Studies on drying characteristics of turmeric and coconut using convective microwave and combined drying methods

Abstract

Drying is an important unit operation that forms an integral part of many food newlineprocessing industries. In India, most of the post harvest losses of the agricultural newlineproducts are mainly due to the lack of efficient drying techniques. India is recognized newlineas one of the largest producers and exporters of turmeric and coconut based products newlinein the world. In both the turmeric processing and desiccated coconut production newlineprocess, drying becomes a significant process. Hence, identification of suitable drying newlinetechnique for drying of theses turmeric and coconut would help the agriculturist and newlinealso agro based industries. Microwave drying was considered as an effective drying newlinemethod for various agricultural and food product in the recent years. It has been a newlineflourishing drying technique with its advantages of reduced drying time, with less newlineenergy consumption and improved quality product compared with conventional newlinedryers. Thus, drying studies were carried out using convective, microwave and newlinecombined microwave-convective drying process. newlineTurmeric drying: A preliminary drying experiment was carried out in newlinemicrowave dryer with various geometries (whole turmeric finger, rectangular slab newlineand cylindrical slices) of the turmeric rhizome. Based on the drying characteristics newlineand quality of the dried samples, cylindrical turmeric slices were considered for the newlinedrying experiments. Convective, microwave and microwave-convective drying newlineexperiments on turmeric slices were performed using tray dryer (60o newline newlineC and 2 m/s), newlinedomestic microwave oven ( 30%, 50%, 80% and 100% power level) and modified newlinemicrowave-hot air drying system (60o newline newlineC and 2 m/s along with 30%, 50%, 80% and newline100% power level) respectively. Effect of curing and microwave power levels on newlinedrying kinetics (drying time, drying rate, and moisture diffusivity), energy analysis newline(specific energy consumption), modeling and quality parameters (color value, newlinecurcumin content, functional group analysis, texture and microstructure) of the dried newlineturmeric slices were evaluated.