Preparation and characterisation of purple dragon fruit (Hylocereus costaricensis) yogurt

Abstract

This study aimed to develop and characterize purple dragon fruit (Hylocereus costaricensis) yogurt by evaluating its physicochemical, antioxidant, and sensory properties. Yogurt was prepared using standardized milk (3.5% fat, 11.0% solids-not-fat) with varying concentrations of dragon fruit pulp (3%, 5%, and 7%). The results showed that increasing pulp concentration significantly influenced yogurt properties. Lactic acid content increased from 0.46% in the control to 1.10% in the 7% pulp yogurt, while pH decreased from 5.21 to 4.28. Antioxidant activity improved remarkably, with %RSA values rising from 20.06% (control) to 49.63% (7% pulp). Sensory evaluation on a 9-point hedonic scale indicated enhanced color and appearance at higher pulp levels, with the highest rating (9.00) observed in 7% pulp yogurt. However, consistency slightly declined, while flavor and overall acceptability remained favorable. These findings suggest that dragon fruit pulp enhances the functional and nutritional properties of yogurt, making it a promising ingredient for value-added dairy products.