Evaluation of physicochemical properties of foam mat dried sour cherry powder

• Almost all chemical properties were decreased by increasing level of egg white.
• Sour cherry powder had maximum solubility, total anthocyanin content and pH at 65 °C.
• pH and solubility were reduced by increasing methyl cellulose, unlike other properties.
• Browning index and drying time was decreased by increasing the temperature.
• Drying temperature significantly affected on the acidity (P < 0.05).

In this study, the effects of egg white (1, 2 and 3 g/100 g) and methylcellulose (1, 1.5 and 2 g/100 g) were investigated on the density and drainage volume of sour cherry foam. Then, foamed sour cherry juice was spread on aluminum trays (3.0 ± 0.02 mm thickness) and put in drying chamber with the air temperature of 50, 65 and 80 °C. Physicochemical properties such as solubility, total anthocyanin content (TAC), pH, browning index, acidity and drying time of foam mat dried sour cherry powder were evaluated. As the concentration of methylcellulose increased, drainage volume, foam density, TAC, browning index and drying time were reduced; however solubility and pH of the samples had an increasing trend. Almost all chemical properties (except for pH) indicated a decreasing trend with the rise in egg white levels. Furthermore, it was observed that at the drying temperature of 65 °C, sour cherry powder had the maximum solubility, TAC and pH. Browning index and drying time decreased by increasing the drying temperature. Only the effect of drying temperature on acidity was significant in a way that by the increase of drying temperature, total acidity increased.