Drying performance of blanched and unblanched basil leaves in a forced convection solar dryer

Abstract:

The present study was conducted to investigate the effect of solar drying temperatures and blanching pre-treatment on the drying behaviour of basil (Ocimum sanctum.) leaves. Freshly harvested basil leaves were dried in a forced convection solar dryer at three temperature levels: 45 °C, 55 °C, and 65 °C. Both blanched and unblanched samples were analyzed to evaluate moisture reduction rate, drying time, that solar drying, particularly when combined with blanching, is an and final product quality. The drying rate decreased progressively over time in all treatments. Blanched leaves exhibited faster drying compared to unblanched samples, with significantly reduced drying times at all temperatures. At 65 °C, blanched samples dried within 150 minutes, while unblanched samples required 240 minutes. The initial moisture content of the leaves (426–451% d.b.) was reduced to below 6% d.b. at all temperatures. Moreover, blanched samples retained better color, texture, and appearance than unblanched ones. These findings suggest effective method for improving drying efficiency and product quality in basil leaves.