Encapsulation of probiotics in whey protein isolate and modified huauzontle's starch: An approach to avoid fermentation and stabilize polyphenol compounds in a ready-to-drink probiotic green tea

A major challenge for the development of a ready-to-drink probiotic green tea beverage (RTD-PGT) is the undesired fermentation of the product by the probiotics and loss of polyphenolic compounds during shelf-life. Thus, the aim of this work was to evaluate the stability, cell survival and sensorial acceptability of a RTD-PGT formulated with Lactobacillus rhamnosus GG microencapsulated by spray drying in a matrix of whey protein isolate and modified huauzontle's starch, after refrigerated storage. Microcapsules contained 9.02 ± 0.3 log CFU/g, and for them to be incorporated to a RTD-PGT, ascorbic acid needed to be supplemented to prevent cellular loss. After 5 weeks of storage at 4 °C, the RTD-PGT showed a decrease of merely 0.44 log CFU/mL displaying final cell counts higher than the recommended 7 log CFU/mL, and no evidence of fermentation. Furthermore, 38.52 ± 0.72% of green tea polyphenols formed an insoluble complex most likely with at least one component of the microcapsules. No significant changes on the concentration of polyphenolic compounds or their antioxidant capacity were detected, and a minor change in color was quantified. The sensory shelf-life of the RTD-PGT was of at least 23 days at a 50% of consumer's rejection. In conclusion, a multipurpose encapsulation system was developed, generating a stable RTD-PGT.