Impact of ultrasonication/shear emulsifying/microwave-assisted enzymatic extraction on rheological, structural, and functional properties of Akebia trifoliata (Thunb.) Koidz. seed protein isolates

Abstract

The effects of enzymatic hydrolysis and physical pretreatments (i.e., ultrasonication, shear emulsifying, or microwave) on the yields, rheological, structural, physicochemical, and functional properties of Akebia trifoliata (Thunb.) Koidz. seed protein isolates were investigated. After cellulase-assisted hydrolysis, non-significant (P > 0.05) differences in zeta potential and amino acid composition were observed. However, higher yields (19.38%), higher protein content (52.78%) as well as improved functional properties such as water holding capacity (3.8 g/g), foaming and emulsion properties were observed, which were associated with lower particle size, higher hydrophobicity, disulfide bonds content, and thermal stability. Ultrasonication and microwave pretreatments further increased the oil holding capacity and emulsion properties of protein isolates. Shear emulsifying-assisted extraction resulted in the lowest oil holding capacity and emulsion stability, although it contained the highest emulsion capacity (104.37 m2/g) and disulfide bonds content (9.82 μM/g). A fuzzy statistical evaluation indicated that microwave assisted enzymatic hydrolysis was the most efficient improvement in the overall properties of protein isolates with the highest synthetic value (0.71). These results provided valuable information regarding the potential use of A. trifoliata seed as a new food ingredient and for extraction of protein from A. trifoliata (Thunb.) Koidz.