This work investigated the effects of the combined use of thermosonication-preconditioned lactic acid bacteria (LAB) with the addition of ultrasound-assisted pineapple peel extracts (UU group) on the post-acidification potential, physicochemical and functional qualities of yogurt products, aimed at achieving prolonged preservation and enhancing functional attributes. Accordingly, the physical–chemical features, adhesion properties, and sensory profiles, acidification kinetics, the contents of major organic acids, and antioxidant activities of the differentially processed yogurts during refrigeration were characterized. Following a 14-day chilled storage process, UU group exhibited acidity levels of 0.5–2 T lower than the control group and a higher lactose content of 0.07 mg/ml as well as unmodified adhesion potential, indicating that the proposed combination method efficiently inhibited post-acidification and delayed lactose metabolism without leading to significant impairment of the probiotic properties. The results of physicochemical analysis showed no significant changes in viscosity, hardness, and color of yogurt. Furthermore, the total phenolic content of UU-treated samples was 98 μg/mL, 1.78 times higher than that of the control, corresponding with the significantly lower IC50 values of DPPH and ABTS radical scavenging activities of the UU group than those of the control group. Observations by fluorescence inverted microscopy demonstrated the obvious adhesion phenomenon with no significant difference found among differentially prepared yogurts. The results of targeted metabolomics indicated the proposed combination strategy significantly modified the microbial metabolism, leading to the delayed utilization of lactose and the inhibited conversion into glucose during post-fermentation, as well as the decreased lactic acid production and a notable shift towards the formation of relatively weak acids such as succinic acid and citric acid. This study confirmed the feasibility of thermosonication-preconditioned LAB inocula, in combination with the use of natural active components from fruit processing byproducts, to alleviate post-acidification in yogurt and to enhance its antioxidant activities as well as simultaneously maintaining sensory features.

中文翻译：

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结合热超声微应力和菠萝皮提取物添加实现酸奶发酵中的质量和后酸化控制


这项工作研究了热超声预处理乳酸菌（LAB）与超声辅助菠萝皮提取物（UU组）的联合使用对酸奶产品的后酸化潜力、理化和功能品质的影响，旨在实现长期保存并增强功能属性。据此，对差别加工酸奶在冷藏过程中的物理化学特征、粘附特性、感官特征、酸化动力学、主要有机酸含量和抗氧化活性进行了表征。经过 14 天的冷藏过程后，UU 组的酸度水平比对照组低 0.5-2 T，乳糖含量更高，为 0.07 mg/ml，并且未改变粘附电位，表明所提出的组合方法有效地抑制了后处理。 -酸化和延迟乳糖代谢，而不会导致益生菌特性的显着损害。理化分析结果显示，酸奶的粘度、硬度、颜色均无明显变化。此外，UU处理样品的总酚含量为98μg/mL，是对照的1.78倍，对应于UU组的DPPH和ABTS自由基清除活性的IC50值显着低于对照组。荧光倒置显微镜观察发现，差异制备的酸奶存在明显的粘附现象，但没有发现显着差异。 靶向代谢组学的结果表明，所提出的组合策略显着改变了微生物代谢，导致乳糖的利用延迟和发酵后转化为葡萄糖的抑制，以及乳酸产量的减少和显着转向形成相对弱的酸，例如琥珀酸和柠檬酸。这项研究证实了热超声预处理实验室接种物与水果加工副产品中的天然活性成分相结合，可以减轻酸奶中的后酸化，增强其抗氧化活性，同时保持感官特征的可行性。