Maize and teff starches modified with stearic acid as potential fat replacer in low calorie mayonnaise-type emulsions

摘要

Fat replacers have been developed to produce low-calorie foods due to the association of fat-rich diet to lifestyle diseases. Teff (an underutilized and under-researched cereal), and maize starch pastes modified with stearic acid could be used as fatreplacers because of their reduced gelling ability and higher viscosity. The effects of teff and maize starch pastes modified with stearic acid on the rheological properties, microstructure, freeze-thaw, and high temperature stability of low-calorie mayonnaise type emulsions (LCMTE) were investigated. Starch suspensions (10% w/v) containing stearic acid (1.5%) were pasted and used to prepare LCMTE with 50 and 80% oil replacement. LCMTE with modified teff and maize starches had lower yield stress and viscosity and larger oil droplets compared to LCMTE with unmodified teff and maize starches. Increasing oil replacement level (50-80%) increased the viscosity. LCMTE with maize starch had higher yield stress and viscosity and smaller oil droplets than LCMTEwith teff starch. All samples showed shear thinning behavior (n < 1). All the LCMTE were more stable to freeze-thaw cycles and high temperature storage than full fat mayonnaise. At 50% oil replacement, unmodified and modified teff and maize starch withstearic acid could produce LCMTE. When the oil content replacement was further increased to 80% only the LCMTE with modified starches were similar to the full fat. The LCMTE made with unmodified teff and maize starches (especially those with 80% oil replacement) did not flow like a mayonnaise compared to LCMTE made with stearic acid modified starches.