Effect of drying temperature on drying kinetics and quality of spring groundnut (arachishypogaea l.)

Drying of groundnut

Abstract

Groundnut pods contain a higher amount of moisture at the time of harvesting, which causes fungal infestation and drying play an important role to achieve a safe moisture content. The objective of the present study was to examine the effect of drying temperature on the drying behavior and acceptability of models of drying to prophesy the drying pattern of the groundnut pods. Forced air circulation hybrid convective-cum solar dryer and sun drying method was used to dry the groundnut pods from initial moisture of 124.97±1.34% (dry basis) to a moisture content of 8.75±0.35% (dry basis). Five mathematical models were used to forecast the drying kinetics and furthermore, moisture diffusivity was determined. The different physico-chemical parameters viz., moisture content, free fatty acids, oil content, protein, ash and colour value were ascertained before and after drying of the pods. It was observed that the drying time was less for the mechanical drying method and the best-suited model for thin layer drying of groundnut pods was the logarithmic model. The higher value of R² (0.984) and lower values of SSE (0.0015) and RMSE (0.0391) was achieved in the page model for the open sun drying method. The value of effective moisture diffusivity was highest (7.1517 x 10^-10 m²/s) for a 70^oC mechanical dryer. The quality parameters like oil, protein, and free fatty acids were increased after the drying process irrespective of dying temperature and method, but the increment was more pronounced at 70^oC.

Key Words: Groundnut pods, drying kinetics, quality, and moisture diffusivity