oxysporum, 16.3 millimeters against B. cinerea, 14.7 millimeters against A. flavus and 18.3 millimeters against A. niger. In each case, the response weakened at 8 kilograys. Statistical analysis indicated that radiation dose significantly affected inhibition-zone diameters, although the tests were conducted in triplicate and remain laboratory assays rather than evidence of commercial-scale performance.

Additional experiments provided clues about how the extract damages fungi. In a sorbitol-protection assay, the minimum inhibitory concentration of the irradiated extract increased when the growth medium contained 0.8 molar sorbitol. Sorbitol acts as an osmotic stabilizer: it can partially compensate for damage to a fungal cell wall, allowing a weakened cell to survive exposure that would otherwise stop growth. A shift in the minimum inhibitory concentration therefore suggests that the extract interferes with wall integrity. The researchers also found that the 6-kilograys extract reduced the activity of fungal extracellular enzymes, cutting protease activity by about 40 percent, cellulase by 35 percent and lipase by 45 percent. These enzymes help pathogens digest host tissues. Electron microscopy reinforced the biochemical results. Untreated hyphae appeared smooth, turgid and regularly branched, whereas treated fungi displayed collapsed hyphae, shrunken surfaces and deformed spores, with particularly pronounced effects in B. cinerea and P. expansum. Together, the results suggest a multifactorial mechanism involving cell-envelope damage and suppression of tissue-degrading metabolism.

Chemical profiling offered a possible explanation for the enhanced bioactivity. Using gas chromatography–mass spectrometry, the researchers detected changes in fatty acids and sterols after irradiation. The extract contained linoleic acid and related compounds, along with ergosterol and neoergosterol derivatives. At 6 kilograys, the relative abundance of sterols and medium-chain fatty acids increased compared with the non-irradiated material. Ergosterol rose from 1.03 percent to 3.09 percent, while some compounds, including neoergosterol and estra-1,3,5(10)-trien-17β-ol, appeared only after irradiation. These measurements describe relative abundance in the analyzed extract, not necessarily an increase in the total amount of each compound. Still, the altered chemical profile is consistent with radiation-induced breakdown, rearrangement and release of mushroom metabolites. Sterols and phenolics can affect fungal membranes and cell walls, while changes in the availability of bound compounds may help explain why moderate radiation strengthened activity. At higher doses, however, oxidation and polymerization may destroy the same molecules that contribute to antimicrobial effects.

The researchers next tested whether the optimized preparation worked on real fruit rather than only in culture plates. They cut apples into two-centimeter-thick slices and dipped them for three minutes in either water, a 10 percent weight-to-volume solution of non-irradiated mushroom extract or the same concentration of extract made from mushrooms treated at 6 kilograys. The slices were stored at approximately 4 degrees Celsius for 10 days. By the end of storage, untreated apples had lost 6.2 percent of their initial mass, while slices treated with non-irradiated and irradiated extracts lost 4.2 and 3.0 percent, respectively. Firmness also declined in all groups, but the irradiated-extract treatment slowed the loss: control slices fell from 15.5 newtons initially to 10.0 newtons after 10 days, whereas treated slices retained 12.5 newtons. The extract may have formed a thin protective layer that limited water transfer, while its antioxidant and enzyme-inhibitory effects may have helped stabilize cell-wall structures.

The most visible benefit was reduced discoloration. Apple slices coated with the irradiated extract maintained lower color change and browning-index values than both untreated slices and those given the non-irradiated preparation. By limiting oxidative reactions, phenolic compounds could reduce the accumulation of quinones that generate brown pigments; antioxidant molecules may also interfere with the reactive oxygen chemistry that sustains browning. After 10 days, the treated apples had about 1.3-log fewer fungi and yeasts and 1.6-log fewer bacteria than the control, reductions that correspond to roughly 20-fold and 40-fold decreases, respectively, on a base-10 scale. The authors report no visible off-odors or obvious tissue damage, but the study did not include a formal sensory panel or flavor analysis. Nor did the storage experiment deliberately inoculate apples with individual pathogens. The microbial results therefore reflect natural contamination conditions, while the pathogen-specific evidence comes primarily from laboratory assays.

The findings do not yet establish that irradiated mushroom extract is ready to replace commercial apple preservatives. The study used a limited number of independent batches and a relatively short storage period, and larger trials will be needed to determine consistency across apple varieties, harvest conditions and industrial handling systems. Researchers must also assess taste, aroma, consumer acceptance, extract stability, production cost and regulatory requirements. Controlled challenge tests could reveal how effectively the coating works against P. expansum and B. cinerea directly on fruit, while further experiments are needed to determine whether it affects mycotoxin production. The authors describe such investigations as ongoing. Even with these caveats, the work demonstrates an intriguing form of chemical tuning: moderate gamma irradiation did not simply sterilize the mushroom material, but altered its extractable chemistry and biological performance. If those effects can be reproduced safely and economically, an ordinary edible mushroom could become the source of a multifunctional coating designed to keep cut fruit fresher for longer.