effect of roselle extracts on the selected quality characteristics of ice cream

In this study, different concentrations of aqueous extracts (5%, 10%, 15%, and 20% w/v) from roselle (Hibiscus sabdariffa) calyces were incorporated in formulations of soft-serve ice cream as functional additives. The roselle-flavored ice cream was evaluated for physico-chemical properties (color, viscosity, pH, total solids, total titratable acidity, meltdown rate, overrun) and descriptive sensory properties. High concentration of roselle extracts had an effect on the colour of ice cream as shown by an increase (0–1.50) in redness (+a*-values) whilst the lightness (L*-values) of the ice cream decreased (80.30–64.20). As the concentration of roselle extracts increased in the formulation, the meltdown rate of the ice cream also increased from 0.74 to 2.33 g/min whilst a gradual decrease in viscosity (238.3 to 242.3 cP) was observed compared to the control (246 cP). The overrun progressively increased (14.01–33.49%) as the concentration of roselle extracts increased. The pH and total soluble solids significantly decreased (6.8–6.3 and 35.5–25.6°Brix, respectively) at higher concentrations of roselle extracts whilst total titratable acidity increased (0.16–1.5 g of malic acid per 100 g). The results of this study suggest that the ice cream sample with 5% roselle extract has a potential as a functional ice cream since it exhibited high overrun, low meltdown, desirable viscosity, high total solids and light color intensity. This ice cream was described by sensory panel as cream white, sweet and milky with vanilla flavor. The ice cream could be acceptable as consumers are familiar with its descriptive sensory properties.