Stability of polyphenols from blueberry (Vaccinium corymbosum L.) in fermented dairy beverage

The present study evaluated the influence of refrigerated storage (1, 14, and 28 days at 4°C) and blueberry juice content (0%, 5%, 10%, and 15% v/v; CON, T5, T10, T15, respectively) on physicochemical parameters of fermented milk beverage. Total phenolic and anthocyanin contents values exhibited a concentration‐dependent effect (p < .05). Blueberry juice content and refrigerated storage decreased (p < .05) pH values. Furthermore, blueberry juice decreased (p < .05) lightness (L*) and yellowness (b*), and increased (p < .05) redness (a*) values of the samples. While refrigerated storage did not affect (p > .05) phenolic content, it decreased (p < .05) the anthocyanins content values. Moreover, refrigerated storage did not affect (p > .05) titratable acidity and moisture whereas, it increased (p < .05) the total soluble solids content. These results indicated that phenolic content exhibited greater storage‐stability at 4°C than anthocyanins counterparts in fermented milk beverages. PRACTICAL APPLICATIONS: Cheese whey, initially considered as a manufacturing waste, is being increasingly demanded by the food industry because of its nutritional, technological, and sensory traits. Moreover, fruits such as blueberry are known as sources of health promoting phytochemicals including anthocyanins however, recent report documented the negative impacts of processing, temperature, and storage on such molecules. The present study evaluated the influence of blueberry juice concentration and refrigerated storage on the phytochemicals contents in a blueberry juice‐added fermented milk beverage during 28‐days storage at 4°C. Our data indicates that phenolic contents from blueberry are storage‐labile in this type of foodstuff, and the addition of blueberry homogenate at 10% (v/v) is potentially close to the optimum addition level due to the lowest relative decrease of its initial total anthocyanins content.