Impact of Different Drying Techniques on Neem Seeds Drying Kinetics and Oil Quality

Abstract

Neem oil is a promising alternative for synthetic chemicals in food preservation and an active functional agent in food packaging. Drying studies were conducted on neem seeds using different drying methods, and the oil yield profile and nutritional content such as azadirachtin content, functional groups, and elemental composition were analysed. Tray drying at 60°C showed a faster drying rate with a minimum quality of the oil. The process parameters were statistically optimized by analysing the effect of drying methods and thickness (15 and 30 mm) on azadirachtin content and oil yield. Maximum oil yield and azadirachtin content of 42.1 and 0.053% were obtained in solar drying with 15 mm bed thickness. Fourier-transform infrared spectroscopy analysis showed that there is no change in the functional group when the neem seeds were dried, and the peak absorption wavenumber confirmed the presence of O-H stretching, C-H stretching, C-O stretching, C-H bending, O-H bending, C=O stretching, and N-H stretching. Sun- and solar-dried neem seeds showed maximum retention in elemental composition when compared to the tray-drying method.