Fortification of Yogurt with Red Dragon Fruit’s (Hylocereus Polyrhizus) Peel Powder: Effects on Comprehensive Quality Attributes and Sensory Properties

Abstract

This study was conducted to evaluate the quality features, antioxidant capabilities, microbiological and sensory aspects of yogurt fortified with 2%, 5%, and 7% red dragon (RD) peel powder. The yogurt was formulated using the classical technology adapted to laboratory conditions. The results of the physicochemical properties showed significant differences in pH (4.73–4.36), acidity (0.18–0.16 g lactic acid/100 g), and ascorbic acid (1.17-1.34 mg/100 g) among different yogurt formulations (P<0.05). In addition, RD peel powder fortification showed increasing trends in crude fiber (1.53-3.34 g/100 g), ash (5.19-5.29 g/100 g), and moisture (76.70-80.19 g/100 g) content, respectively; while the reversed trend was observed for fat (3.48-2.36 g/100 g), and crude protein (4.49-4.07 g/100 g) contents, respectively. Furthermore, gradual progression of RD peel powder in fortified yogurt manifested an improvement of the overall antioxidant activity (1.30-1.57 µmol TE/mL). The analyses of the sensory properties demonstrated that yogurt with RD peel powder in proportions of 2% received the highest hedonic score for consumer approval. Moreover, no coliform was reported in any of the control and fortified yogurts. Therefore, it could be concluded that RD peel powder can be employed as a functional food constituent in yogurt with improved quality attributes and sensory properties compared to plain yogurt.