effect of temperature on the textural, thermal and microstructural properties of wheat flour/high amylose corn starch gels

Textural, thermal and microstructural properties of single component gels and binary composite gels (bcg) of high amylose corn starch (hylon vii) mixed with wheat flour at different wheat flour/hylon vii (wf/h) ratios (95:5, 90:10 and 85:15) and temperatures (100, 121 and 135ºc) were investigated. the visual appearance showed that as hylon vii was increased in bcg, the stronger gel was achieved. textural results confirmed by increasing hylon vii, the firmness was increased, but the springiness, cohesiveness and adhesiveness were reduced. moreover, the bcg at high temperatures showed the higher level of hylon vii, the higher water solubility index would be achieved. the gelatinization enthalpy (δh) and peak gelatinization temperature (tp) increased by improving the content of amylose in bcg. hylon vii showed the lowest peak viscosity and the bcg gel containing high amount of hylon vii indicated a reduction in the paste viscosity. the differences in the microstructure of wf and hylonvii gels were also reflected the pasting properties of the gels. consequently, bcg of wf/h develops the stronger gel which can withstand at high thermal processing such as retort to improve the shelflife of the final product.