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

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 (T-G'max.) 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 G'(max) 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 84.9 kJ/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. (C) 2011 Elsevier Ltd. All rights reserved.