The Physicochemical, Nutritional, and Antioxidative Properties of Plant-Based Quinoa Yogurt

In previous work, a kind of pure plant-based quinoa yogurt was obtained through Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus fermentation. This study evaluated its physicochemical, nutritional, and antioxidative properties. The results showed the sensory score of quinoa yogurt was 88.33 ± 1.21 points. The contents of protein, fat, and total sugar were 3.60% ± 0.01%, 2.08% ± 0.02%, and 17.76 ± 1.17 mg/g, respectively, making it a high-protein, low-sugar, and low-fat beverage. The essential amino acid and total amino acid contents of quinoa yogurt were 5.61 ± 0.21 mg/g and 15.56 ± 0.69 mg/g (p < 0.05), respectively. A series of organic acids such as lactic acid and succinic acid were produced. Forty-one types of volatile flavor compounds were detected; among them, the content of 2-pentylfuran was the highest (55.84 ± 20.97 mg/100 g), granting the yogurt a unique bean aroma, fruit aroma, and vegetable aroma. The combined action of these flavor substances enhanced the acceptance and nutritional value of the yogurt and further influenced color, texture, and storage stability. Additionally, the total phenols and DPPH radical scavenging ability of the quinoa yogurt were significantly increased (p < 0.05), endowing the yogurt with antioxidant properties. Moreover, the simulated digestion significantly increased the total phenols and antioxidant capacity of the yogurt. These results demonstrated that quinoa yogurt is a very good health drink.