Application of Whey Protein Isolate-Soybean Oil Pre-Emulsions Stabilized by Ethanol and Rutin in Low-Fat Meatballs

The effect of fat replacement with whey protein isolate-soybean oil pre-emulsions stabilized by ethanol and rutin on the quality of low-fat meatballs was studied. By measuring the emulsion stability, texture, viscosity, particle size and rheological characteristics of pre-emulsions, the best concentration of soybean oil in pre-emulsions was selected. The fat in meatballs was replaced at proportions of 0% (control), 25%, 50%, 75% and 100%, and the best fat replacement proportion was determined by measuring the cooking loss, color difference, texture, volatile compounds, viscosity, and sensory and antioxidant properties. The results showed that the pre-emulsion with soybean oil content of 72% had the best emulsion stability, good gel morphology and the highest viscosity; when the soybean oil concentration exceeded 72%, the particle size of pre-emulsions increased and the elastic modulus decreased. Compared with the control group, the cooking loss, the ΔE value, texture, viscosity and sensory score of meatballs with 25% fat replacement had no significant changes, and the content of off-odor compounds such as nitrogen oxides, methyl compounds and sulfide did not increase. On the 9th day of storage, the thiobarbituric acid reactive substances (TBARs) value of all samples with fat replacement was significantly lower than that of the control group (P < 0.05). Therefore, whey protein isolate pre-emulsions containing 72% soybean oil was the best fat replacer, and the best replacement level was 25%.