Optimization of foaming process: drying behaviour, physicochemical, and powder properties of hot air-assisted foam-mat dried nectarine

Abstract

Abstract Nectarine powder is widely used in the industries of baking and confectionery. The production of nectarine powder can be made by several drying techniques such as spray, tray, drum, freeze, and foam mat. This study was aimed to optimize the parameters of the nectarine foaming process. Besides, hot air-assisted foam-mat drying of nectarine was carried out to evaluate the effect of different temperatures (50, 60, and 70 °C) on drying kinetics, physicochemical and powder properties of nectarine powder. Factors studied were egg albumin concentration, carboxymethyl cellulose concentration, and whipping time that varied between 10 and 30% (by weight), 0.2–0.8% (by weight), and 3–5 min, respectively. Optimum conditions were determined as 30% of egg albumin, 0.8% carboxymethyl cellulose, and a whipping time of 5 min to get maximum foam expansion, high foam stability, and minimum foam density. The drying rate and effective moisture diffusivity of nectarine foam powder increased with increasing drying temperature. Carr Index and Hauser Ratio values were in the range of 32.31–47.00 and 1.48–2.00, respectively. Foamed nectarine powder dried at 70 °C had the lowest hygroscopicity value and the highest wettability value. No significant difference was found between the powders’ porosity (p > 0.05). The powders produced at 50 °C resulted in higher total phenolic, vitamin C, and carotenoid content.