Structural thermostability of commercial canola protein-hydrocolloid mixtures

Proteins in a mixed system with polysaccharides may behave differently than when used alone. The thermal transition properties (denaturation temperature, Td; enthalpy of denaturation, ΔH) of canola protein isolate (CPI)-hydrocolloid (κ-carrageenan, guar gum) mixtures were assessed using differential scanning calorimetry. Factorial and response surface models were used to examine the effects of pH, salt, protein, guar gum and κ-carrageenan concentrations on the conformational stability of CPI (Td=86 °C, ΔH=16.2 J/g). CPI-κ-carrageenan mixtures treated with sodium acetate (NaC2H3O2, 68 g/l) had the highest Td values (103.2 °C), whereas mixtures treated with sodium thiocyanate (NaSCN, 40.5 g/l) had the lowest Td (92.3 °C) values. Salts decreased ΔH values of CPI-κ-carrageenan mixtures in the order: acetate