Evaluation of Technical, Physicochemical and Functional Properties of Moth Bean (Vigna aconitifolia L.) Pod Coat Powder for Food and Industrial Applications

Abstract

Moth bean is an agricultural staple crop that has been used as food, fodder, and green manure, along with its by-products like stem, husk, and pod coat. These by-products are an excellent source of high nutritional value, which can be used to supplement the diet. Moth bean pod coat was dried using a Recirculating tray dryer (MRTD), a Tray dryer (MTD), and a Through flow dryer (MTFD) at 40°C (T1) and 45°C (T2) to determine the best drying method and temperature combination for the preparation of dried pod coat powder. The dried pod coats were ground to obtain powdered samples for assessment of engineering, physicochemical, and functional properties at 3, 6, and 9% moisture contents (on dry basis). The pod coat powder samples displayed significant differences in engineering properties and physicochemical properties. The sample with 3% moisture content dried at 40°C(T1) using MRTD resulted in better engineering properties and phytochemical properties like bulk density (114.6 kg/m3), tap density (128.2 kg/m3), polyphenol content (17.21 mg GAE g-1), flavonoid content (6.31 mg CAE g-1) in comparison to other powder samples. The samples of tray drying (MTD)and through-flow drying methods showed decreasing trends of nutrient retention and powder properties. The results for proximate composition were found close to each other for all drying methods, but differed slightly in the case of fibre content. The tray drying sample (MTD) has crude 17.31% fibre content compared to other dried sample. The presence of a good amount of viable minerals in the dried samples is reflected by a high ash content of 3-4% in MRTDT1 powder at 3% moisture content. Overall, the results obtained indicated that moth bean pod coat powder with a 3% moisture content dried by recirculatory dryer at 40°C showed the best results and has potential to be used as a raw material for food applications.