Effect of Different Temperatures on Drying Kinetics and Some Quality Attributes of Strawberry

Abstract

Effects of different drying temperatures (45, 55, and 65°C) on drying kinetic parameters, physical quality attributes, and contents of bioactive compounds of strawberry samples were investigated by a pilot scale cabin dryer with air circulation. The diffusion coefficient of water was determined between (Deff) 3.69-9.75 (m2/s) × 10-10, while the diffusion activation energy (Ea) was calculated as 43.42 kJ/mol. Significant changes were observed in color parameters (L*, a*, b*, C*, Hue* and ∆E*) depending on the drying temperature. It has been determined that strawberry is an important source of phenolics and contains high amounts of three anthocyanin compounds and ellagic acid. The most abundant anthocyanin compound in strawberry samples was identified as pelargonidin-3-glucoside (80.26 mg/100g DM), and followed by pelargonidin-3-rutinoside (7.72 mg/100g KM) and cyanidin-3-glucoside (5.08 mg/100g KM). On the other hand, ellagic acid content was determined as the highest in the dried strawberries (23.11-37.04 mg/100g DM) after different drying temperatures. It is concluded that moderate temperatures (<65°C) should be chosen to dry strawberry fruit for the preservation of strawberry bioactive compounds having significant contributions to human health in addition to obtain more attractive dried strawberry products.