Effect of whey protein isolates on lipid-amylose complex structure and function in diacylglycerol oleogel cakes

In bakeries, margarines are often replaced by oleogels that contain less saturated and trans fatty acids, the latter are considered as harmful ingredients to health. However, oleogels increase starch digestibility of baked products, leading to high postprandial blood sugar. An option is to add whey proteins to reduce starch digestibility. When whey protein isolate was 1.8% (w/w) in cake batter, resistant starch increased from 42.86 to 51.24%, with the consequence of reduced starch digestibility. Reduced starch digestibility was resulted from the formation of lipid-amylose complexes, as evidenced by increases in the starch complex index (from 26.50 to 27.80%), relative crystallinity (from 34.63 to 37.85%), and enthalpy change (from 605.1 to 4311 J/g). Therefore, adding whey protein isolates is effective to adjust and design oleogel functions to address the issue of high postprandial blood sugar caused by oleogels.