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.

The effects of fortification of yogurt with various functional flours on survival and growth of probiotic bacteria and sensory properties of the yogurt

“…Across all these studies, the bacteria exhibited the ability to acidify and grow, reaching viable counts of at least 10 7 –10 9 CFU/mL. Importantly, there were no adverse effects on the viability of L. rhamnosus GR-1 (Williams and Hekmat, 2017; Soltani et al , 2017; Fatima and Hekmat, 2020; Burrowes and Hekmat, 2022; Muncey and Hekmat, 2021; White and Hekmat, 2018; Dunkley and Hekmat, 2019). This study confirms the viability of producing fermented probiotic yogurt as an alternative food product that can effectively provide consumers with the health advantages of probiotics.…”

“…The observed decrease in pH is consistent with other studies that analysed the pH of plant-based milk alternative probiotic yogurts. These studies reported stable pH or increased acidity during the storage period (Fatima and Hekmat, 2020; Burrowes and Hekmat, 2022).…”

“…For example, it has shown success in fermented rice pudding, probiotic yogurt fortified with cereal grains and legumes and fermented yogurt supplemented with soy beverage (Williams and Hekmat, 2017; Soltani et al , 2017; Fatima and Hekmat, 2020). Additionally, L. rhamnosus GR-1 has been found to thrive in novel functional foods such as non-dairy, legume milk-like beverages, fruit juices and vegetable juices (Burrowes and Hekmat, 2022; Muncey and Hekmat, 2021; White and Hekmat, 2018; Dunkley and Hekmat, 2019). Across all these studies, the bacteria exhibited the ability to acidify and grow, reaching viable counts of at least 10 7 –10 9 CFU/mL.…”