In- Vitro Protein Digestibility, Chemical And Functional Properties Of Protein Isolates From Raw, Defatted And Undefatted Fermented Mung Bean

Abstract

Protein isolates (PI) was extracted from the raw mung bean , defatted fermented mung bean and undefatted fermented mung bean by using alkaline extraction-isoelectric precipitation. In this study, the In-Vitro protein digestibility, chemical composition and functional properties of all PI were investigated. The result for In-Vitro protein digestibility showed that all PI have digestibility ranged from 85.22 to 95.08%.The results of the chemical composition revealed a significant difference (P<0.05) for some nutrients. Defatted fermented mung bean protein isolate (DFMPI) showed the highest crude protein (89.48%) and the lowest crude fat (0.29%) as well as carbohydrate (3.89%). Undefatted fermented mung bean protein isolate (UFMPI) showed the highest ash content (2.43%) compared to other PI. The moisture content of all PI’s ranged from 4.07 to 5.05%, while crude fibre in all PI was undetectable. Certain functional properties of all protein isolates were significantly different (p < 0.05). DFMPI exhibited the highest oil absorption capacities (3.30 ml/g) and the lowest bulk density (0.25 g/ml). The water absorption capacities for all PI ranged from 2.19 to 2.97 ml/g. The result of foam capacity and stability revealed that all PI had highest ranged from 59.62 to 70% and 19.23 to 35% respectively in acidic condition (pH 2). Meanwhile, all PI showed a higher emulsion capacity and stability in alkaline condition (pH 8) ranged from 59-68% and 47.50 to 67.50% respectively. The protein solubility of DFMPI was significantly different (p < 0.05) from that of UFMPI and raw mung bean protein isolate (RMPI).The RMPI, UFMPI and DFMPI showed decreasing in solubility at pH 4, confirming the isoelectric of mung bean protein. This study suggested that the DFMPI could be used in food formulations requiring high oil absorption capacity, foaming capacity and emulsifying capacity. The DFMPI also can be considered as potential functional food ingredients