Changes of probiotic fermented drink obtained from soy and rice byproducts during cold storage

- Food alternative for people with lactose intolerance.
- Plant extract with potential probiotic.
- Microbiological, physicochemical and sensory stability during storage.

Plant extracts with probiotics have been gaining ground in the functional food market. The present study aimed to evaluate the physicochemical, microbiological and sensory characteristics of probiotic fermented drink made of mixed extract of soy and rice byproducts with added waxy corn starch during cold storage (5 °C for 28 days). Furthermore, the probiotic resistance under conditions similar to the digestive tract was evaluated. Slight physicochemical and colour changes were noted in the beverage during the storage period, but these changes did not affect product quality. The sample remained within acceptable microbiological parameters, and sensory scores were higher than 3.0, within the predefined quality threshold. Fermenting microorganisms presented reduced viability during the storage period. Lactobacillus acidophilus and Bifidobacterium spp. resisted the tested gastrointestinal conditions. The product showed a 28-day shelf life, but the probiotic effect lasted only14 days. Further studies should evaluate beverage supplementation with components that could improve the viability of probiotic cultures, in order to maintain their probiotic effect for a longer time. Additionally, consumer studies should be carried out in order to assess current products' acceptance by target consumers.