Rheological properties of reduced fat ice cream mix containing octenyl succinylated pearl millet starch.

The octenyl succinyl anhydride (OSA) esterified pearl millet ( Pennisetum typhoides ) starch was evaluated as fat replacer in soft serve ice cream in comparison to other fat replacers viz. inulin, whey protein concentrate-70 and commercial starch. During temperature sweep test, the yield stress and flow behaviour index of un-pasteurized ice cream mixes increased as the temperature increased from 40 to 80 °C, while the consistency index decreased. Consistency index of aged ice cream mixes containing 2% fat replacer was higher as compared to mixes with 1% level. The aged ice cream mixes exhibited non-Newtonian behaviour as flow behaviour index values were less than one. Apparent viscosity (at 50 s-1 shear rate) of control as well as ice cream mix containing 1% OSA-esterified pearl millet starch samples was 417 and 415 mPas, respectively and did not differ significantly. The overrun of the ice cream (with 5 and 7.5% fat) containing 1 and 2% of above fat replacers ranged between 29.7 and 34.3% and was significantly lower than control (40.3%). The percent melted ice cream was also low for the ice creams containing 2% of above fat replacers at 5% fat content as compared to control. However, sensory acceptability and rheological characteristics of reduced fat ice creams containing 1.0 and 2.0% OSA-esterified pearl millet starch were at par with other fat replacers under the study. Thus, OSA-esterified pearl millet starch has potential to be used as fat replacer in reduced fat ice cream.