Quality Properties of Dried Banana Slices with Carboxymethyl Cellulose Coating Ultrasonic Pretreatments

Dried banana slices can be nutritious snacks that meet consumers' needs. However, preserving their color, texture, and antioxidant properties is challenging during convective drying. The new approach aimed to produce high-quality dried banana slices with higher antioxidant activity and lower browning. In this paper, the simultaneous application of ultrasound (at three levels: 0 W, 500 W, and 1000 W) and carboxymethyl cellulose (CMC) coating (the ratio of banana slice mass to the coating solution mass (BS:CS) at three levels: 1:2, 1:3, and 1:4) pretreatments, and their combined effects on various characteristics of the finally obtained dried banana slices were examined. The convective drying of banana slices was carried out at 80 °C and 3 m/s air velocity to achieve a consistent moisture content of roughly 10% (kg water/kg dry matter). As the power of ultrasound was increased from 0 W to 1000 W and with changing the BS:CS ratio from 1:2 to 1:4, the results demonstrated that the effective water diffusion coefficient (D_eff), water absorption capacity (WAC), and antioxidant activity (AA) of the dried banana slices were enhanced; however, their browning index (BI) decreased. Consequently, prior to convective drying, CMC coating using an ultrasonic system can be used as a practical strategy to produce fruit chips with desirable qualitative and nutritional properties.