Effect of shortenings containing stearic acid on blood lipids and fat digestibilities in hamsters

Tristearin (TS), a stearic acid-rich hard fat, and soybean oil (SO) were blended in different ratios to produce four functional shortenings (blends) for use in foods. Groups of hamsters were then fed diets containing TS, SO, and the four blends for four weeks. After four weeks, serum total cholesterol (CH) levels were measured: the group fed SO had 219 +/- 19 mg/dL, and the groups fed four blends had a range of 214 +/- 14 to 222 +/- 15 mg/dL. Thus, TS in the blends exerted no hypercholesterolemic effect; it even lowered serum triglycerides (SO vs. blends). Liver CH levels were significantly lower only in the group fed the blend containing the highest level (60%) of TS. While SO was nearly completely digested (97.7%), digestibility of TS in the blends was low with a range of 10.2-26.3%, which was inversely related to the level of TS in the blend. Thus, functional shortenings produced by blending TS with edible oils may not only not raise blood CH levels, but they would be free of trans fatty acids and may be classified as reduced-calorie fats.