Investigation of the effects of pomegranate juice addition on physicochemical, microbiological, and functional properties of set and stirred yogurts

Pomegranate juice (PJ) (at concentrations of 13% and 17%) was added to yogurt and its physicochemical and microbial properties were investigated. PJ improved several features of yogurt, bringing an increase in total phenolic contents by 4.3–6.1 and 5.3–7.3 fold in response to 13% and 17% PJ, respectively. Also, there were increases in the total anthocyanin contents of yogurt by 2650–2870 and 3470–3820 fold in response to the said juice concentrations. These increases were observed in both set and stirred yogurts, whereas IC(50) values of the yogurts decreased by 2.2–2.6 and 3.0–3.3 fold, respectively, compared to the control samples. Total acidity, syneresis, and redness value of the yogurts increased, parallel to the increase in the PJ concentration being added. Also, Streptococcus thermophilus count decreased significantly, whereas no significant effect was observed on the population count of Lactobacillus delbrueckii subsp. bulgaricus. Among PJ yogurt samples, the panelists selected the 13% PJ stirred yogurt as the best sample. PJ was observed to contain valuable bioactive compounds with functional and medicinal effects that culminate in health benefits.