Some properties of corn starches II: Physicochemical, gelatinization, retrogradation, pasting and gel textural properties

The physicochemical, thermal, pasting and gel textural properties of corn starches from different corn varieties (African Tall, Ageti, Early Composite, Girja, Navjot, Parbhat, Partap, Pb Sathi and Vijay) were studied. Amylose content and swelling power of corn starches ranged from 16.9% to 21.3% and 13.7 to 20.7 g/g, respectively. The enthalpy of gelatinization (Delta H-gel) and percentage of retrogradation (%R) for various corn starches ranged from 11.2 to 12.7 J/g and 37.6% to 56.5%, respectively. The range for peak viscosity among different varieties was between 804 and 1252 cP. The hardness of starch gels ranged from 21.5 to 32.3 g. African Tall and Early Composite showed higher swelling power, peak, trough, breakdown, final and setback viscosity, and lower Delta H-gel and range of gelatinization. Pearson correlations among various properties of starches were observed. Gelatinization onset temperature (T-o) was negatively correlated to peak-, breakdown-, final- and setback viscosity (r = -0.809, -0.774, -0.721 and -0.686, respectively, p < 0.01) and positively correlated to pasting temperature (r = 0.657, p < 0.01). Delta H-gel was observed to be positively correlated with To, peak gelatinization temperature and (T-p) and gelatinization conclusion temperature T-c (r = 0.900, 0.902 and 0.828, respectively, p < 0.01) whereas, it was negatively correlated to peak- and breakdown- (r = -0.743 and -0.733, respectively, p < 0.01), final- and setback viscosity (r = -0.623 and -0.611, respectively, p < 0.05). Amylose was positively correlated to hardness (r = 0.511, p < 0.05) and gumminess (r = 0.792, p < 0.01) of starch gels. (c) 2006 Elsevier Ltd. All rights reserved.