Wheat serves as a vital initial inoculum for high-temperature Daqu microbiota, yet the functional roles of its indigenous microorganisms in Daqu quality formation remain poorly understood. Here, high-temperature Daqu was prepared using sterilized (Daqu_S) and non-sterilized wheat (Daqu_T). Combining high-throughput sequencing, flavoromics, and metabolomics, this study investigated how wheat-surface microorganisms shape Daqu microecology, community assembly, and flavor metabolism. Wheat-surface sterilization removed most of the epiphytic microbes and reshaped microbiome succession, whereby Kroppenstedtia and Thermoascus declined while Saccharopolyspora, Weissella, and Thermomyces were enriched. Co-occurrence network and neutral community model analyses revealed that sterilization increased network scale but decreased the proportion of positive correlations, and Daqu_S displayed a greater contribution of stochastic assembly processes. OPLS-DA models identified 19 differential volatiles (of 76 total) and 30 differential non-volatile metabolites (of 252 total). Daqu_T accumulated key amino-acid precursors and signature pyrazines including tetramethylpyrazine and trimethylpyrazine, whereas Daqu_S showed flavor imbalance with abnormal accumulation of lipids, amines, and aromatics. Multi-omics analysis indicated that bacteria enriched in Daqu_T encoded predicted key enzymes (e.g., EC:2.2.1.6, EC:1.4.1.2), which were putatively critical for carbon-nitrogen metabolism and characteristic pyrazine biosynthesis. Collectively, wheat-surface microorganisms appear to underpin microecological establishment, metabolite accumulation, and typical flavor development in high-temperature Daqu, offering new insights for targeted Daqu quality modulation.
Leaf-vegetable sweetpotato is highly susceptible to postharvest dehydration, yellowing, and senescence, which severely limits its commercial value and shelf life. Ectoine (ECT), a natural compatible osmolyte with excellent water-binding and stress-protective properties, has attracted increasing attention in biological stress protection, however, its potential role in postharvest preservation of leafy vegetables remains unclear. This study investigated the effects of ECT treatment on postharvest quality deterioration of leaf-vegetable sweetpotato and the underlying mechanisms. The results showed that ECT treatment significantly delayed wilting, reduced weight loss, and maintained firmness and visual quality during storage. Magnetic resonance imaging analysis presented that ECT improved water retention capacity and alleviated water migration, indicating the maintenance of cellular water homeostasis. Meanwhile, ECT effectively suppressed chlorophyll degradation and carotenoid loss, thereby delaying yellowing. Ultrastructural observations demonstrated that ECT preserved chloroplast integrity and maintained cellular organization during storage. Moreover, ECT regulated reactive oxygen species (ROS) homeostasis by reducing excessive accumulation of superoxide anion and hydrogen peroxide, thereby limiting membrane lipid peroxidation. Additionally, ECT enhanced both non-enzymatic antioxidant capacity and antioxidant enzyme activities, including superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase, contributing to improved redox balance. Collectively, this study revealed that ECT acted as a multifunctional postharvest protectant by coordinating cellular water status, chloroplast stability, and antioxidant defense, thus providing a promising strategy for extending the shelf life and maintaining the quality of leaf-vegetables.
This study investigated the effects of κ-carrageenan (CG) and psyllium husk (PH) on the gelation and physicochemical properties of myofibrillar protein (MP) extracted from spent laying hens. A 3 × 4 factorial design was used, with three CG levels (1, 1.5, and 2% w/w) combined with four PH levels (0, 1, 2, and 3% w/w), resulting in three treatments containing MP and CG without PH and nine treatments containing MP, CG, and PH. At each CG concentration, formulations containing 1–3% PH exhibited significantly higher water-holding capacity and generally denser, more homogeneous gel structures than the corresponding 0% PH formulations. The formulation containing 1.5% CG and 3% PH exhibited the highest gumminess and chewiness and was among those with the highest hardness, whereas formulations containing 1.5% CG with 1–2% PH exhibited the greatest gel strength. All composite gels exhibited predominantly elastic behavior; however, gel strength decreased at higher combined hydrocolloid concentrations, suggesting interference with gel network organization. Overall, the gel properties depended on the CG-to-PH ratio, highlighting the importance of formulation optimization for the utilization of spent hen meat in value-added poultry products.
