The study, published in Food Chemistry: X, explores what happens when low-density polyethylene (LDPE), the soft, flexible plastic commonly used for produce bags, is blended with raw diatomite, alkaline-activated diatomite, potassium permanganate, and potassium permanganate impregnated into activated diatomite. Diatomite, also known as diatomaceous earth, is an amorphous silica material formed from the fossilized cell walls of microscopic aquatic algae. It is remarkably porous, with voids making up roughly 80 to 90 percent of its volume, chemically inert, and inexpensive, which makes it attractive as a low-cost adsorbent. Its surface carries silicon hydroxyl groups that can attract organic molecules such as ethylene, but in its natural state the density of these groups is often too low to be highly effective.

To unlock diatomite’s full adsorption potential, the researchers activated it with a strong alkaline treatment. Purified diatomite powder was milled through a 200-mesh sieve, washed, and then immersed in 5 molar sodium hydroxide solution at 85 degrees Celsius for one hour. This harsh chemical bath dissolves impurities that clog the mineral’s natural pores and induces partial dissolution and rearrangement of its structural ions, increasing the specific surface area and optimizing the distribution of surface functional groups. The activated material was then impregnated with potassium permanganate by soaking it in a 2 normal KMnO4 solution at low temperature, yielding particles with a manganese oxide content of roughly 18.5 percent and a permanganate uptake of about 2.82 grams per 100 grams of diatomite, a loading comparable to commercial ethylene-scavenging sachets.

The treated and untreated particles were then compounded into LDPE using industrial melt processing. The team first prepared 10 percent masterbatches in a twin-screw extruder and then diluted them into blown films containing 1, 3, and 5 weight percent of each filler, producing films 30 to 40 micrometers thick. This manufacturing route matters because it uses the same equipment that produces commercial packaging, meaning the concept could, in principle, be scaled without exotic new machinery. Spectroscopic analysis confirmed that the polymer matrix remained chemically intact and that the permanganate was retained in an active form within the films, while thermal analysis showed that diatomite slightly raised the onset of thermal degradation from 447 to about 459 degrees Celsius, thanks to the mineral’s insulating character.

The ethylene removal results revealed a striking and somewhat counterintuitive pattern. In powder form, the alkaline-activated, permanganate-impregnated diatomite was the star performer, removing about 909 microliters of ethylene per gram within 24 hours, far outpacing neat potassium permanganate powder, whose limited gas-accessible surface and tendency to agglomerate hampered its performance. Once embedded in LDPE films, however, the picture changed. The best-performing films were those containing just 1 weight percent of the impregnated particles, which removed 373 microliters of ethylene per gram over 48 hours, and 1 weight percent of plain diatomite, which removed 297 microliters per gram. Surprisingly, raising the loading to 3 or 5 percent actually reduced ethylene removal. Scanning electron microscopy explained why: at higher loadings, the polar mineral particles clump into large agglomerates within the non-polar polymer, burying active sites and blocking gas transport, while at 1 percent the particles disperse relatively uniformly.

The study also delivered a sobering lesson about gas barriers. Contrary to what has been reported for some other mineral-polymer systems, adding diatomite did not improve the films’ resistance to gas diffusion. The oxygen transmission rate of the 1 percent diatomite film actually increased by about 132 percent compared with neat LDPE, and water vapor transmission rose slightly as well. The researchers attribute this to a fundamental mismatch: hydrophilic diatomite, covered in silanol groups, bonds poorly with hydrophobic polyethylene, creating microscopic voids at the interface through which gases pass more easily. Mechanical properties told a similar story, with tensile strength and elongation declining as filler content increased, although films with 1 percent alkaline-activated diatomite retained strength values between 15 and 19 megapascals, comparable to commercial LDPE films used for fresh produce. Optical clarity, meanwhile, was essentially preserved at 1 percent loading, an important consideration for shoppers who want to see the fruit they are buying.

The decisive test came with real bananas. Mature green bananas harvested in Ratchaburi Province, Thailand, were packed individually in bags made from neat LDPE, 1 percent diatomite LDPE, or 1 percent permanganate-impregnated activated diatomite LDPE, then stored for 10 days at 25 degrees Celsius alongside an unpacked control group. The results were dramatic. Unpacked bananas lost nearly 18 percent of their weight and developed dark spots and dried peel by day 6, while all packaged fruits stayed within 2 to 3 percent weight loss. But the packaging types diverged sharply in how well they slowed ripening itself. Bananas in the 1 percent diatomite film kept their green peel through the entire 10-day storage period, showed only a slight decline in firmness, and reached a total soluble solids level of just 6.97 degrees Brix by day 10, compared with 16.63 degrees Brix for bananas in plain LDPE and 9.80 degrees Brix for the unpacked control.

Perhaps the most intriguing finding is that the film with the highest measured ethylene removal was not the best at preserving the fruit. The permanganate-impregnated film removed more ethylene in closed-vial tests, yet the plain diatomite film delivered superior banana quality. The authors suggest that postharvest performance is governed not by ethylene scavenging alone but by the balance among ethylene removal, gas permeability, and moisture regulation. The higher oxygen transmission of the diatomite film may have helped maintain healthy aerobic respiration, while its higher water vapor permeability prevented condensation on the fruit surface, avoiding the peel softening and lenticel damage associated with saturated humidity. The researchers are careful to note that their closed-vial measurements do not directly represent the dynamic atmosphere inside a package containing respiring fruit, and that simultaneous monitoring of ethylene, oxygen, and carbon dioxide in actual packages will be needed to disentangle these effects.

The team is equally candid about the limits of the work. The films remain a laboratory-scale proof of concept: long-term stability of the polymer matrix, potential migration of permanganate or manganese into food, and overall food-contact safety were not evaluated, so the materials cannot yet be considered suitable for direct commercial use. Still, the study opens a genuinely novel direction. Diatomite had never before been investigated as an ethylene adsorbent embedded in a polymer matrix for fruit packaging, and the finding that a simple, cheap, unmodified mineral at just 1 percent loading can outperform more elaborate chemically treated formulations is the kind of result that could reshape how the packaging industry thinks about active films. If subsequent safety and scale-up studies succeed, the fossilized shells of ancient algae, one of nature’s most abundant porous materials, could soon be quietly working inside the plastic bags at the grocery store, buying bananas and other climacteric fruits an extra week of freshness and keeping a little more of the global harvest out of the bin.

Subject of Research: Ethylene-scavenging LDPE composite films with diatomite and potassium permanganate for extending banana shelf life

Article Title: Effect of diatomite and KMnO 4 -impregnated diatomite in LDPE films on ethylene removal and postharvest quality of bananas

Article References: Yann, T., Winotapun, C., Yos, P., Voon, L. H., Wong, Y. H., Ngamchuachit, P., & Boondamnoen, O. (2026). Effect of diatomite and KMnO4-impregnated diatomite in LDPE films on ethylene removal and postharvest quality of bananas. Food Chemistry: X, 39, Article 104499. https://doi.org/10.1016/j.fochx.2026.104499

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104499

Keywords: ethylene scavenger, diatomite, potassium permanganate, LDPE film, active packaging, banana shelf life, postharvest quality, food packaging, blown film extrusion, climacteric fruit, alkaline activation, Food Chemistry: X

The team’s strategy rests on the Maillard reaction, the same non-enzymatic chemistry that browns bread crust and sears steak. In food science, this reaction can be harnessed deliberately: a reducing sugar is covalently grafted onto the free amino groups of a protein, producing a protein-polysaccharide conjugate with improved solubility, antioxidant activity and interfacial behavior. The researchers chose galacto-oligosaccharides, or GOS, as their grafting partner, a prebiotic carbohydrate derived from lactose that is already valued for feeding beneficial gut bacteria. When carefully controlled, wet-heating glycosylation at 90 degrees Celsius for just 15 minutes can attach GOS to protein while avoiding the pitfalls of overdone Maillard chemistry, such as excessive browning, protein crosslinking and the formation of advanced glycation end-products.

The central insight of the study is that the history of the protein before conjugation matters as much as the conjugation step itself. The team compared two extraction routes. The conventional route used alkaline solubilization at pH 9 with stirring, precipitation at the isoelectric point and freeze-drying, yielding around 39.7 milligrams of protein per gram of flour at best. The microwave-assisted route, optimized through a nine-run screening design in a Labotron 12T system, hit its peak at 400 watts for 20 minutes at pH 9, delivering 293.72 milligrams per gram, roughly seven times the conventional yield. The rapid volumetric heating disrupts the cellular matrix and releases protein efficiently, but crucially it also appears to leave the protein in a partially unfolded state with more reactive amino groups exposed.

That conformational legacy showed up clearly in the structural data. Fourier-transform infrared spectroscopy revealed that the microwave-extracted conjugate, dubbed LPIGHM, showed the strongest evidence of carbohydrate incorporation, with a pronounced growth of the carbon-oxygen stretching envelope between 1200 and 1000 per centimeter and a weakening of the ordered amide bands. Differential scanning calorimetry and thermogravimetric analysis painted the same picture: the microwave-derived conjugate displayed the most complex thermal profile and enhanced structural integrity compared with the non-heated mixture and the conventionally prepared conjugate. Secondary-structure analysis showed beta-sheet content falling from 56.7 percent in native lupin protein to 50.0 percent in LPIGHM, with beta-turns and random coil rising in compensation, a shift from rigid order toward flexible disorder that favors interfacial performance.

Perhaps the most dramatic structural change was in particle size. Native lupin protein isolate was heavily aggregated, with a mean hydrodynamic diameter of 1775 nanometers, a figure the authors caution is skewed by a minority population of large clumps. After glycation, the conjugates shrank dramatically: 152 nanometers for the simple mixture, 99 for the conventionally prepared conjugate and 89.7 nanometers for the microwave-derived one, an apparent 19.8-fold reduction. Surface hydrophobicity collapsed in parallel, from 443 arbitrary units for the native protein to just 62.5 for LPIGHM, as hydroxyl-rich GOS chains replaced exposed apolar side chains on the particle surface. Fluorescence spectroscopy confirmed tertiary structural rearrangement, with tryptophan emission quenching and blue-shifting most strongly in the microwave-derived conjugate.

These structural shifts translated directly into functional gains. Foaming capacity of the native protein was a dismal 10 percent with 4 percent stability; the microwave-derived conjugate reached 64 percent capacity and 36 percent stability, increases of 6.4-fold and 9-fold respectively. Emulsifying activity index climbed from 7.2 to 74.2 square meters per gram, a tenfold improvement, while emulsion stability rose from 40.2 to 71.6 minutes. Water-holding capacity more than doubled to 2.9 grams per gram, and oil-holding capacity rose to 14.6 grams per gram. Solubility at neutral pH improved only modestly, from 31.5 to 33 percent, which the authors attribute to measuring well away from the isoelectric region where glycation exerts its largest effect on plant proteins.

Correlation analysis across the four treatment means reinforced the mechanistic story. The apparent degree of grafting, measured by the loss of free amino groups, was the strongest single predictor of performance, correlating at r = 0.99 with foaming capacity and r = 0.98 with emulsifying activity. Surface hydrophobicity correlated negatively with solubility and interfacial function, and particle size and beta-sheet content tracked negatively with emulsion stability. Notably, zeta potential showed no strong association with any interfacial property, supporting the authors’ argument that stabilization in these conjugates is steric and hydration-driven rather than electrostatic: the attached carbohydrate layer displaces the shear plane outward and screens the underlying charges, so a less negative zeta potential can coexist with more bound sugar and better stability.

The biological results were more nuanced and enzyme-specific. Alpha-glucosidase inhibition improved roughly fourfold in all GOS-containing systems, reaching 60 to 66 percent at 100 milligrams per milliliter, an effect present even in the non-heated mixture, suggesting the oligosaccharide itself contributes to binding at the enzyme’s pocket-shaped active site. Alpha-amylase inhibition, by contrast, was not improved and declined at low concentrations, plausibly because the hydrated sugar chains obstruct the enzyme’s extended substrate-binding cleft. ACE inhibition remained modest throughout. Antioxidant activity rose in an assay-dependent fashion: the microwave-derived conjugate excelled at ABTS radical scavenging, reaching 43.9 percent at the lowest tested concentration versus 12.8 percent for native protein, while the conventionally prepared conjugate showed the strongest reducing power and total antioxidant capacity. Against Caco-2 colorectal cancer cells, antiproliferative activity was substantial, though the native protein was the most active at 86.2 percent, and the microwave-derived conjugate partially preserved activity after heating.

The gut microbiota experiments provided the study’s most forward-looking results. Using pooled fecal slurries from six healthy adult donors in an in vitro fermentation model, the team found that the conjugates, particularly the microwave-derived one, produced the most gas, retained more acetate at 24 hours than the free GOS mixture, and fostered the most even microbial community, with a Shannon index of 3.23 versus 1.85 for the untreated control. Beneficial genera such as Bifidobacterium and Lactobacillus were enriched while opportunistic taxa including Escherichia and Klebsiella declined. PICRUSt2 functional prediction pointed to enhanced carbohydrate and energy metabolism pathways. The authors are careful to note that short-chain fatty acid concentrations declined over the incubation rather than accumulating, that the fermentation was run without simulated digestion, and that the predicted pathways reflect metabolic potential rather than measured activity.

The study’s limitations are candidly acknowledged. The design did not include a microwave-extracted protein carried through without conjugation, so the effects attributed to LPIGHM belong to the combined process rather than to microwave extraction alone. The degree of grafting is an apparent value that cannot distinguish sugar attachment from conformational masking of amino groups, and the correlation analysis rests on only four treatment means. Confirming the full picture will require mass-spectrometric mapping of glycation sites, quantification of advanced glycation end-products and available lysine, digestion studies before fermentation, and trials in real food matrices. Even so, the core message stands: how a plant protein is extracted shapes how well it can be engineered afterward. For food formulators wrestling with the functional shortcomings of legume proteins, the microwave is looking less like a shortcut and more like a strategic first move.

Subject of Research: Microwave-assisted extraction of lupin protein isolate to enhance Maillard glycation with galacto-oligosaccharides for improved functionality and gut fermentability

Article Title: Microwave-assisted extraction enhances wet-heating Maillard glycation of lupin protein with galacto-oligosaccharides: structural basis for improved interfacial functionality and gut fermentability

Article References: Ullah, N., Bamigbade, G., Arachchi, M. J. P., Ali, A., Kamal-Eldin, A., Zhou, F., Miao, S., & Ayyash, M. (2026). Microwave-assisted extraction enhances wet-heating Maillard glycation of lupin protein with galacto-oligosaccharides: structural basis for improved interfacial functionality and gut fermentability. Food Chemistry: X, 39, Article 104518. https://doi.org/10.1016/j.fochx.2026.104518

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104518

Keywords: lupin protein isolate, Maillard reaction, galacto-oligosaccharides, microwave-assisted extraction, protein glycation, emulsifying properties, foaming capacity, gut microbiota, short-chain fatty acids, prebiotics, plant protein, Food Chemistry: X

The research team, led by Bekri Melka Abdo and Sung-Hyen Lee of the Rural Development Administration’s National Institute of Crop and Food Science, set out to test a deceptively simple question: does the liquid used to presoak onion skin matter? Presoaking is usually dismissed as a washing step, a necessary bit of hygiene before the real work of extraction begins. But the authors argue that soaking can hydrate plant tissue, alter cell wall permeability, and change how soluble compounds diffuse out of the matrix. In other words, the soak itself may be a controllable processing variable—one that food manufacturers could tune to steer the chemistry of the final ingredient.

To probe this idea, the team obtained dried inner skins from conventionally grown yellow onions of a single hybrid cultivar lineage, traced through seed import records to a Dutch-bred variety and farmed in the Mungyeong and Yecheon regions of Gyeongsangbuk-do. The skins were soaked at room temperature in one of five solutions: tap water, 5% vinegar, 1% citric acid, a 1:1 mixture of vinegar and citric acid, or 0.3% hydrogen peroxide. Each soak lasted just four, eight, or twelve minutes—a deliberately narrow window chosen to see whether even minimal预处理 could shift the outcome. After rinsing, drying, and grinding, the powders were extracted in two contrasting systems: methanol, a laboratory reference solvent prized for pulling out flavonol aglycones, and hot water at 95°C, a route compatible with food production.

The results, analyzed by two-way ANOVA with Fisher’s least significant difference comparisons, showed a striking pattern: the identity of the soaking solution had a significant main effect on nearly every major parameter, while the duration of soaking—within that tight 4-to-12-minute range—mattered far less. Solution chemistry, not time, was the dominant lever. Citric acid and the vinegar–citric acid mixture produced the highest extraction yields, boosting total solids recovery to roughly 10.5–10.7% in both solvent systems, compared with about 5.8–7% for plain water. But the researchers caution that yield alone is a misleading metric. The acid-soaked samples recovered more non-phenolic material, diluting the phenolic density of the extracts rather than enriching them.

Total phenolic content, measured by the Folin–Ciocalteu assay and expressed as gallic acid equivalents, reached nearly 491 mg/g in water-soaked methanol extracts—the highest of any condition—while dropping to under 400 mg/g in the citric-acid group. The picture flipped, however, when the team turned to hot water. Here, peroxide-soaked skins yielded the strongest total flavonoid content at 918 mg quercetin equivalents per gram, and the highest quercetin glycoside yields in both solvent systems. Targeted UPLC–PDA quantification confirmed that quercetin, the dominant flavonol of onion skin, partitioned overwhelmingly into methanol—accounting for over 61% of the ion signal in the reference extract—while hot-water extracts were richer in protocatechuic acid and other polar constituents. High-resolution UHPLC–Orbitrap mass spectrometry revealed that the two solvents were not simply recovering different amounts of the same chemistry; they were generating compositionally distinct fractions.

Antioxidant performance tracked this compositional divergence. Using the DPPH radical-scavenging assay, the team calculated IC₅₀ values by four-parameter nonlinear regression and found that peroxide-presoaked extracts showed some of the most favorable radical-scavenging potency, alongside vinegar-treated samples. Exploratory contour plots suggested combined process–response patterns linking solution pH, soak duration, and antioxidant strength, though the authors are careful to note that the soaking solutions differed chemically as well as in pH, so the plots describe trends within the tested range rather than a universal pH optimum. The team emphasizes that assays like DPPH and Folin–Ciocalteu measure electron-transfer chemistry in a plate, not physiological efficacy in a body—useful for comparing treatments, but not proof of health benefits.

To add a biological dimension, the researchers screened representative extracts in RAW 264.7 macrophage cells, measuring metabolic activity with an MTS assay and nitric oxide production indirectly through nitrite accumulation via the Griess reaction. The extracts did not markedly reduce metabolic viability at the tested concentrations of 125 to 500 μg/mL, and presoaking-dependent differences in nitrite accumulation were observed within each extract type. Yet the authors are explicit about the limits: the extracts were tested without an inflammatory challenge such as lipopolysaccharide co-treatment, the two extract types were compared at different doses and durations, and nitrite levels cannot be classified as beneficial or harmful without a defined inflammatory model. The macrophage data are presented as hypothesis-generating screening, not evidence of immunological effect.

The practical implications reach into the growing field of food by-product valorization. Onion skin is a concentrated reservoir of quercetin and related flavonoids with well-documented antioxidant relevance, and converting it into a standardized food ingredient aligns with circular-economy and biorefinery principles. This study suggests that process designers should choose soaking solutions according to their target profile: acids to maximize mass yield, neutral water to preserve phenolic density in organic extraction, or carefully controlled mild oxidation to enhance hot-water flavonoid recovery. Because hot water is the route most compatible with industrial food processing, the finding that presoaking can steer hot-water extract composition is particularly relevant to anyone hoping to upcycle onion waste at scale.

The researchers are equally clear about what their work does not establish. The 0.3% hydrogen peroxide condition was an experimental oxidative treatment, not a food-ready process; residual peroxide, oxidation products, removal efficiency, and regulatory compliance would all need validation before any practical use. The study also did not measure structural changes in the skin matrix, so the mechanism behind the peroxide effect—whether enhanced accessibility or chemical transformation—remains unassigned. Translation to industry, the authors write, will require confirmation across harvests and commercial lots, pilot-scale mass and energy balances, stability and sensory testing, food-matrix performance trials, safety assessment, and techno-economic analysis. What the study does deliver is a framework: a demonstration that a step as ordinary as a few minutes of soaking, guided by the right chemistry and matched to the right solvent, can meaningfully reshape the value recovered from one of the world’s most abundant vegetable waste streams.

Subject of Research: How brief presoaking treatments modulate phytochemical recovery, antioxidant capacity, and macrophage responses of onion skin extracts

Article Title: Simple presoaking modulates phytochemical recovery, antioxidant capacity, and macrophage responses of onion skin extracts

Article References: Abdo, B. M., Song, D., Kang, H. J., Im, J. Y., Hwang, I.-G., Choi, A. J., Kwon, S., & Lee, S.-H. (2026). Simple presoaking modulates phytochemical recovery, antioxidant capacity, and macrophage responses of onion skin extracts. Food Chemistry: X, 39, Article 104402. https://doi.org/10.1016/j.fochx.2026.104402

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104402

Keywords: onion skin, phytochemicals, quercetin, antioxidant activity, food waste valorization, presoaking, hot water extraction, flavonoids, RAW 264.7 macrophages, circular economy, Food Chemistry: X, phenolic compounds

Orally disintegrating films, or ODFs, are thin sheets that melt rapidly against the oral mucosa, releasing their payload for absorption without the need to swallow. Conventional ODFs rely almost exclusively on hydrophilic polysaccharides such as pullulan, hydroxypropyl methylcellulose, and pregelatinized starch, which disintegrate quickly; published examples include hydroxypropyl cellulose films that vanish in water in about 12.5 seconds and hydroxypropyl methylcellulose formulations that break down in roughly 43 seconds. But these matrices carry little nutritional value, and protein hydrolysate alternatives are prohibitively expensive. Soy protein isolate, a widely available and inexpensive plant protein with excellent film-forming ability and a rich amino acid profile, seemed like an obvious candidate, except that its dense, flexible molecular packing causes films to disintegrate sluggishly in water, sometimes lagging far behind their polysaccharide competitors.

The team’s answer was β-cyclodextrin, a cyclic oligosaccharide with a hydrophobic interior cavity and a hydrophilic, hydroxyl-covered exterior. Cyclodextrins are workhorses in food and pharmaceutical science, used to emulsify, solubilize, mask unpleasant flavors, and protect sensitive bioactive compounds. Previous work by some of the same authors had shown that β-cyclodextrin could accelerate the disintegration of soy protein films by disrupting the tight packing of protein chains. The new study asked whether the molecule could do double duty: remodel the protein network for rapid release while also protecting ergothioneine, a sulfur-containing antioxidant first isolated in 1909 from the fungus Claviceps purpurea and produced by edible fungi and cyanobacteria.

Ergothioneine was a demanding guest. Its unusually low redox potential of −60 millivolts makes it resistant to autoxidation, and studies have shown it outperforms glutathione at scavenging hydroxyl radicals, peroxyl radicals, and singlet oxygen. Yet antioxidant activity in ergothioneine-containing systems is known to decline during thermal processing and storage, likely through oxidative degradation. The researchers cast films by dissolving 2.0 grams of soy protein isolate in water at 75 degrees Celsius, adding 10 milligrams of ergothioneine, 0.7 grams of D-sorbitol as a plasticizer, and β-cyclodextrin at 0, 5, 10, and 15 percent of the dry protein weight, then drying the solutions in Petri dishes at 40 degrees Celsius for eight hours.

Microscopy revealed how dramatically the additive reshaped the material. The pristine soy protein film was rough and inhomogeneous, riddled with micropores and aggregated particulate domains, while adding ergothioneine alone smoothed the surface, apparently by promoting the unfolding of protein polypeptide chains. The real transformation came at 10 percent β-cyclodextrin, where the films displayed an extremely smooth, dense, defect-free surface organized into a continuous reticular network. The authors attribute this to hydrogen bonding between the cyclodextrin’s abundant hydroxyl groups and the protein network, which suppresses pore formation during drying. At 15 percent, however, the strategy backfired: bright, angular crystalline aggregates appeared across the surface, evidence that excess cyclodextrin had exceeded its solubility limit and phase-separated into β-CD-rich crystalline domains, shattering the structural continuity of the protein matrix.

Those structural changes translated directly into performance. The water contact angle, a measure of surface wettability, fell from 63.77 degrees in the control film to 36.28 degrees at 10 percent cyclodextrin, reflecting a far more hydrophilic surface that welcomes water penetration. Tensile strength climbed from 10.37 megapascals in the control to 12.15 megapascals at the optimal loading, and elongation at break rose from 3.462 to 4.376 percent, meaning the films became both stronger and more flexible. Then came the headline result: in vitro disintegration time dropped from 31.67 seconds in the control to 15.46 seconds at 10 percent cyclodextrin, a 45 to 52 percent improvement across the cyclodextrin-containing formulations, comfortably meeting the sub-60-second benchmark for fast-disintegrating films. Intriguingly, the 15 percent formulation showed no significant further gain, because its added thickness lengthened the path water had to travel, canceling out its extra hydrophilicity.

The loading data told a similarly encouraging story. High-performance liquid chromatography showed that ergothioneine loading efficiency rose from 66.83 percent in films without cyclodextrin to 76.33 percent at the 10 percent level, with loading capacity peaking at 2.16 micrograms per milligram of film. Relative standard deviations across replicate films stayed below 4 percent, confirming that the solvent casting method produces reproducible, uniformly dosed films. Each standard 15-by-15-millimeter dosing unit carried about 16.21 micrograms of ergothioneine in the optimal formulation. Surface pH values for all films ranged from 5.55 to 6.48, safely within the range tolerated by oral tissue, and mucoadhesive forces were essentially unchanged at moderate additive levels, reaching 0.69 newtons only in the phase-separated 15 percent formulation, where crystalline protrusions increased contact area.

The protective half of the dual function emerged under stress. The team sealed films in ordinary plastic bags and stored them for 28 days at 40 degrees Celsius, 75 percent relative humidity, under continuous fluorescent light to simulate accelerated oxidative aging. Films containing ergothioneine alone watched their DPPH radical scavenging activity collapse from 83.47 percent on day zero to 40.86 percent by day 28, with ABTS activity falling in parallel from 85.21 to 41.74 percent. Films with 10 percent cyclodextrin retained 60.57 percent DPPH activity and 60.68 percent ABTS activity over the same period, significantly better than every other formulation. Spectroscopic characterization supported the mechanism: X-ray diffraction showed the amorphous protein film acquiring the characteristic crystalline peaks of β-cyclodextrin, while Fourier-transform infrared spectroscopy revealed strengthened hydrogen bonding bands at 3288, 1641, and 1537 reciprocal centimeters, along with new peaks marking the cyclodextrin skeleton. Thermogravimetric analysis showed the maximum decomposition temperature rising steadily with cyclodextrin loading, from 300.28 degrees Celsius in the control to a peak of 314.63 degrees, confirming a more thermally robust composite.

The authors are careful about how far the interpretation can go. Because the antioxidant assays measure total radical scavenging of the entire film matrix rather than residual ergothioneine concentration directly, and because no inclusion complex between cyclodextrin and ergothioneine was demonstrated, the improved retention may reflect reduced oxidative exposure through intermolecular interactions and a denser matrix rather than the specific stabilization of individual ergothioneine molecules. The disintegration tests also used distilled water rather than simulated saliva, and all evaluations were in vitro. Future work employing HPLC or LC-MS quantification of ergothioneine, phase-solubility analysis, differential scanning calorimetry, and two-dimensional NMR is needed to pin down the molecular fate of the antioxidant during storage.

Even with those caveats, the implications are considerable. The study breaks the disintegration barrier that has kept soy protein out of serious consideration for orally disintegrating films, and it does so with a cheap, food-grade cyclodextrin that simultaneously improves mechanical strength, thermal stability, and antioxidant retention. For the food and pharmaceutical industries, the platform suggests a practical route to delivering sensitive bioactive compounds, from ergothioneine to other oxidation-prone nutraceuticals, in a fast-dissolving, plant-protein-based format that adds nutritional value instead of diluting it. If longer-term storage studies and in vivo safety testing bear out the accelerated results, the humble soybean may find itself at the leading edge of oral thin-film technology, one 15-second melt on the tongue at a time.

Subject of Research: Development of soy protein isolate-based orally disintegrating films using β-cyclodextrin to enhance disintegration and protect ergothioneine

Article Title: Development of soy protein isolate-based orally disintegrating films: The dual role of β-Cyclodextrin in enhancing disintegration performance and ergothioneine stability

Article References: Zhou, Y., Du, X., Lv, C., Tian, Y., Guo, S., Guo, Z., & Wang, Z. (2026). Development of soy protein isolate-based orally disintegrating films: The dual role of β-Cyclodextrin in enhancing disintegration performance and ergothioneine stability. Food Chemistry: X, 39, Article 104451. https://doi.org/10.1016/j.fochx.2026.104451

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104451

Keywords: orally disintegrating films, soy protein isolate, β-cyclodextrin, ergothioneine, oral drug delivery, antioxidant stability, film disintegration, hydrogen bonding, plant protein, Food Chemistry: X, bioactive compound protection, solvent casting