Effect of chitosan coating on basil (Ocimum sanctum) leaves dried by microwave-assisted drying method: Analysis of color, effective moisture diffusivity, and drying kinetics.

Basil (Ocimum sanctum) leaves, commonly known as holy basil, have various health benefits due to their rich phytochemical content. However, fresh basil leaves face challenges related to their perishability and short shelf life. This study explores the use of edible coating, specifically chitosan, to extend the shelf life of basil leaves. Then basil leaves with chitosan coating were dried using microwave-assisted drying (MAD) method with variations of microwave power (136, 264, 440, and 616 W), mass of basil leaves (5, 10, and 15 g), and chitosan concentration (0, 2.5, and 5 %). The purpose of this study is to analyze the color, effective moisture diffusivity, and drying kinetics. Five mathematical models and seven error functions were used. The Avhad and Marchetti Model was identified as the most suitable model to describe the drying kinetics of basil leaves with chitosan coating. The D value increased with decreasing mass of basil leaves, decreasing chitosan concentration, and increasing microwave power. D values ranged from 0.001 to 0.002 m/s. The thickness of the basil leaves also played a role in the fluctuation of D values. The highest ΔE value was obtained by 5 % concentration of chitosan. The chitosan coating, especially at a concentration of 2.5 %, showed discoloration indicating better preservation of the original color of basil leaves. In conclusion, this study shows that chitosan coating and MAD are effective strategies to extend the shelf life of basil leaves and can provide valuable insights for future applications in leaf drying or thin layer drying processes.