Effects of potato starch addition and cooling rate on rheological characteristics of flaxseed protein concentrate

Rheological characteristics of potato starch/flaxseed protein concentrate composites were investigated using a rheometer. Effects of starch/protein mass ratio (0.2–1.0) and different cooling rate (2 °C/min, 4 °C/min and 6 °C/min) on rheological behavior of composites were studied. The study showed that G’ and G’’ increased with increase of starch mass ratio in the temperature range of 40–95 °C, in both heating and cooling process. The composites exhibited similar TGinitial′ and TGMAX′, higher than those of potato starch alone at 60.3 °C. The result of frequency sweep of the composites at the end of the cooling at 25 °C exhibited an elastic behavior at all test frequency ranges (0.06283–62.83 rad/s). Study of cooling rate on rheological characteristic of composites exhibited an increase in the G’ and G’’ values with decrease of cooling rate, probably because of gel network having a stronger structure with more time for dynamic equilibration.