The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O₂) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O₂ concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0–60% O₂ (p < 0.05), but deteriorated at 80% O₂ level. As the concentration of O₂ increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in β-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O₂ in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O₂ concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.

This study explored the sustainable valorization of fruit waste extracts from sugarcane bagasse (SB), banana peel (BP), and watermelon rind (WR) for Euglena gracilis biomass and β-1,3-glucan production. The extracts were prepared using water extraction (WE), high-temperature and pressure treatment (HTP), and dilute sulfuric acid treatment (DSA). The DSA-treated extracts consistently yielded the best results. E. gracilis cultured in SB-DSA showed the highest cell density with a 2.08-fold increase compared to the commercial HUT medium, followed by BP-DSA (1.35-fold) and WR-DSA (1.70-fold). Photosynthetic pigment production increased significantly, with chlorophyll a yield being highest in SB-DSA (1.90-fold increase). The chlorophyll a/b ratio and total carotenoid content also improved, indicating enhanced light-harvesting capacity and photoprotection. Photosynthetic efficiency, measured by chlorophyll fluorescence, notably improved. The maximum quantum yield of PSII (Fv/Fm) increased by up to 25.88% in SB-DSA, suggesting reduced stress and improved overall photosynthetic health. The potential photochemical efficiency (Fv/F0) showed even greater improvements: up to 40.53% in SB-DSA. Cell morphology analysis revealed larger cell aspect ratios, implying a more active cellular physiological state. β-1,3-glucan yield also increased by 23.99%, 12.92%, and 23.38% in SB-DSA, BP-DSA, and WR-DSA, respectively. This study demonstrates the potential of pretreated fruit waste as a cost-effective and sustainable medium for E. gracilis cultivation, offering the dual benefits of waste valorization and high-value compound production. These findings contribute to the development of more efficient biorefinery processes and align with the circular economy principles in food biotechnology.

Whey protein hydrolysate (WPH) has made a breakthrough in inhibiting oxidative deterioration and improving the quality of meat products during storage. Based on our previous study of extracting the most antioxidant active fraction I (FI, the molecular weight < 1 kDa) from whey protein hydrolysates of different molecular weights, the present study continued to delve into the effects of WPH with fraction I on the structure and function of myofibrillar proteins (MP) in ground pork during the freeze–thaw (F-T) cycles. With the number of F-T cycles raised, the total sulfhydryl content, the relative contents of α-helix, Ca²⁺-ATPase activity, K⁺-ATPase activity, solubility, emulsion activity index (EAI), and emulsion stability index (ESI) of MP gradually decreased. Conversely, the carbonyl content and the relative content of random curl showed an increasing trend. In particular, the damage to the structure and the function of MP became more pronounced after three F-T cycles. But, during F-T cycles, FI stabilized the structure of MP. Compared to the control group, the 10% FI group showed a remarkable improvement (p < 0.05) in the total sulfhydryl content, Ca²⁺-ATPase activity, K⁺-ATPase activity, solubility, EAI and ESI after multiple F-T cycles, suggesting that 10% FI could effectively inhibit protein oxidation and had the influence of preserving MP function properties. In conclusion, WPH with fraction I can be used as a potential natural antioxidant peptide for maintaining the quality of frozen processed meat products.

Euglena gracilis’s mixotrophic metabolism offers biotechnological potential. This study investigated how glucose, sodium acetate, ethanol, and propanetriol regulate its growth, photosynthesis, and paramylon production. All carbon sources boosted paramylon yield versus photoautotrophic controls. Ethanol and glucose were both highly effective, supporting the highest biomass accumulation (5.71 and 4.42-fold increases, respectively) and paramylon content without a significant difference between them. Ethanol supplementation enhanced chlorophyll b via coupled TCA cycle/glyoxylate shunt activity, while glucose showed the strongest tendency for high paramylon and the highest carotenoid content (13.36-fold higher). Sodium acetate triggered alkaline stress (pH 8.5), suppressing pigments and inducing spherical cells. Propanetriol reduced biomass but enhanced PSII efficiency (Fv/Fm). These results demonstrate carbon source-driven metabolic partitioning: ethanol and glucose both excel in promoting growth and storage, while additionally directing carbon toward chlorophyll b or carotenoids, respectively. These findings enable targeted bioprocess optimization: selection between ethanol or glucose can be based on the value of co-products, advancing E. gracilis as a sustainable cell factory.

This study investigated the impact of various thermal processing methods—steaming, boiling, frying, and baking—on the volatile organic compounds (VOCs) in sweet potato (Ipomoea batatas L.) brandy using gas chromatography–ion mobility spectrometry (GC-IMS). Yanshu No. 25 sweet potatoes, recognized for their high levels of mucin protein and soluble sugars, were employed for the fermentation of the brandy. GC-IMS analysis generated three-dimensional spectrograms, which revealed distinct VOC profiles depending on the processing method used. Notably, steaming, frying, boiling, and baking significantly altered the VOC composition, imparting unique flavor characteristics. A total of 37 VOCs were identified, with esters being the predominant class, contributing to fruity and floral notes in the brandy. Principal component analysis (PCA) and Euclidean distance-based fingerprint similarity analysis further differentiated the VOC profiles, highlighting the essential role of processing techniques in flavor development. These findings provide a foundation for future research aimed at optimizing processing methods to create specific aromatic profiles in sweet potato brandy.