Effect of microwave and conventional drying process on the drying kinetics and physico-chemical quality of brown shrimp (Metapenaeus dobsonii)

Abstract

The aim of this study was to compare the drying kinetics, proximate composition, instrumental texture and colour profiling of dried shrimp (Metapenaeus dobsoni) under open sun drying (30±2°C), solar with electricity backup drying (60°C) and advanced microwave (1000W/60°C) drying techniques. Initially, the drying rate was faster and inversely related to the progress of time. Upon comparison, it was observed that the drying rate was highest in the microwave drying technique compared to solar with electric backup drying and open sun drying. The protein (15.76 to 71.12%), fat (0.39% to 5.96%) and ash content (0.54 to 3.10%) showed an increase as the drying process progressed. Furthermore, the moisture content of the dried shrimp products was observed to be in the range of 9.9 to 12.5%. The water activity of dried shrimp ranged from 0.63 to 0.69. The energy value of fresh shrimp was 70.43 kcal 100 g-1, which increased to 357 kcal 100 g-1 after drying. The hardness decreased during the drying process, while during storage, it showed an increasing trend. Higher redness and lower yellowness were observed for microwave-dried shrimps compared to other drying techniques, indicating superior quality. The study indicated more efficiency for the microwave drying technique with a higher drying rate and yielded a product with superior quality characteristics in terms of colour and texture.