Monitoring of the Fermentation and Shelf-life of Probiotic Yogurt Flavored Pitaya with Cupuassu

Abstract

Yogurt is considered the most popular fermented milk and one of the most consumed among dairy products, and when added with cultures of probiotic bacteria and fruit pulps it becomes more attractive to consumers. In this context, the objective was to prepare a probiotic yogurt with pitaya flavor and cupuaçu and to monitor the fermentation time and shelf life of the product. pH and total titratable acidity (ATT) analyzes were performed to monitor the yogurt fermentation time every 30 minutes and its shelf life during 7-day intervals, totaling 42 days of storage. During the fermentation process, the pH decreased significantly until reaching pH = 4.65 and the acidity increased significantly until reaching ATT = 0.91% of lactic acid, influenced by culture concentration of probiotic bacteria, which provided a shorter fermentation time (210 minutes). Yogurt showed a loss in quality characteristics after 35 days of storage, indicating a shelf life of approximately 30 days. On the 35^th day of storage, the results of the microbiological analysis are in accordance with the limits established by the legislation while Salmonella spp. and total and thermotolerant coliforms. However, there was the presence of deteriorating microorganisms, such as the presence of molds and yeasts in disagreement with current legislation, considered thus unsuitable for consumption, confirming the expiry date of the yogurt.