The physico-chemical properties of commercial canola protein isolate-guar gum gels

Abstract Biopolymer mixtures impart desirable texture to foods. Dynamic rheology was used to characterize canola protein isolate (CPI)-guar gum gels. The effects of pH, salt, guar gum and protein concentrations on the gelling ability of CPI were evaluated. Factorial and response surface optimization models were used to identify the optimum conditions (20%, w/v CPI; pH 10; 1.5%, w/v guar gum; 0.05 m NaCl) that would simultaneously maximize G′ (≥28 000 Pa) and minimize tan δ (<0.17) values of CPI-guar gum gels. Although pH > 8 is unconventional in food systems, strong and elastic CPI-guar gum gels (G′ =56 440 Pa; tan δ = 0.18) were produced at pH 10, whereas gels prepared at pH 6 were less elastic (G′ = 2726 Pa; tan δ = 0.2). Under the optimum conditions, CPI alone formed a stronger gel (G′ = 64 575 Pa; tan δ = 0.15) than CPI-guar gum mixture, suggesting that guar gum interfered with protein gelation.