Effect of Different Formulations and Storage on the Physicochemical, Microbiological, and Organoleptic Characteristics of Dovyalis caffra Fruit Yogurt

Abstract

This study investigated the effect of incorporating up to 15% (w/w) Dovyalis caffra fruit pulp into cow milk yogurt. Monitoring the physico-chemical, microbiological, and organoleptic properties of these formulations was performed weekly during refrigerated (4 °C) storage for 21 days. Compared to the control, formulations with added pulp recorded enhanced contents of ascorbic acid, total polyphenols, fiber, total titratable acidity (TTA), and yellowness, which is in line with increasing fruit pulp. This, however, corresponded to significantly lower contents in fat, protein, viscosity, pH, and overall sensory acceptability. Pulp incorporation had no significant effect on moisture, ash, and water-holding capacity (WHC) of formulations. Storage for up to 21 days indicated a significant increase in TTA and a corresponding decrease in pH but no significant change in WHC and viscosity of formulations. There was no detection of coliforms, yeasts, and molds in all samples throughout the storage period. This study demonstrates that Dovyalis caffra fruit has significant potential in the formulation of nutritious, desirable, and shelf-stable fruit-based yogurts. Further product optimization is, however, recommended to maximize the organoleptic quality of the formulations.