The optimisation of processing and storage conditions of lyophilised purslane-fortified yoghurts by central composite design

Abstract

The objectives of this study were to manufacture lyophilised purslane-fortified yoghurts in order to improve the functional properties of yoghurt and to optimise processing and storage conditions of fortified yoghurts. A central composite design was created by considering the storage time (5–12 days), lyophilised purslane concentration (0.25–0.5%) and starter culture ratio (1–3%) as factors. The fortified yoghurts were supplemented by phenolics (up to 36.94 mg gallic acid equivalent per kg) and linoleic acid (3.15–11.31%). The optimal fortified yoghurt processing and storage parameters were determined to be 0.55% lyophilised purslane, 3.41% starter culture ratios and 5 days of storage at 4°C.