Development of probiotic yogurt from almond and cow’s milk using Lacticaseibacillus rhamnosus GR-1

Abstract

Purpose The purpose of this study is to evaluate the effect of almond milk supplementation on the growth and viability of Lacticaseibacillus rhamnosus GR-1 (LGR-1) in yogurt samples over 6 h of fermentation and 30 days of refrigerated storage. Design/methodology/approach Four yogurt treatments (T1–T4) were inoculated with the probiotic strain L. rhamnosus GR-1 and fermented for 6 h at 37°C and then placed in refrigerated storage at 4°C for 30 days. Microbial and pH analysis of each sample was conducted every 2  h throughout the fermentation period and on Days 1, 15 and 30 of cold storage to determine the viability of L. rhamnosus GR-1. Findings All samples achieved mean microbial counts of at least 108 CFU/mL during fermentation and storage. During fermentation, mean microbial counts increased for all treatments; however, differences in mean microbial counts between treatments were not significant. During storage, the mean microbial count for T4 at 15 and 30  days was significantly higher (p = 0.031) than microbial counts on Day 1. However, mean microbial counts did not differ significantly across all storage time points for treatments 1, 2 and 3 (p > 0.05). These results suggest that the addition of almond milk, in combination with cow’s milk, is suitable for propagating and preserving the viability of L. rhamnosus GR-1 in yogurt. Originality/value There is a consumer shift towards plant-based products due to health, environmental and ethical reasons. Almond milk is a popular nondairy alternative that provides enhanced nutritional value to traditionally dairy-based probiotic yogurts. L. rhamnosus GR-1 is an especially beneficial probiotic for women as it colonizes the gut and vaginal epithelium, promoting urogenital health, including preventing the recurrence of urinary tract infections and bacterial vaginosis.