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 motivation behind the work stems from a growing unease within the food industry about the additives long used to keep processed meats from going rancid. Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) work by stabilizing free radicals and thereby slowing lipid oxidation, the chemical cascade that turns fats stale and unpalatable. Yet BHA has been classified by the U.S. National Toxicology Program as reasonably anticipated to be a human carcinogen, and recent network toxicology analyses have suggested potential liver, kidney, and nerve toxicity associated with both compounds. As consumers increasingly demand clean-label products, food scientists have turned to plant materials rich in bioactive compounds, including buckwheat, green tea, and licorice, in search of safer preservative strategies.

Magnolia denudata emerged as a promising candidate because its flowers are packed with polyphenols and flavonoids, two families of plant secondary metabolites renowned for their ability to quench reactive radicals. The blossoms also contain distinctive phenolic compounds such as rutin, chlorogenic acid, magnolol, and honokiol, which previous research has linked to antibacterial, anti-inflammatory, and antioxidant activity. To prepare the extract, the team harvested fully bloomed flowers in April 2024 from trees on the Chungbuk National University campus, dried them at room temperature, and soaked them in an 80 percent ethanol solution for one week in a shaking water bath at 37 degrees Celsius. After filtration, vacuum concentration, and freeze-drying, the process yielded a dry extract at 5.33 percent of the original flower weight, with a coefficient of variation below 2 percent across three independent batches.

Laboratory characterization confirmed the extract’s potency. In the DPPH radical scavenging assay, a standard test in which a stable purple radical turns yellow upon neutralization by antioxidants, the extract achieved a scavenging rate of 44.48 percent. That figure compares favorably with other edible spring flowers, exceeding forsythia at 40.4 percent and rhododendron at 34.5 percent, and narrowly outperforming cherry blossom at 43.3 percent. The extract contained 132.91 milligrams of gallic acid equivalents per gram in total polyphenols and 42.44 milligrams of naringin equivalents per gram in total flavonoids, values consistent with earlier analyses of the species and pointing to a dense concentration of the molecular machinery responsible for radical interception.

With the extract characterized, the researchers formulated emulsified chicken breast sausages containing ground chicken, pork backfat, ice, salt, and sugar, adding the freeze-dried extract powder at 0.1, 0.15, and 0.2 percent by weight. A negative control received no additives, while a positive control contained 0.1 percent ascorbic acid, a well-established antioxidant benchmark. The emulsions were stuffed into tubes, cooked in an 80 degree Celsius water bath for 30 minutes, and stored under refrigeration at 4 degrees Celsius for two weeks while the team tracked an array of quality indicators, from proximate composition and color to pH, lipid oxidation, and protein breakdown.

The proximate analysis revealed a clear concentration-dependent pattern. Sausages containing the extract held significantly more moisture than either control, with moisture rising as the dose increased from 0.1 to 0.2 percent. The researchers attribute this to insoluble dietary fibers such as cellulose and lignin in the flower material, which bind water within the emulsion matrix. Correspondingly, protein content declined relative to the untreated control, an effect the authors liken to earlier observations with mustard powder, where fiber-driven moisture gain dilutes the relative protein fraction. Fat and ash contents shifted only modestly, with the highest-dose group showing the lowest fat percentage, likely a dilution effect of its greater water content.

Two processing metrics told perhaps the most commercially compelling story. Cooking yield, the proportion of weight retained after heat treatment, ranged from 82.81 to 86.26 percent and was significantly higher in every extract-treated group than in either control, climbing steadily with concentration. Water-holding capacity followed a similar trajectory, with the 0.15 and 0.2 percent groups significantly outperforming the untreated control. The mechanism, the researchers suggest, is twofold: the insoluble fibers physically trap water, while the abundant polyphenols inhibit protein oxidation, preserving the structural integrity of the meat matrix and its ability to bind moisture. For manufacturers, higher yields and better water retention translate directly into reduced cooking losses and juicier products.

During refrigerated storage, the extract’s preservative effects became even more pronounced. Thiobarbituric acid reactive substances, or TBARS, the standard proxy for fat oxidation measured as malonaldehyde equivalents, were significantly lower in all extract-treated sausages than in the untreated control at every time point, with the 0.2 percent group showing the slowest rise over the two weeks. Volatile basic nitrogen, a marker of protein degradation driven by microbial activity, was also significantly reduced in the highest-dose group throughout storage. The authors point to the flower’s essential oil chemistry as a plausible explanation: previous analyses identified 3-carene, comprising 77.07 percent of magnolia flower oil, as active against spoilage bacteria such as Brochothrix thermosphacta and Pseudomonas fluorescens, while beta-elemene shows effectiveness against foodborne pathogens including Staphylococcus aureus. Slower microbial growth means fewer alkaline amines and ammonia compounds, which in turn kept pH values more stable in the treated sausages than in the controls.

Color measurements added nuance to the picture. Redness increased with extract concentration, consistent with the pigmented nature of polyphenols and flavonoids, while lightness was lowest in the mid-dose group. Yellowness rose in the lower-dose treatments, likely reflecting the extract’s inherent brownish hue, though the 0.2 percent group showed no significant difference from the untreated control, an optical effect the authors attribute to pigment dilution by the higher moisture content. A trained sensory panel of ten evaluators, however, flagged a trade-off at the highest dose: bitterness scores climbed with concentration, consistent with the known astringency of concentrated polyphenols, and overall preference was lowest for the 0.2 percent sausages. The ascorbic acid control retained the highest overall acceptability, while the 0.1 and 0.15 percent treatments scored in between.

The findings position Magnolia denudata extract as a functional, natural antioxidant capable of enhancing cooking yield, water retention, and oxidative and microbial stability in emulsified chicken products, with 0.2 percent emerging as the most effective functional dose. The remaining challenge is sensory: preserving the extract’s preservative benefits while tempering the bitterness that concentrated polyphenols impart. The authors suggest that future formulation strategies, perhaps blending the extract with masking ingredients or adjusting processing techniques, could reconcile function with flavor. As meat consumption in South Korea continues its climb toward a projected 60 kilograms per person by 2027, and as regulators and consumers alike push industry away from synthetic additives, a springtime flower long prized for its perfume may find a second career quietly protecting the sausages in the refrigerated aisle.

Subject of Research: Use of Magnolia denudata flower extract as a natural antioxidant to improve quality and storage stability of emulsified chicken sausages

Article Title: Effects of Magnolia denudata extract on quality and storage characteristics of emulsified chicken sausage

Article References: Ku, B., Kim, M., Kang, J., Han, H., Park, G., Lee, S.-H., & Choi, J. (2026). Effects of Magnolia denudata extract on quality and storage characteristics of emulsified chicken sausage. Food Science of Animal Resources, 46(1), Article 70. https://doi.org/10.1007/s44463-025-00026-9

Image Credits: AI Generated

DOI: 10.1007/s44463-025-00026-9

Keywords: Magnolia denudata, natural antioxidants, chicken sausage, lipid oxidation, TBARS, volatile basic nitrogen, polyphenols, flavonoids, water-holding capacity, cooking yield, food preservation, meat science

The research team, led by Snigdha Homroy and Rajni Chopra at the National Institute of Food Technology Entrepreneurship and Management in Kundli, Haryana, collected discarded Tagetes erecta flowers from a local temple within six to eight hours of generation and processed them within a day to minimise the loss of volatile phytochemicals. The flowers, which had a moisture content of approximately 88 percent, were gently crushed rather than milled to preserve the delicate glandular trichomes that house the oil-bearing volatiles. From this waste stream, the researchers extracted marigold essential oil using four different approaches: conventional hydro-distillation, ultrasound-assisted hydro-distillation, freeze-thaw-assisted hydro-distillation and solvent-free microwave extraction.

The choice of extraction route proved decisive. Hydro-distillation in a Clevenger-type apparatus for four hours yielded 0.0164 grams of oil per 100 grams of fresh flowers. When the flowers were first pre-treated with ultrasound at 500 watts and 20 kilohertz, acoustic cavitation, the violent formation and collapse of microscopic bubbles, tore open cell structures and improved solvent penetration, raising the yield by roughly 25 percent. A freeze-thaw pre-treatment, in which flowers were cycled between minus 80 degrees Celsius and room temperature three times, boosted the yield by about 17 percent, because ice crystals physically rupture cell walls and membranes during freezing, enlarging the porous network available to the extracting water.

Solvent-free microwave extraction, by contrast, performed poorly in this matrix, delivering a yield 85.3 percent lower than conventional hydro-distillation. The authors attribute this to the absence of added water and the limited intrinsic free moisture of the flowers, which restricted internal heating and volatilisation of the essential oil. The result is a useful reminder that green extraction technologies are not universally interchangeable: microwave methods that excel with aromatic herbs, as previous work on rosemary showed, can falter with high-moisture, fibrous floral waste. The relatively low absolute yields across all methods also reflect the use of whole flowers, which mix oil-rich tissues with fibrous, low-oil material, and the reporting of yields on a fresh-weight basis.

Chemical profiling by headspace gas chromatography-mass spectrometry identified 41 phytochemical constituents across the oils, with a profile rich in compounds prized for antioxidant, antimicrobial and anti-inflammatory activity. Nootkatone, limonene, tagetone, piperitone, ocimene, beta-caryophyllene and isoeugenol dominated, although their proportions shifted with the extraction method. Ultrasound-assisted hydro-distillation produced the highest overall content of key volatiles, enriching oxygenated sesquiterpenes and ketones such as nootkatone, which reached 11.15 percent, while freeze-thaw treatment similarly favoured sesquiterpenes. Microwave extraction skewed toward lighter hydrocarbons and phenolics, including isopentane and isoeugenol, which contribute aroma but are less relevant to oxidative protection.

The second half of the study tested whether this waste-derived oil could defend perilla seed oil, a cold-pressed, omega-3-rich oil whose high polyunsaturated fatty acid content makes it exceptionally vulnerable to rancidity. The researchers fortified the oil with marigold essential oil at 500, 1000 and 1500 parts per million and compared the results against 200 parts per million of tert-butylhydroquinone, or TBHQ, the synthetic antioxidant benchmark, and an untreated control. Samples were then subjected to a 20-day Schaal oven test at 60 degrees Celsius, an accelerated storage protocol that compresses months of ambient shelf-life degradation into weeks by speeding the same radical chain reactions that occur in normal storage.

Across every measure, the 1500 ppm marigold treatment performed impressively. Rancimat analysis showed a statistically significant, concentration-dependent extension of the induction period, indicating delayed oxidation onset. Viscosity, which climbs as oxidation generates polymeric degradation products, rose only to 37.1 centipoise in the marigold-fortified oil, compared with 40.3 centipoise in the untreated control. The untreated oil’s peroxide value, a gauge of primary oxidation, soared to 28.63 milliequivalents of oxygen per kilogram by day 20, whereas the marigold-supplemented oil held at 10.03 and TBHQ at 9.71. Acid value, p-anisidine value and conjugated triene content, which track hydrolysis and secondary aldehyde and ketone formation, followed the same pattern, with the highest marigold dose approaching TBHQ performance throughout.

Antioxidant capacity assays reinforced the picture. Untreated perilla oil lost radical-scavenging capacity rapidly, with DPPH inhibition falling from 84.42 to 74.35 percent and ABTS inhibition from 80.15 to 66.40 percent over the storage period. The 1500 ppm marigold sample, by contrast, retained 83.86 percent DPPH and 72.94 percent ABTS inhibition after 20 days, losses of less than seven percent, comparable to TBHQ-treated oil. The oil also preserved its golden carotenoid pigments better, retaining a yellow Lovibond value of 12.2 against 9.1 for the control. Hierarchical cluster analysis of all stability parameters grouped the control and 500 ppm samples together as low-stability outliers while placing the 1500 ppm marigold oil in the same high-stability cluster as TBHQ, a statistical confirmation that the floral waste extract can match a regulated synthetic preservative at its maximum permitted concentration.

The protective mechanism stems from the oil’s constellation of bioactive volatiles, which scavenge free radicals, chelate pro-oxidant metals and interrupt lipid peroxidation chain reactions, with synergy among compounds such as beta-caryophyllene, nootkatone and isoeugenol likely amplifying the effect. The study’s significance extends beyond food chemistry. It couples two sustainability goals at once: diverting a vast, culturally generated waste stream from landfill and offering food manufacturers a clean-label alternative to synthetic antioxidants such as BHA, BHT and TBHQ, whose potential carcinogenic, genotoxic and endocrine-disrupting effects have drawn increasing scrutiny in animal and mechanistic studies. The authors note that future work should clarify the underlying preservation mechanisms and extend testing to other oxidation-sensitive oils such as flaxseed and chia. If those trials succeed, the garlands left behind at temples across India could become a genuine industrial resource, turning ritual offerings into shelf life for the world’s healthiest cooking oils.

Subject of Research: Extraction of essential oil from marigold floral waste and its use as a natural antioxidant to stabilise polyunsaturated fatty acid-rich perilla seed oil.

Article Title: Valorisation of marigold floral waste for essential oil extraction and its application in stabilisation of PUFA rich perilla seed oil

Article References: Homroy, S., Madan, H., Sharma, S., Chopra, R., & Kumari, R. (2026). Valorisation of marigold floral waste for essential oil extraction and its application in stabilisation of PUFA rich perilla seed oil. Discover Green Chemistry, 1(1), Article 16. https://doi.org/10.1007/s44509-026-00015-1

Image Credits: AI Generated

DOI: 10.1007/s44509-026-00015-1

Keywords: marigold floral waste, Tagetes erecta, essential oil, hydro-distillation, ultrasound-assisted extraction, solvent-free microwave extraction, perilla seed oil, natural antioxidants, oxidative stability, TBHQ, omega-3, waste valorisation

The industrial problem they target is both old and enormous. Oxidation is one of the principal mechanisms of food deterioration, degrading nutritional quality, altering flavor, aroma and color, and shortening shelf life, particularly in lipid-rich products. To fight it, manufacturers have long relied on synthetic antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and tert-butylhydroquinone (TBHQ). Yet mounting evidence of potential health risks, combined with a consumer shift toward natural ingredients and transparent ‘clean label’ products, has intensified the search for plant-based alternatives that can do the same job without the baggage of synthetic chemistry.

Phenolic compounds are the leading candidates in that search. This broad class of plant secondary metabolites includes flavonoids, phenolic acids and tannins, and their antioxidant power arises from a set of complementary chemical mechanisms: they scavenge free radicals, chelate transition metal ions that catalyze oxidation, and interrupt the chain reactions by which lipid peroxides propagate. When these mechanisms operate in a food matrix, lipid oxidation is delayed and shelf life is extended. The challenge is that plants produce these compounds as defensive responses to environmental stress, so their abundance depends heavily on where and how a species grows, and extracting them efficiently without damaging them has been an enduring technical obstacle.

This is where the Caatinga becomes strategically interesting. The biome’s plants endure high temperatures, intense solar radiation and prolonged water deficit, conditions that push them to biosynthesize phenolics as adaptive protection against oxidative stress. In other words, the very harshness that makes the Caatinga inhospitable appears to make its flora chemically rich. Barbatimão exemplifies the point. A member of the Fabaceae family, the species concentrates tannins, particularly in its bark, alongside flavonoids such as rutin and catechins and phenolic acids including gallic and caffeic acids. Its bark has a long history of empirical use in teas, tinctures and sitz baths for wounds, ulcers, gastritis and inflammatory conditions, and modern laboratory studies have shown that bark and leaf extracts exhibit pronounced free radical scavenging, lipid peroxidation inhibition and metal chelation activity.

Despite this promise, the authors argue that the technological valorization of Caatinga antioxidants has been held back by conventional methodology. Most published work relies on extraction systems built around volatile organic solvents that are poorly selective, energy-intensive and difficult to translate to food-grade applications, a mismatch with both green chemistry principles and current regulatory and consumer expectations. Conventional hydroalcoholic extraction, the standard approach in barbatimão research to date, may also leave complex phenolic fractions, such as high-molecular-weight condensed tannins, insufficiently extracted or chemically degraded during processing, meaning the full antioxidant arsenal of the plant has likely been underestimated.

The proposed solution is a pairing of two green technologies: natural deep eutectic solvents (NADES) and ultrasound-assisted extraction (UAE). NADES are tunable liquid systems formed by combining hydrogen bond acceptors, such as choline chloride, with hydrogen bond donors, including organic acids like lactic and citric acid, polyols such as glycerol, amino acids and sugars. Their effectiveness rests on extensive hydrogen-bonding networks and polarity matching, which favor the solubilization of hydroxylated aromatic structures, precisely the architecture of flavonoids, phenolic acids and condensed tannins. Choline chloride–organic acid and choline chloride–polyol combinations have already demonstrated high efficiency in pulling quercetin derivatives, gallic acid and catechins out of plant matrices.

Selectivity is the standout advantage. Because solvent composition can be rationally designed, acidic NADES systems tend to favor phenolic acids, while polyol-based systems are more effective for flavonoids and bulky tannins. This design flexibility means researchers can target specific bioactive fractions rather than accepting whatever a generic solvent happens to dissolve. The main technical limitation of NADES, their relatively high viscosity, which slows mass transfer, can be mitigated by adding water or by coupling the solvent with ultrasound. Acoustic cavitation disrupts cell walls, enhances solvent penetration into the plant tissue and accelerates mass transfer. Under optimized NADES–UAE conditions, recent studies across diverse plant materials report significant increases in total phenolic content and antioxidant activity, often exceeding conventional organic solvents while cutting extraction time and solvent consumption.

Applying this technology to barbatimão would be unprecedented, and the authors argue it could unlock underexplored phenolic fractions and clarify antioxidant mechanisms such as metal chelation and lipid oxidation inhibition that current extracts capture only partially. The food applications are equally forward-looking: many NADES constituents are non-volatile, low in toxicity and, in some cases, edible, which raises the possibility of using extracts directly or with minimal downstream processing, reducing costs and environmental impact while supporting clean-label claims. Computational tools are accelerating the design stage too, with approaches such as COSMO-RS, a Conductor-like Screening Model for Real Solvents, and machine learning enabling researchers to predict solvent–solute interactions and rationally tailor solvents to specific phenolic targets before any benchwork begins.

Significant hurdles remain before Caatinga antioxidants reach industrial shelves. Solvent viscosity, compound recovery, sensory impact on foods, and compliance with food safety regulations must all be systematically evaluated, and while NADES components are often regarded as safe, dedicated regulatory frameworks for their direct use in food systems are still under development, underscoring the need for toxicological and safety studies. The authors outline a research roadmap: rational optimization and scale-up of NADES systems with sustainability metrics such as energy efficiency, solvent recyclability and life cycle assessment; advanced chemical profiling using HPLC-DAD-MS/MS and metabolomics to identify bioactive fractions; and validation in real food matrices with kinetic and mechanistic analyses of antioxidant performance during processing and storage. Within that roadmap, S. rotundifolium serves as a proof-of-concept species, a demonstration of how one of Earth’s harshest and least-studied biomes can supply the sustainable, science-grounded ingredients that the food industry increasingly demands.

Subject of Research: Phenolic-based natural antioxidants from Caatinga plants as sustainable food additives using green extraction technologies

Article Title: Natural antioxidants from the Caatinga with insights from Stryphnodendron rotundifolium as a model for phenolic-based food additives

Article References: Ribeiro, M. A. M., Ferreira dos Santos, I. R., de Lima Pereira, J. F., Xenofonte, J. V. F., & da Costa, J. G. M. (2026). Natural antioxidants from the Caatinga with insights from Stryphnodendron rotundifolium as a model for phenolic-based food additives. Discover Green Chemistry, 1(1), Article 17. https://doi.org/10.1007/s44509-026-00019-x

Image Credits: AI Generated

DOI: 10.1007/s44509-026-00019-x

Keywords: phenolic compounds, Caatinga biome, Stryphnodendron rotundifolium, natural antioxidants, NADES, ultrasound-assisted extraction, green chemistry, food additives, tannins, clean label, Natural, antioxidants

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