Impact of fruit and vegetable enrichment on functional profile and sensory acceptance of yogurts

Introduction: Fruit- and vegetable-enriched dairy products may enhance the nutritional and functional value of fermented foods. The objective of this study was to develop and characterize fermented yogurts enriched with fruit–vegetable combinations by evaluating their antioxidant capacity, probiotic potential and sensory acceptance compared with conventional yogurt.

Methods: Plain yogurt was prepared from whole milk supplemented with milk powder, gelatin and 3% commercial plain yogurt as the starter culture, then fermented at 37 °C for 8 h. Fruits and vegetables were washed, peeled when required, steam-cooked for up to 15 min, homogenized into purees and incorporated after fermentation. Four formulations were produced: a control yogurt (CT) and three enriched yogurts containing 15% fruit puree and 5% vegetable puree: blueberry–tomato (BT), apple–eggplant (AE) and strawberry–beetroot (SB), without added sugar. Total antioxidant capacity (TAC) was determined by ORAC (Oxygen Radical Absorbance Capacity) and TEAC (Trolox Equivalent Antioxidant Capacity), and total polyphenol content (TPC) by the Folin–Ciocalteu method in extractable and non-extractable fractions after 1, 7 and 14 days of refrigerated storage. Lactic acid bacteria (LAB) viability and sensory acceptance were evaluated using a five-point hedonic scale.

Results and Discussion: Fruit and vegetable enrichment influenced antioxidant capacity. BT showed the highest TPC, AE the highest ORAC values and SB the highest TEAC values. The non-extractable fraction accounted for 55–96% of TAC. LAB populations remained above 10⁸ CFU/g throughout storage, indicating stable probiotic potential. Sensory evaluation showed significant differences in overall acceptability, with CT and AE receiving the highest ratings.

Conclusions: Fruit and vegetable incorporation enhanced yogurt antioxidant properties without compromising probiotic stability. Although enriched formulations showed slightly lower sensory acceptance than the control, none were negatively perceived by consumers. These findings support the development of fermented dairy products with enhanced functional value and potential health benefits.