Protective Effect of Sweet Potato Peel against Oxidative Stress in Hyperlipidemic Albino Rats

Abstract

In the present investigation, the valorization of sweet potato ( Ipomoea batatas L.) wastes into food application with health benefits was studied. Growing interest in the replacement of synthetic food antioxidants by natural ones has fostered research on vegetable sources and screening of raw materials to identify new antioxidants. Different parts of sweet potato contain various phenolic activities. The sweet potato peel had the highest antioxidant activity as compared to other parts. It was reported that sweet potato contains bioactive compounds such as Flavonoids, Polyphenols, The present study was executed to examine the antioxidant components of sweet potato peel and their addition to fermented cow’s milk to improve lipid profile in rats fed high fat diet. Fermented milk was prepared from cow’s milk fortified with 1% and 2% of sweet potato peels (SPP), before inoculation with starter culture containing ( S. thermophilus TH4, L. acidophilus La5 and L. bulgaricus ). It was found that addition of SPP had no significant effects on the sensory attributes (appearance, body, texture, and flavor) as compared to the control samples. Increasing the percentage of SPP resulted in a decrease in the viscosity of the fermented milk. When SPP powder was included in the diet and fed to rats, there was a significant decrease in the activities of serum transaminases (ALT and AST). Results also showed that the fermented milk administration to hyperlipidemic/hyper-cholesterolemic rats induced a significant decrease in the total cholesterol, LDL, protein and triglycerides, and a significant increase in HDL concentration. Histopathological examination showed that groups fed with SPP blended fermented milk showed less pathological changes compared to the positive control group. The main results indicated that there is a high potential for sweet potato peel extract to be utilized as antioxidant in food systems due to its high phenolic contents. It can be concluded that the antioxidant components in purple sweet potato peel when administered with fermented cow’s milk can improve serum lipid status in rats fed high fat diet.