Modification of the physical properties of soy protein isolate by acetylation

Abstract

The predictions of previously developed models for the hydration, gelation, and solubility of soy protein isolate regarding the effect of a chemical modification (acetylation) of the protein have been borne out by experiment. Acetylation decreased water binding, increased solubility in the pH 4.5-7 range, and decreased gel strength of soy protein isolate. A shift in molecular weight distribution of the protein to lower molecular weight species also occurred. This work shows that the functional properties (in a food use context) of soy proteins can be altered by chemical modification and that the effect of a particular chemical modification of these properties can be predicted.

Modification of plant proteins by immobilized proteases

“…Mammalian kidneys contain an epsilon-lysine acylase that is capable of hydrolyzing N-formyl and acetyllysines. 257 Sui and Thompson 267 reported that succinylated whey concentrate with 37% succinylation was still a good quality protein with the net protein ratio higher than that of casein. However, they recommend metabolic and toxicity studies of the succinylated amino acids.…”

“…251 -261 Loss of charged groups of amino residues resulted in the binding of a smaller number of water molecules per protein molecule. 257 The ionic attraction between neighboring molecules that were responsible in part for stabilizing the protein gel was also reduced. 259 However, Beuchat, 256 Barber and Warthesen, 264 as well as Kabirullah and Wills 263 demonstrated that unfolding of the protein structure and dissociation of the protein into subunits enhances the entrapment of liquid resulting from the increase in interactive properties of the altered protein structure.…”

Acetylation of amino groups and its effect on the structure of soybean glycinin.

“…Soybean proteins have been modified by various chemical reactions including carboxymethylation,2) deamination,3) succinylation4) and acetylation. 4,5) These modified proteins were also tested for some functional properties Gel filtration. Protein solutions (1 ml, 2 %) were applied on a column of Litex 10 (Litex Co ., the mole cular range, 10,000-300,000) and eluted with the stand ard buffer (µ=0.3) in 3ml fractions , which were moni tered at 280nm.…”

The characteristics of selected physico-chemical properties of chemically modified myofibrillar protein

“…Chemical modifications significantly reduced the water-holding capacity of samples. Accordcing to Barman et al [2], this was due to elimination of lysine eamino group charge. Kijowski [11] reported a lower value of water-holding capacity at the level of 7 g/g protein.…”