BIOTRANSFORMATIONS IN PLANT-BASED PROBIOTIC BEVERAGES DURING THE FERMENTATION PROCESS

Consumer interest in functional foods is driving the development of new plant-based probiotic beverages. This study aimed to develop a plant-based beverage with soybean extract and hibiscus and evaluate the biotransformations during fermentation. The beverage was developed with 62% hibiscus tea, 32% soymilk, and 6% sucrose. Four beverages were formulated with the probiotics Lacticaseibacillus paracasei (LP), Lacticaseibacillus rhamnosus (LR), and Lacticaseibacillus casei (LC). At 37 °C and regular intervals (0, 2.5, 5, 8, 11, and 14 h) were evaluated acidity, probiotic count, total phenolic and anthocyanin content, and antioxidant activity. In parallel, a control assay (C) was carried out without adding probiotics. The probiotic L. paracasei showed more growth (9.5 log CFU/mL) when compared to L. rhamnosus (8.5 log CFU/mL) and L. casei (8.4 log CFU/mL). The initial acid content of the beverage was 0.28 g of lactic acid/L, reaching a maximum of 1.8 g of lactic acid/L in the LP. The probiotics showed different behaviors when fermenting the beverage, with changes in the content of bioactive compounds. The probiotic beverage showed a 15 to 21.5% reduction in total phenolic content over 14 h of fermentation, while C showed a 19.5%. The anthocyanin content in C was reduced from 10.8 to 4.7 mg Dp3-Sam/L (p<0.05). However, low reduction was observed throughout fermentation in the probiotic beverage. The high acidity of the beverage may have contributed to increased anthocyanin stability. The antioxidant activity quantified by the ABTS did not differ between samples (1.2 EqT/L). In the DPPH assay, the antioxidant activity of the LP decreased (p<0.05) from 1.8 to 0 mM EqT/L; however, it did not vary for the other samples. The mixture of hibiscus tea and soymilk is a suitable substrate for the growth of the evaluated probiotics, especially L. paracasei, representing a promising proposal for developing functional beverages.