Enzyme-modified canola protein could improve gelling
gelling properties of the canola protein isolate, and boost its
potential as a food ingredient, suggests a new study from Canada.
Using the transglutaminase (TG) enzyme to modify canola protein, a by-product of canola edible oil product, researchers from the University of Manitoba's Department of Food Science report that the resulting canola protein isolate (CPI) could mimic the texture of well-known foods. The research is published in the journal LWT - Food Science and Technology. Canola is major economic crop for the production of edible oil. The leftover meal, however, is mostly used in animal feed, despite containing an excellent amino acid profile. According to the data reported by Alexandra Pinterits and Susan Arntfield, enzymatic treatment of this protein-rich meal could improve the potential of CPI to be used as a food ingredient. If fine-tuning of the results is achieved, CPI could be considered an alternative gelling agent for the food industry. Gelling agents fall under the hydrocolloids umbrella - ingredients used extensively by the food industry to texturise and stabilise food products from dressings to ice cream. Though these products are sensitive to spiralling raw material costs, the demand for hydrocolloids remains impressive. Pinterits and Arntfield considered various parameters for the optimisation of CPI gelation properties by the enzymatic process, including CPI concentration, TG concentration, treatment temperature, and treatment time. They report that all but the latter parameter affected the gelling properties, with increased concentrations of both protein and TG, and by maintaining the treatment temperature close to 40 degrees Celsius. The transglutaminase enzyme was found to increase the number of cross-links amongst the proteins, thereby increasing the gel strength, as shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. In order to evaluate the resulting gels relative to commercially food protein gels, Pinterits and Arntfield used a computer simulation to calculate the concentrations of TG and CPI required to mimic the texture of well known foods such as hard and soft tofu, bologna, and egg white. The calculations showed that the rheological properties, including hardness and elasticity, of TG-modified CPI could mimic the textural qualities of all except the egg white. However, the CPI gels could not meet the textural quality - both elasticity and hardness - of egg white, said the researchers. They suggested that fine tuning the TG content could produce gels of similar hardness, but "it is, however, unlikely that the elasticity of egg white will ever be matched by a canola protein gel." "This experiment shows that TG treated CPI can mimic the texture of well known foods, such as bologna and soft tofu," wrote the researchers. "The model produced by this experiment can serve as a useful starting point for producing CPI gels of a desired texture. Fine tuning of the formulation will, however, be required," they added. Source: LWT - Food Science and Technology January 2008, Volume 41, Issue 1, Pages 128-138 "Improvement of canola protein gelation properties through enzymatic modification with transglutaminase" Authors: A. Pinterits and S.D. Arntfield