Differences in hempseed protein separated from AOT reverse micelles and alkaline extraction-isoelectric precipitation

In this study, Hempseed protein isolates (HPI) and concentrates (HPC) were prepared via bis(2-ethylhexyl) ester sodium salt (AOT) reverse micelle (RMS) and alkaline extraction-isoelectric precipitation (AE) processes, respectively. And their functional properties, structure and nutritional value were compared. RMS-HPI presented a greater protein content but worse protein extraction and recovery rates than AE-HPC did. SDS‒PAGE indicated that AE-HPC dissociated during the separation process, whereas RMS-HPI remained in the natural state. The RMS-HPI was mainly composed of albumin, whereas the AE-HPC was mainly composed of edestin. Moreover, the RMS significantly improved the color of the HPI. RMS-HPI has higher solubility, foaming ability, oil holding capacity, and emulsification ability, whereas AE-HPC has higher foam stability, water holding capacity, emulsification stability, and decomposition temperature. The FTIR results revealed that a fat absorption peak was observed in AE-HPC, and the number, position and intensity of the absorption peaks of RMS-HPI and AE-HPC were different, which was related to the change in secondary structure. The CD results revealed that the main secondary structures of RMS-HPI and AE-HPC were β-sheets and α-helices, respectively. The large differences in shape, number and type between the AE-HPC and RMS-HPI were observed via SEM, which may be related to their functional characteristics and structure. In addition, the RMS-HPI has advantages in terms of amino acid composition and nutritional profile. These results indicated that reverse micelles could improve the functional and nutritional properties of hemp seed protein, which is helpful for the application of hemp seed protein in food.