Enzymes to extend pea protein potential: study

Treating pea protein isolate (PPI) the microbial transglutaminase (MTGase) enzyme for produced gels of "similar strength and elasticity as commercial soy protein isolate gels and commercial meat bologna," wrote the authors in the journal Food Chemistry .

This is not the first report on using TGase to modify the functional properties of proteins.

Indeed, previous studies have looked at the effect of this enzyme on casein, soy proteins, whey proteins, myosin, and globulin.

It is however a first with respect to pea protein, said the authors from the University of Saskatchewan and Agriculture and Agri-Food Canada.

"Enhancement of shear strain or gel elasticity of heat-induced PPI gels with MTGase has not been reported before and provides opportunities for extending the properties of pea proteins when developing new food products," wrote lead author Phyllis Shand.

Pea protein is classed as an alternative protein, a market that is growing at a rapid pace, for a variety of reasons.

Alternative sources of protein are having a profound influence on the formulation of weight conscious food and diets based on low glycaemic index (GI) and high protein intake.

Traditional manufacturers are beginning to take a look at new protein sources as a means of enriching their products.

The new study applied the MTGase (Activa TG-TI, Ajinomoto) treatment to pea protein isolate (PPIc, Propulse, Nutra-Pea) and native pea protein (PPIn).

Shand and co-workers report that the strength and elasticity of the resulting PPIc gels were increased as a result of MTGase treatment, and were similar to SPIc gels and commercial meat bologna.

"The enhancement of the shear stress and strain of PPIc gels by low temperature incubation with MTGase show the practical significance of the enzyme-assisted cross-linking of legume proteins, despite the relatively long incubation time needed," wrote the researchers.

"Adjustment of processing conditions, including use of MTGase, provides new opportunities to extend the range of functional properties of commercial pea proteins in food systems which have not been exploited before."

Currently there is only a limited selection of cross-linking enzymes on the market, with microbial transglutaminase (MTG) being the most widely used enzyme for modifying the structure of food.

Source: Food Chemistry (Elsevier) Volume 107, Issue 2, Pages 692-699 "Transglutaminase treatment of pea proteins: Effect on physicochemical and rheological properties of heat-induced protein gels" Authors: P.J. Shand, H. Ya, Z. Pietrasik and P.K.J.P.D. Wanasundara