Investigation of total protein and casein contents of fruit yogurts by electrophoretic method

Abstract

Fruit yogurt is consumed fondly as a healthy snack. The combination of both fruit and yogurt brings together the benefits of both ingredients. Proteins are essential for a healthy life. There is limited data on the protein content of fruit yogurts. This study described the total protein and casein fraction in different fruit yogurts, mostly produced and consumed: strawberry, forest fruit, fig-walnut, mango, blueberry, peach, raspberry, and pineapple. We also provided detailed information about fruit yogurts. We employed a nanodrop spectrophotometer to determine total protein content and SDS-PAGE, a widely recognized and effective protein identification method, though it has not yet been applied to fruit yogurt. Statistical evaluation was performed with an analysis of variance. The highest total protein amount was observed in pineapple (3.51 mg/mL) and fig-walnut yogurts (3.25 mg/mL), and the lowest in forest fruit (1.21 mg/mL) and strawberry yogurts (1.27 mg/mL). The highest casein density was determined in pineapple (41.05%) and figwalnut yogurts (36.56%) and the lowest in mango (12.94%) yogurts. The remaining fruit yogurts had OD (Optical Density) values of 27.61% for strawberry, 22.40% for peach, 19.85% for raspberry, and 19.04% for blueberry, respectively. In addition, the casein of the fruit yogurts was determined around 25 kDa. The statistical differences were significant between fruit yogurts (P<0.001). As a result, yogurt producers must carefully consider their choice of starter culture to optimize both sensory attributes and health benefits, ensuring that consumers receive a product that aligns with their expectations for quality and nourishment.