Online

Shi, Hao

Nutrition and Food Sciences

2020

M.S.

Almond milk-based products are becoming increasingly popular as milk product alternatives. In this study, a symbiotic almond yogurt containing probiotics and inulin as a prebiotic was developed using polymerized whey protein (PWP) as a gelling agent. Plant-based starter cultures YF-L02 (Lactobacillus delbrueckii subsp. bulgaricus, Stepcoccos thermophilus, Lactobacillus acidophilus, Lactobacillus paracasei and Bifidobacterium animalis) were incubated in the almond slurry. The control and fortified (Calcium Citrate and Vitamin D) almond yogurt, were analyzed for chemical compositions, pH and viscosity changes and probiotics survivability for 10-week shelf-life. There were no significant differences between the control and fortified group in the pH, viscosity and probiotic survivability for 10 weeks test period. The pH of both groups decreased while the viscosity showed slightly increased during storage. In the final week of the study, the population of L. paracasei, Bifidobacterium could maintain above 10^6cfu/g; however, almond yogurts may not be a good medium for L. acidophilus whose population decreased rapidly over the first 4 weeks. Microstructure of almond yogurt was examined by scanning electron microscopy, indicating the gel structure was improved and strengthened by 0.6% Polymerized whey protein, 0.3 % pectin and 0.05% xanthan gum. The results indicated that PWP may be a suitable gelation agent for formulating non-dairy fermented products, and meanwhile enhance the weak gel of almond yogurt. In conclusion, symbiotic almond yogurt might be able to consider as a functional food with viable probiotic population for therapeutic effects.