Evaluation of the effect of essential oil addition on the quality parameters and predicted shelf life of potato yogurt.

Potato, the third most important food crop worldwide, is rich in nutrients but low in protein. By contrast, milk is rich in protein. Yogurts produced through the cofermentation of potatoes and milk is a highly nutritious food. In addition, the quality and shelf life of yogurts are hot topics in the dairy industry. The objective of this study was to explore the effect of the addition of essential oil (EO) on the shelf life and quality of potato yogurt. The antimicrobial effects of several EOs were compared, the effect of perilla leaf EO (PLEO) content on potato yogurt was discussed, and the volatile flavor components of PLEO and PLEO potato yogurt were detected. Furthermore, the effects of storage time and temperature on the pH, microbial counts, and sensory characteristics of PLEO potato yogurt were analyzed to establish a shelf life model. Results showed that PLEO had a good antimicrobial effect and was the appropriate EO. A total of 69 compounds were detected in PLEO, with limonene being the main compound. PLEO had an effect on the pH, sensory characteristics, and viable counts of potato yogurt during storage. The best PLEO addition amount was 0.04%. PLEO had a considerable influence on volatile flavor components, and the consumer acceptance of 0.04% PLEO potato yogurt was better than that of potato yogurt without PLEO in the later stage of storage. Moreover, the shelf life of potato yogurt with PLEO was 6 days longer than that of the control yogurt. PLEO also improved the content of active terpene substances in potato yogurt. The prediction models based on pH and sensory scores at 5 °C were established as A = A 0 e 0.00323 t  and A = A 0 e 0.00355 t , respectively. Comparing the accuracy factor and deviation factor of the models revealed that the sensory prediction model was more rational than the pH prediction model. Data from this study provided support to the potential industrial application and shelf life prediction of EO yogurt.