Which acid is predominantly formed during the fermentation of milk sugar and gives curd and yogurt their sour flavor?

💡 Solution & Explanation

Lactic acid is formed during the anaerobic fermentation of lactose sugar by bacteria such as Lactobacillus, imparting a distinct sour taste to curd and yogurt. Acids like citric acid are predominantly found in citrus fruits, whereas malic acid is abundant in apples. The conversion of milk into curd also significantly enhances its vitamin B12 content.