Changes in physicochemical properties of corn starch gels by heating time and mechanical effects

In this study the effects of heating time and mixing speed on physicochemical and textural properties of corn starch gels were investigated. Different mixing speeds (15, 150 and 350 rpm) and heating times (10, 30 and 45 minutes) at a constant heating temperature (95oC) were used. Higher mixing speed and heating time resulted in more breakdowns of corn starch molecules as confirmed by intrinsic viscosity results, although the effect diminished at higher mixing speeds. The 350 rpm and 45 min samples were softer and had reduced cohesiveness, gumminess and chewiness significantly in comparison with the samples prepared at 15 rpm and 10 min. With increasing the time and speed of mixing, granules underwent a greater damage level and honeycomb-like structure of the gels became bigger in cell size and the cold paste viscosity decreased. Controlling mixing time and in particular speed is a key factor during processing of starch based food gels to have final products of consistent physical and textural properties.

کلیدواژه ها:

Starch gel ، Physicochemical properties ، Mechanical effects ، Heating time