This study examined the effect of triple-frequency ultrasound treatment (TFUT)-assisted lactic acid bacteria (LAB-L. plantarum and L. helveticus fermentation for 24-h and 48-h) on the chemical, structural, morphological, metabolic, and sensory properties of rice lees (RL). Ultrasonicated-assisted RL fermented with L. helveticus (URLH-48) had the greatest total phenolic contents (TPC) (112.1 mg GAE/m), total flavonoid contents (TFC) (163.62 mg RE/mL), and proanthocyanidin contents (PAC) (728.34 mg/mL) compared to RL (control) and other treatments. Furthermore, URLH-48 demonstrated an increase in the concentrations of quinic acid (486.96 mg/L) and gallic acid (201.42 mg/L), as determined by HPLC-UV analysis. Additionally, FTIR spectral analyses demonstrated that TFUT-assisted fermented RL exhibited a greater degree of flexibility and mobility in its secondary structures compared to RL (control). The amino acid’s profile of RL was significantly increased as LAB degraded the RL proteins, and the function of TFUT facilitates bacterial activity. Moreover, SEM observation provides convincing evidence that TFUT improves and speeds up the breakdown of proteins’ structures, resulting in irregular and dense structures. Correlation and molecular docking research suggest that TFUT has different impacts on specific RL and fermented RL characteristics. The analyses conducted using GC–MS and E-nose indicated the generation of highly volatile flavor compounds through fermentation. The sensory evaluation results show an increase in liking following fermentation and TFUT-assisted fermentation, which is attributed to the production of flavor compounds. Consequently, the combined use of TFUT-assisted fermentation markedly improves the polyphenolic composition, antioxidant capacity, flavor profile, micromorphology, and overall quality of RL, which may enhance their functionality and broaden their applications in the food industry.

中文翻译：

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研究三频超声辅助发酵稻糟：对理化、结构、形态和代谢特性的影响


本研究考察了三频超声处理 （TFUT） 辅助乳酸菌 （LAB-L. plantarum 和 L. helveticus 发酵 24 h 和 48 h） 对稻酒糟 （RL） 化学、结构、形态、代谢和感官特性的影响。与 RL （对照） 和其他处理相比，瑞士乳杆菌 （URLH-48） 发酵的超声辅助 RL 总酚含量 （TPC） （112.1 mg GAE/m） 、总黄酮含量 （TFC） （163.62 mg RE/mL） 和原花青素含量 （PAC） （728.34 mg/mL） 最高。此外，通过 HPLC-UV 分析确定，URLH-48 显示奎宁酸 （486.96 mg/L） 和没食子酸 （201.42 mg/L） 的浓度增加。此外，FTIR 光谱分析表明，与 RL （对照） 相比，TFUT 辅助发酵的 RL 在其二级结构中表现出更大程度的灵活性和迁移率。随着 LAB 降解 RL 蛋白，RL 的氨基酸谱显著增加，并且 TFUT 的功能促进了细菌活性。此外，SEM 观察提供了令人信服的证据，表明 TFUT 改善并加速了蛋白质结构的分解，从而导致不规则和致密的结构。相关性和分子对接研究表明，TFUT 对特定 RL 和发酵 RL 特性的影响不同。使用 GC-MS 和 E-nose 进行的分析表明，发酵会产生高度挥发性的风味化合物。感官评价结果显示，发酵和 TFUT 辅助发酵后，人们的喜好有所增加，这归因于风味化合物的产生。 因此，TFUT 辅助发酵的联合使用显著改善了 RL 的多酚组成、抗氧化能力、风味特征、微观形态和整体质量，这可能会增强其功能并拓宽其在食品工业中的应用。