The effect of multi-frequency ultrasound-assisted (20/28/40 KHz) lactic acid bacteria (LAB- Lacticaseibacillus casei, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Lactobacillus acidophilus, and Lactobacillus helveticus) fermentation (mono and co-cultures) on the metabolic, structural, micromorphological, and sensorial properties of mulberry juice were evaluated. Results indicated that multi-frequency ultrasound-assisted fermentation significantly modified the microstructure of mulberry juice powder, resulting in more porous and rougher surfaces with irregular indentations. Total phenolic content in the best-performing sample (S10) increased to 365.36 mg GAE/mL, while total flavonoid content rose to 139.20 mg RE/mL (p < 0.05). Antioxidant activity, as measured by DPPH and FRAP assays, also showed considerable improvement, with DPPH scavenging activity increasing to 87.45 % and FRAP-value to 3.27 mM TE/mL (p < 0.05). Additionally, HPLC-UV analysis revealed that the amendment in the concentrations of cyanidin-3-rutinoside (47.47 mg/L) and peonidin-3-O-glucoside (66.86 mg/L) in the S2-based sample. E-nose analysis demonstrated intense flavor profiles in fermented samples, particularly in sample S15. Sensory evaluation also highlighted that the fruity and floral aromas in co-culture fermented samples were enhanced, notably in S10, S7, and S14. Thus, combining multifrequency ultrasonication and fermentation significantly enhances the antioxidants capacity, flavor profile, micro-morphology, and overall quality of mulberry juice.

中文翻译：

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乳酸菌 （LAB） 单培养物和共培养物的多频声波发酵协同增强桑葚汁：来自代谢、微形态学、感觉和计算方法的证据


评价多频超声辅助 （20/28/40 KHz） 乳酸菌 （LAB- 干酪乳杆菌、植物乳植杆菌、副干酪乳杆菌、嗜酸乳杆菌和瑞士乳杆菌）发酵（单一和共培养）对桑汁代谢、结构、微形态和感官特性的影响。结果表明，多频超声辅助发酵显著改变了桑汁粉的微观结构，导致表面多孔、粗糙、压痕不规则。表现最好的样品 （S10） 中的总酚含量增加到 365.36 mg GAE/mL，而总黄酮含量增加到 139.20 mg RE/mL （p < 0.05）。通过 DPPH 和 FRAP 测定测量的抗氧化活性也显示出显着改善，DPPH 清除活性增加到 87.45 %，FRAP 值增加到 3.27 mM TE/mL （p < 0.05）。此外，HPLC-UV 分析显示，基于 S2 的样品中矢车菊素-3-芸香糖苷 （47.47 mg/L） 和芍药素-3-O-葡萄糖苷 （66.86 mg/L） 浓度的修正。电子鼻分析表明发酵样品具有浓郁的风味特征，尤其是在样品 S15 中。感官评价还强调，共培养发酵样品中的果香和花香增强，尤其是在 S10 、 S7 和 S14 中。因此，结合多频超声和发酵可显著提高桑汁的抗氧化能力、风味特征、微观形态和整体品质。