CATALYTIC DEAMIDATION OF CANOLA PROTEINS

Methanol-ammonia/hexane defatted-canola meal has a protein extractibil ity of less than 60% at a pH of 12. In an effort to increase its extra ctibility a process for the partial deamidation of protein in canola m eal was developed. Meal was slurried in aqueous HCl and treated with s odium dodecyl sulphate (SDS), at various levels of temperature, pH, an d time. A two-level four-factor factorial experimental design was used to investigate initially the protein extractibility. The process thus developed increased the protein extractibility of the two-phase extra cted meal from 58.0% to 96.3%. An acceptable protein yield was obtaine d at a temperature of 90-degrees-C, SDS concentration of 0.04 mol l-1 pH 2.5, and contact time of 30 min. Under these conditions 87.2% of th e protein was dissolved. Coprecipitated SDS was removed with triethyla mine acetate in acetone. The degree of deamidation was determined to b e 38.6%, and some 7% of the protein was hydrolyzed to low molecular we ight peptides. The functional properties of the protein isolates produ ced at the optimum condition were similar to those of a commercial soy protein isolate.