Protein Content, Essential Amino Acid Profile and Functional Properties of Mucuna pruriens Seed Flour as Affected by Bio-Thermal Processes

Abstract

Mucuna pruriens seed is a poorly utilized legume but contains appreciable amount of protein/ amino          acids that get altered during thermal processing to make it wholesome necessitating the combination of bioprocess and thermal processes. The study was carried out to evaluate protein content, amino acid        profile and functional properties of Mucuna pruriens seed as affected by combined bioprocess and thermal processes. Soaking, boiling (1:5 w/v, distilled water,), roasting (150°C), germination (dark) and fermentation (Rhizopus oligosporus 0.4g/kg seed) was carried out. The treatments were combined: 72 h soaked + 60 min cooked, 48 h germinated + 60 min cooked, 48 h germinated + 15 min roasted and 72 h fermented + 15 min roasted. After the combined treatments, the seeds were dried (70°C) to constant weight, grinded and stored in high-density polyethylene bags. The protein content, amino acid profile and functional properties were evaluated. Crude protein content was significantly (p<0.05) increased by all the treatments with maximum increase of up to 30.40%. Leucine increased significantly (p<0.05) from 8.87 to 10.05 g/100g protein using 72 h soaking+60 min cooking, followed by tryptophan from 1.05 to 6.71 g/100g using 72 h fermentation+15 min roasting and histidine from 3.51 to 4.60 g/100g using 48 h germination+60 min cooking. Methionine was increased but the increase was not significant. Water absorption capacity, and foam capacity were significantly increased (p<0.05) while bulk density, and viscosity got reduced. This research indicates that the combination of bioprocess and thermal processes could be used to improve the protein content as well as leucine, tryptophan and histidine of Mucuna pruriens seed flour. The relative high water absorption capacity will encourage proper hydration of the flour in batter. This is crucial for dough development in baked products. While the high foam capacity suggests suitability for use in cakes and pastries.