Influence of processing parameters on the drying of spice paprika

Abstract

Paprika is utilized for its strong colour and has very little pungency. The quality of ground paprika is mainly determined by its seasoning power i.e., capsaicin content its natural colour i.e., carotenoid content, its particle size and water content. Selection of proper drying conditions is necessary for minimizing thermal stress, over-drying and maintenance of relevant compounds which determine the quality of the product. Loss of red colour is caused by autoxidation of the carotenoids. It is reported that the stability of the quality of paprika, during storage is dependent on drying conditions and the degradation rate of quality increases as the drying temperature increases. In view of the importance of this spice product standardization of processing protocol is necessary. Transport properties in terms of interphase mass and heat transfer along with the diffusion coefficient were determined for paprika from drying experiments. The analysis includes the comprehensive process including the form of the product like whole fruit or pericarp, various preprocessing steps like cutting, separating, steam blanching and drying. Drying was carried out using both a conventional pilot scale convective dryer and a laboratory dryer with the additional facility of drying under inert atmosphere. For processing under inert gas, the pre- and post-drying steps of cutting, separating and grinding the product before storage were also carried out under inert conditions The influence of these pre-processing steps on the drying behaviour was characterized by determining the transport properties. Additionally, the product was also analyzed for its red colour intensity (ASTA) value, tocopherol, carotenoids and vitamin C content, to evaluate the best possible processing protocol to obtain a good quality product.