Optimization of composite fruit peel powder as a texture modifier for fat free set yoghurt: A mixture design approach

Abstract

Purpose: Fruit waste (FW) is a leading food waste type generates globally. Industrial management of such FW is a great challenge. Since those wastes are rich in nutrients, phytochemicals, and other functional compounds, they can be reused by value addition. In the present study, composite fruit peel powder was formulated and optimised from the FW collected from leading fruit processing industries in Sri Lanka. This powder was utilized as a texture modifier in fat free yoghurt to minimise the whey off. Research Method: The experiment was carried out using an optimal mixture design of response surface methodology (Design Expert, 8.0.3.1 trial version) for sixteen composite samples. The independent variables were passion fruit peel (FFPP) (60.00–70.00 g/100 g), pineapple peel (PPP) (20.00–30.00 g/100 g), and orange peel (OPP) (10.00–20.00 g/100 g) powders. The dependent variables were proximate composition (fibre, fat, and ash contents), physiochemical (colour values), and technological (bulk density, swelling capacity, oil holding capacity, water holding capacity) properties. Findings: Results of the ANOVA test showed that the model and model terms significantly affect (P≤0.05) all the parameters except bulk density and oil holding capacity. The contour plots showed that the orange peel largely contributes to the fibre, fat, ash contents and redness (a*) while passion fruit peels highly contribute to the lightness (L*) and water holding capacity. PFPP (60%), OPP (20%) and PPP (20%) were selected as optimum blend due to high fibre content, water holding capacity, and lightness along with less fat content. Originality/Value: Accordingly, it is possible to optimise some quality parameters of fruit peel powders by compositing them.