Impact of Cherries, Strawberries, Bilberries, and Cornelian Cherry Addition on the Antioxidant Activity of Yogurt

Increasing awareness of the negative health effects associated with high sugar intake has led to a growing demand for reducing added sugar in food products. In this study, the antioxidant properties of commercial yogurts containing pasteurized fruits were evaluated and compared with natural yogurts freshly enriched with 3-20% thawed fruits (bilberries, cherries and strawberries). Additionally, yogurts enriched with cornelian cherry were analyzed. Antioxidant activity was assessed using the ABTS and DPPH methods, along with measurements of total polyphenol content and reducing power. The effect of fruit addition on the number of yogurt bacteria was also investigated. The results showed that the addition of fruits significantly increased the yogurts' ability to neutralize free radicals, attributed to the presence of natural antioxidants and polyphenols. The addition of fruits helped maintain the vitality of lactic acid bacteria, with bacterial counts remaining well above the minimum threshold of 107 cfu/g. The findings demonstrated that cornelian cherry has great potential as a source of polyphenols with antioxidant properties. These results confirm the high nutritional value of yogurts enriched with thawed fruit, which may serve as a valuable component of a healthy diet and a healthier alternative to sweetened yogurts commonly available in stores.