Effect of Fermentation Parameters on the Anthocyanin Content, Sensory Properties, and Physicochemical Parameters of Potato Blueberry Yogurt

Fruit yogurt with a variety of nutrients and fruit flavors is becoming increasingly popular among consumers. This study was conducted to achieve the optimum fermentation process parameters in preparing potato blueberry yogurt with high nutritional value and good flavor and taste by using one factor at a time experiment and response surface methodology. The optimum fermentation process was as follows: 33% potato saccharification solution, 22% blueberry juice, 38 °C fermentation temperature, 3.7% sucrose, 14% skimmed milk powder, 4% concentration of inoculum probiotics including Bifidobacterium animalis subsp. lactis BZ11, Lactobacillus plantarum LB12, and Streptococcus thermophilus Q-1 with their inoculum ratio of 1:1:2 and 12.5 h fermentation time. Potato saccharification solution, blueberry juice, fermentation temperature, and sucrose significantly affected the sensory value and quality of yogurt. Under this fermentation process, the sensory score of yogurt was 89.78. The prepared potato blueberry yogurt was rich in anthocyanins (9.41 mg/100 g), had a potential probiotic viable count of 9.31 log CFU/mL and pleasing color, and overcame the bitterness of potatoes. Electronic tongue analysis also shows that the potato blueberry yogurt had good sensory characteristics, such as high saltiness, umami, and aftertaste-A; low sourness, bitterness, and astringency; and moderate aftertaste-B and richness. This study laid the foundation for producing potato blueberry yogurt with good sensory value and high anthocyanin content.