Rheometric non-isothermal gelatinization kinetics of mung bean starch slurry: Effect of salt and sugar – Part 1

Abstract

Gelatinization of mung bean starch (MBS) was studied by oscillatory rheological measurement. The effect of sodium chloride (5% and 10% w/w), sucrose (5% and 10% w/w) and sodium chloride–sucrose blend (5%+5%) was also studied and compared during non-isothermal heating from 40 to 95°C. The addition of sodium chloride and sucrose shifted the peak gelatinization temperature (TGmax′) to higher value. The starch gelatinization kinetics was evaluated by a non-isothermal technique as function of elastic modulus (G′) and G′ vs. time (t) data up to the gelatinization peak Gmax′ value were considered for rate estimation. A 1st-order reaction kinetics described well the gelatinization process of MBS individually and sample incorporated with 10% sodium chloride and 10% sucrose. Interestingly, addition of 5% sodium chloride, 5% sucrose and a blend of sodium chloride and sucrose (5%+5%) followed 2nd-order gelatinization kinetics. The process activation energy ranged from 19.7 to 84.9kJ/mol. The work demonstrated that non-isothermal rheological measurement could be applied adequately to characterize the gelatinization process and to evaluate reaction kinetics pertaining to gelatinization.