Physicochemical characterization of debranched waxy rice starches and their effect on the quality of low-fat ice cream mixtures

Abstract

Excessive fat intake can have adverse health effects. Thus, consumers often look for alternative, low-fat ice cream options, but decreased fat content in ice cream can affect the taste and quality. Therefore, this study investigated the functional and physiochemical properties of debranched waxy rice (DBWR) starches as a fat substitute in ice cream. We found that after debranching, the molecular weight of DBWR starch changed from 17.03 × 106 g/mol to 9.18 × 104 g/mol. Additionally, the short-chain amylose content and dextrose equivalence value increased as the debranching degree increased. Furthermore, the particle size of the ice cream mixture gradually decreased as the degree of debranching increased, stabilizing after 4 h of debranching (1.356 ± 0.364 μm); the ice cream slurry also had a high Zeta potential (over −30 mV) and improved emulsion stability. Compared to low-fat ice cream without fat substitutes, adding DBWR starches also increased the viscosity and consistency coefficient of the mixture, reduced the amount of ice and free water, increased the amount of bound water, positively affected the glass transition temperature, and improved the melting resistance of ice cream owing to the strong interactions among short-chain amylose molecules. Specifically, 2 and 4 h of debranching had the best substitution effects. The low-fat ice cream mixtures with DBWR-2 and DBWR-4 had similar sensory properties as medium-fat ice cream mixtures. This study demonstrates that DBWR starch could be a suitable fat substitute that retains the quality and consistency of low-fat ice cream.