Property changes and cholesterol-lowering effects in evening primrose oil-enriched and cholesterol-reduced yogurt

The present study was carried out to investigate the changes in chemical and sensory properties and the cholesterol‐lowering effect of evening primrose oil (EPO) addition to cholesterol‐reduced yogurt. The rate of cholesterol removal reached 93.5% by β‐cyclodextrin in yogurt before EPO addition. pH, viscosity and microbial counts decreased with amounts of EPO added. The thiobarbituric acid value of cholesterol‐reduced and EPO‐enriched yogurt increased proportionally to length of storage period and amount of EPO addition, and it was significantly different between the EPO‐enriched groups than in unenriched groups in all storage periods. The production of short‐chain free fatty acids (FFA) increased with longer periods of storage. From 6 days’ storage, the amounts of short‐chain FFA in 6 and 10% EPO‐enriched groups were significantly different from other groups. Most sensory scores of 2% EPO‐enriched group were not significantly different from those of the control, whereas 6 and 10% EPO addition showed an adverse effect on sensory analysis. In blood analysis, the total cholesterol increase after 8 weeks’ feeding was dramatically lowered to 39.2% in the 10% EPO‐enriched group from 57.7% in the control. In addition, the concentration of blood triglyceride increased in the control, whereas it decreased in the 10% EPO‐enriched group. The above results indicated that EPO addition resulted in a profound lowering effect in blood lipids, although it adversely affected some sensory properties.