A research team led by Tingchen Si and colleagues, publishing in Food Chemistry: X, has now systematically tested two contrasting pretreatment strategies to solve this dilemma: steam explosion and heat curing. Their goal was ambitious. Rather than simply stabilizing the mushroom powder, they wanted to know whether these treatments could actively upgrade it, enhancing flavor, refining particle structure, and improving compatibility with wheat dough so that the powder could be folded into noodles without wrecking the gluten network. The work combined electronic nose profiling, gas chromatography-ion mobility spectrometry, free amino acid quantification, infrared spectroscopy, particle size analysis, electron microscopy, and a battery of dough rheology tests, offering one of the most complete pictures yet of how processing reshapes a functional mushroom ingredient.

Steam explosion is a dramatic technique by any standard. Dried mushroom pieces were rehydrated for twelve hours, then loaded into a pressurized chamber where saturated steam at 0.6, 0.9, or 1.2 megapascals was held for five minutes before an abrupt release of pressure. In that instant, stored thermal energy converts into mechanical energy, tearing apart cell walls and fibrous architecture. Heat curing took a gentler path: ground mushroom powder spread in thin layers was heated at 90, 100, 110, or 120 degrees Celsius for fifteen minutes each. The two methods thus represent opposite philosophies, one delivering a violent mechanical shock in seconds, the other applying controlled, sustained heat.

The amino acid results were striking. Steam explosion at 0.9 megapascals more than doubled total free amino acids, raising them from 26.54 milligrams per gram in untreated powder to 66.89 milligrams per gram. Umami amino acids such as glutamic and aspartic acid, the molecular backbone of savory taste, nearly doubled, while sweet amino acids climbed almost threefold. The mechanism is physical as much as chemical: the pressure release disrupts intracellular matrices and releases pre-existing free amino acids, while high-temperature, high-pressure conditions denature proteins, unfold peptide chains, and weaken non-covalent interactions, making proteins vulnerable to degradation into smaller nitrogenous compounds. Crucially, the short residence time limits the Maillard reaction, so amino acids are liberated faster than they are consumed. Pressure mattered enormously. At 0.6 megapascals the disruption was insufficient; at 1.2 megapascals excessive thermal exposure drove secondary degradation, reducing net accumulation. The 0.9 megapascal condition hit the sweet spot.

Heat curing told a different story. At 90 degrees Celsius, total free amino acids rose modestly to 29.92 milligrams per gram, but every additional ten degrees pushed them sharply downward, falling to just 13.02 milligrams per gram at 120 degrees. The culprit is the Maillard reaction, which accelerates at higher temperatures as amino acids react with reducing sugars to form melanoidins and heterocyclic compounds, consuming precisely the umami amino acids that give mushrooms their appeal. Prolonged high heat can also trigger deamidation and oxidative degradation of asparagine and glutamine, while cellular autolysis activates endogenous proteases that further erode the free amino acid pool. The lesson is that heat curing rewards restraint: gentle temperatures preserve, aggressive ones destroy.

Aroma analysis revealed equally distinctive fingerprints. Gas chromatography-ion mobility spectrometry detected 106 volatile organic compounds across the samples, including 17 esters, 15 aldehydes, 14 alcohols, 11 ketones, and 6 pyrazines. Untreated powder retained a natural, plant-like profile dominated by pentanal, octanal, and ethyl acetate, with fruity and green notes. Heat-cured powder developed elevated concentrations of butanal, 3-methylbutanal, and various esters, producing sweet, chocolate-like fruity aromas alongside pungent sulfides. Steam-exploded powder underwent the most dramatic transformation: high-temperature, high-pressure conditions promoted Maillard chemistry, generating roasted, nutty pyrazines such as 2-ethyl-3-methylpyrazine alongside characteristic mushroom ketones like 1-octen-3-one. Principal component analysis confirmed that the volatile profiles of the treated and untreated powders were clearly separable, with the first two components explaining 94 percent of the variance.

Structural measurements reinforced why these powders behave differently in dough. Steam-exploded powder had the smallest median particle size, at 136.96 micrometers compared with 187.99 micrometers for untreated powder, because the instantaneous pressure release shatters cell walls and fibrous networks into finer fragments. Scanning electron microscopy showed the steam-exploded particles with loosened, disrupted microstructure and smoother surfaces, while untreated and heat-cured powders displayed wrinkled, compact, rough textures. Fourier transform infrared spectroscopy, meanwhile, showed that the fundamental functional groups, including hydroxyl stretches near 3432 per centimeter and carbonyl bands near 1640 per centimeter, were broadly retained across all treatments, meaning the chemical identity of the mushroom matrix survived even as its physical architecture was rebuilt.

The decisive test came when the powders were blended into wheat flour at substitution levels of 1, 3, 5, and 7 percent. Mixolab thermomechanical analysis showed that untreated mushroom powder steadily degraded dough performance, cutting stability time from 7.95 minutes to 3.60 minutes at 7 percent substitution as the dilution of gluten-forming proteins weakened the cohesive network. Steam-exploded powder behaved remarkably differently: stability time barely changed, holding at 7.35 minutes even at 7 percent substitution, apparently because the modified fiber and polysaccharide components disperse well within the gluten-starch matrix and interact constructively with gluten proteins. Water absorption rose in all formulations, reflecting the mushroom powder’s strong water-holding capacity, but the processed powders demanded less added water than the untreated one. The 5 percent substitution level emerged as the optimal balance, enhancing functional contribution while preserving gluten network integrity.

Rheological and pasting measurements added further nuance. All composite doughs exhibited elastic-dominant viscoelastic behavior, with storage modulus exceeding loss modulus across the tested frequency range and loss tangent values below one, indicating solid-like structures suitable for noodle processing. Rapid Visco Analyzer results showed that peak viscosity declined with mushroom addition, most sharply for heat-cured powder, whose water-hungry fiber competes with starch for moisture and restricts granule swelling. Steam-exploded powder, by contrast, released soluble polysaccharides that partially compensated for this restriction, keeping peak viscosity statistically indistinguishable from the control. Setback values, which track starch retrogradation during cooling and predict staling, fell in all mushroom-supplemented samples, suggesting the treated powders could help noodles stay fresher longer.

Low-field nuclear magnetic resonance provided the final piece of the puzzle by tracking water mobility inside the dough. All samples showed three proton populations corresponding to bound, partially immobilized, and free water, but the steam-exploded and heat-cured formulations shifted the transverse relaxation times of the immobilized water fraction to longer values, indicating increased water mobility and weaker water-matrix interactions. This redistribution, likely tied to the porous microstructure of the treated fibers, can improve gluten hydration and dough softness while influencing starch retrogradation. Taken together, the findings sketch a practical decision framework for food manufacturers: steam-exploded powder at 0.9 megapascals suits flavor-focused, high-dispersibility applications such as noodles, while 90-degree heat-cured powder, with its enhanced sweet aroma compounds and preserved organic acids, fits bakery and steamed bread products where elasticity and aroma matter most. Both routes turn a perishable, flavor-fragile mushroom into a stable, functional ingredient, and both leave the gluten network largely intact at moderate substitution levels, bringing wine-cap mushroom noodles a significant step closer to the supermarket shelf.

Subject of Research: Effects of steam explosion and heat curing pretreatments on the physicochemical properties of Stropharia rugosoannulata powder and wheat dough quality

Article Title: Effects of steam explosion and heat curing on the physicochemical properties of Stropharia rugosoannulata powder and dough quality

Article References: Si, T., Arshad, A., Intizar, A., Rong, Q., Liu, S., Sun, Y., Li, X., Gao, K., & Liang, J. (2026). Effects of steam explosion and heat curing on the physicochemical properties of Stropharia rugosoannulata powder and dough quality. Food Chemistry: X, 39, Article 104502. https://doi.org/10.1016/j.fochx.2026.104502

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104502

Keywords: wine-cap mushroom, Stropharia rugosoannulata, steam explosion, heat curing, free amino acids, umami, flavor compounds, dough rheology, noodles, dietary fiber, LF-NMR, food processing

The review begins by distinguishing the vocabulary of flavor science. Flavor encompasses the overall sensory perception of food, including taste, touch, smell, sight, and even sound, while aroma refers specifically to the odor detected by the olfactory system. The compounds responsible range from naturally occurring phenolics, terpenoids, alcohols, esters, ketones, and pyrazines found in essential oils, spices, and citrus peels, to synthetic molecules engineered to mimic smoky, citrus, fruity, buttery, or caramel notes. Many of these molecules carry bonus biological activity, including antioxidant, anticancer, anti-inflammatory, and immune-boosting properties. But their volatility is their undoing. In products such as cookies and bread, flavors can be lost during baking or develop off-notes, which is why manufacturers increasingly turn to encapsulation, the practice of wrapping active compounds in protective carrier materials that shield them from degradation, delay their release, prevent oxidation, and ultimately enhance the eating experience.

Encapsulation operates across macro, micro, and nano scales, from capsules larger than 5,000 micrometers down to structures of just 1 to 100 nanometers. While the microscale dominates the food industry today, the review highlights growing evidence that nanoencapsulation offers superior stability, better controlled release, enhanced solubility in liquids, and improved penetration through biological barriers. The conventional toolbox includes physicochemical methods such as coacervation and emulsification, physicomechanical methods such as spray drying and freeze drying, and chemical methods based on polymerization and cross-linking. Each technique produces capsules that differ in size, morphology, release profile, and stability, and the authors stress that no single method is universally superior. Selection depends on the chemistry of the flavor compound, the carrier material, the intended food application, economic constraints, and production scale rather than encapsulation efficiency alone.

Spray drying remains the most widely applied industrial technique, prized for its simplicity, low cost, scalability, and high throughput. In this process, a flavor is dissolved or dispersed in a carrier matrix, atomized into a heated drying chamber, and rapidly converted into spherical particles, often under nitrogen to prevent oxidation. The review cites strawberry flavor encapsulation achieving 85 percent efficiency using maltodextrin, modified starch, and gum arabic at an inlet temperature of 190 degrees Celsius, yielding microcapsules with roughly 90 percent solubility. Yet the method has a critical weakness: retention of volatiles varies enormously with molecular weight. High-carbon volatiles may retain up to 95 percent of their aroma, while low-molecular-weight compounds such as acetaldehyde may retain as little as 20 percent, creating potential inconsistencies between liquid and powdered flavor versions. Powder adhesion to equipment and thermal reactions further complicate the picture, and most studies remain at laboratory scale with limited data on real processing conditions and long-term storage.

The cooler alternatives each carry their own trade-offs. Spray chilling, which solidifies lipid-encapsulated flavors in a cooling chamber at 34 to 42 degrees Celsius, minimizes thermal degradation and suits heat-sensitive compounds, but it is restricted to lipid-based carriers and requires flavors to remain stable at the lipid melting point. Applications include coating the potent aroma compound 2-acetyl-1-pyrroline with paraffin for stability and masking bitter plant extracts for dark chocolate. Freeze drying, which removes water by sublimation, excels at preserving heat-sensitive compounds and creates porous structures that facilitate controlled release, but its high energy consumption, long processing times, and cost confine it largely to high-value products such as coffee and spices. In a comparative study of chamomile extract, freeze drying better preserved total polyphenol content, yet spray drying achieved higher encapsulation efficiency of about 90 percent versus 84 percent, underscoring that the optimal choice depends on the core material and the priorities of the manufacturer.

Coacervation occupies a middle ground, forming micro- or nanocapsules by depositing proteins or polysaccharides around flavor droplets in an emulsion. It can encapsulate both hydrophilic and hydrophobic compounds at room temperature, protecting heat-sensitive flavors and achieving impressive efficiencies, with recent reports of cinnamon extract encapsulation in alginate reaching up to 97 percent while masking undesirable flavors. However, the process is notoriously sensitive to pH, ionic strength, polymer molecular weight, and solvent properties, which can produce variable particle sizes, aggregation, and elevated costs. The review notes that systematic studies of how the molecular characteristics of flavor compounds, such as electrical charge and hydrophobicity, influence coacervate formation remain limited, and calls for predictive models to improve reproducibility and industrial applicability.

Against this backdrop, electrospinning has emerged as the review’s most compelling alternative. The technique applies a high-voltage electrostatic field to a polymer solution containing the flavor, stretching it into elongated fibrous structures with diameters ranging from nanometers to micrometers, high surface-area-to-volume ratios, and interconnected porosity. Because the process operates under mild conditions without high temperatures, pressure, or harsh chemicals, it preserves the structural and sensory integrity of volatile compounds. Two advanced variants, emulsion electrospinning and coaxial electrospinning, produce core-shell fibers in which the aromatic compound is physically confined to the inner core and surrounded by an outer polymer layer, reducing contact with the environment and limiting burst release. Shell thickness, core-to-shell flow ratio, and polymer hydrophobicity can be tuned to precisely control release kinetics. Reported encapsulation efficiencies are striking: thyme essential oil in potato starch nanofibers reached 99 percent, saffron in gelatin reached 96 percent, and thymol in pullulan-whey composites reached 87 percent with release targeted to the small intestine.

The practical applications documented in the review read like a preview of future food packaging. Electrospun polyvinyl alcohol nanofibers loaded with laurel and rosemary essential oils reduced lipid oxidation in chicken breast fillets by up to 68 percent while improving microbial and color stability. Gelatin-chitosan nanofibers carrying thyme essential oil showed bactericidal activity against Clostridium perfringens in sausages, suggesting a viable alternative to nitrite. Polycaprolactone nanofibers incorporating lemon essential oil and a metal-organic framework extended the shelf life of red meat at 4 degrees Celsius by up to 18 days, and a bilayer acorn starch-zein film with cinnamon essential oil extended the shelf life of rainbow trout fillets by six days while cutting lipid oxidation by 44 percent. Perhaps most intriguingly, stimulus-responsive systems are now being designed to release flavors only when triggered by light, pH shifts, temperature, humidity, or even the spoilage enzymes secreted by contaminating microbes, enabling packaging that actively responds to the state of the food it protects.

Significant hurdles remain before electrospinning can displace conventional methods at scale. Production throughput is low, scalability is difficult, the range of food-grade solvents is limited, and the process is sensitive to parameters such as voltage, viscosity, humidity, and flow rate, with even small changes altering fiber morphology and release kinetics. Regulatory approval of a polymer in bulk form does not automatically extend to its nanofibrous form, because electrospinning can alter conformation, crystallinity, surface area, and degradation behavior, and data on gastrointestinal fate and long-term toxicity of electrospun nanostructures are sparse. The review concludes that electrospinning should be viewed as a complementary technology that expands the encapsulation toolkit rather than a universal replacement, and it calls for validation in real food matrices, predictive computational models including machine learning, greener solvent systems such as natural deep eutectic solvents, and comprehensive sensory and consumer studies. If those challenges are met, the fibers now spinning in laboratories could soon deliver aroma exactly when and where the palate demands it.

Subject of Research: Controlled-release encapsulation technologies for aromatic and flavor compounds in food systems

Article Title: Recent Advances in Technologies for the Controlled Release of Aromatic Compounds: From Encapsulation to Electrospinning

Article References: Mojarad, M., Shiravani, Z., Abedi, E., Jafarpour, D., Sayadi, M., & Bagher Hashemi, S. M. (2026). Recent Advances in Technologies for the Controlled Release of Aromatic Compounds: From Encapsulation to Electrospinning. Current Research in Food Science, Article 101586. https://doi.org/10.1016/j.crfs.2026.101586

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101586

Keywords: encapsulation, electrospinning, flavor compounds, aromatic compounds, controlled release, spray drying, freeze drying, coacervation, nanofibers, essential oils, food packaging, food science