Reverse micelles extraction of hemp protein isolate: Impact of defatting processing on protein functionality, nutritional properties, and aroma profile

Authors: Ohm, Jae-Bom; FANG, BAOCHEN - North Dakota State University; GU, ZIXUAN - North Dakota State University; CHEN, BINGCAN - North Dakota State University; RAO, JIAJIA - North Dakota State University

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2022
Publication Date: 9/23/2022
Citation: Ohm, J., Fang, B., Gu, Z., Chen, B., Rao, J. 2022. Reverse micelles extraction of hemp protein isolate: Impact of defatting processing on protein functionality, nutritional properties, and aroma profile. Food Hydrocolloids. 133. Article 108158 https://doi.org/10.1016/j.foodhyd.2022.
DOI: https://doi.org/10.1016/j.foodhyd.2022.108158

Interpretive Summary: Hemp seed consists of up to 28% of crude protein and is known as a good source for high-quality plant protein because of its good essential amino acid composition and high digestibility. However, the application of hemp protein is still limited in the food industry partially because of its low functionality as compared to other plant proteins. Recently, the reverse micelles extraction technique has been increasingly popular as it is more effective to separate protein and oil from plant sources than other traditional methods. The reverse micelles extraction method has been also known to improve protein functionality. However, it remains unclear what the influence of the reverse micelles extraction technique on hemp protein functionality is. In the present study, the reverse micelles extraction system was shown to be an effective method to extract protein from hemp flour. The findings from the current study reveal an ecologically friendly approach to isolate proteins with high functional qualities. It also paves the way for the future usage of the reverse micelles extraction technique in a variety of protein extraction applications.

Technical Abstract: Hempseed protein is emerging as a food ingredient because of its potential for multiple uses in formulating commercial food products. Recently, reverse micelles (RMs) extraction technology has been utilized for protein extraction because of its convenience and low cost. The aim of the current study is to investigate the influence of the defatting process on the extraction performance, chemical composition, physicochemical properties, and aromatic profile of hemp protein isolate (HPI) extracted via RMs extraction. Our results suggest that defatting is not a necessary preliminary step for efficient extraction of protein via RMs from hemp flour. HPIs obtained from non-defatted hemp flour (ND-HF) and defatted hemp flour (D-HF) exhibited great similarities in proximate composition and protein subunits, in addition to similarities in functional properties (isoelectric point, solubility, emulsifying, foaming, and thermal stability). However, a higher percentage of ß-sheet structure and a greater surface hydrophobicity were observed in HPI obtained from ND-HF. In addition, the gel formed by HPI from ND-HF displayed a higher least gelling concentration (4% w/v) with a more yellowish color and a stronger gel strength. There were also differences in aroma profile for ND-HF vs. RMs extraction of defatted samples. HPI from ND-HF yielded a higher number and content of aromatic compounds than the counterpart. The current research implies that RMs extraction could be applied to directly extract HPI from non-defatted hemp flours without any significant impact on the functionality of the protein. Skipping the defatting step also makes this a more ecologically friendly protein extraction.