Effect of drying air temperature on drying kinetics and physicochemical characteristics of dried banana

Abstract

AbstractThis study aimed to evaluate the influence of drying air temperature on drying kinetics and the physicochemical properties of dried bananas. Banana slices were dried at 40, 60, and 80°C. Drying was terminated when the samples had a moisture of 20%. Mathematical models were fitted to the moisture ratio. A generalized model of moisture was developed, to predict the moisture of samples as a function of drying time and temperature. The effective moisture diffusivity (Deff), activation energy and the drying rate (DR) were calculated. Electrical energy consumption was measured. The moisture, water activity, reducing and total sugar content, acidity, hardness, and color of the dried bananas were evaluated. The moisture decreased during drying, obtaining a mean value of 20.132%. All mathematical models fitted well to the MR data, with a determination coefficient greater than 0.95. The Midilli model was that which best fitted. The higher temperature resulted in higher Deff (3.538 × 10−9 m2 s−1) and DR, less drying time (120 min) and electrical energy consumption (4.319 kWh), higher reducing sugar content (47.51%) and hardness (28.187 N), lower acidity (1.038%), more yellow tonality (78.04°), and higher chromaticity (18.49) of the dried bananas. The optimum temperature for drying bananas was 80°C.Practical ApplicationsBanana is a fruit widely consumed in the world. However, it is very perishable, causing great waste and financial loss. Convective drying is a simple and low‐cost method, widely used in fruit processing to produce new products and extend the shelf life of food. The dried banana is a product of good sensory acceptance and therefore drying is a good alternative for processing the banana pulp. The temperature of the drying air is one of the principal parameters of this process since it influences the drying kinetics and the physicochemical properties of the dry product. Therefore, it is important to study different drying air temperatures to determine the best drying condition for dried banana production, to optimize the dried banana process and properties.