The study, published in the Journal of Food Science, finds that dietary intake of sesame protein isolates lowers levels of total plasma cholesterol, and has beneficial effects lipid peroxidations, triacylglycerol, and LDL-, and HDL- cholesterol concentrations.
“Sesame protein isolate consumption can reduce cardiovascular disease by reducing LDL cholesterol, triacylglycerol, and by increasing HDL cholesterol. As sesame is an important oil seed crop in various parts of the world, sesame protein isolate can be utilized in various food formulations for its beneficial effect,” stated the researchers, led by Dr Santinath Ghosh from Calcutta University.
“Sesame protein can play an important role due to availability and favorable nutrient composition. The presence of sulphur containing amino acids is an added advantage for sesame protein,” they added.
Protein isolates
According to the authors, much current research and product development is focused on products helping to reduce or control diet-related chronic diseases such as cardiovascular disease, atherosclerosis, cancer, or liver failure.
They noted that dietary protein has been shown to affect plasma cholesterol concentration and metabolism of polyunsaturated fatty acids in the liver.
Soy proteins have been extensively studied, and shown to be an effective weight reducer, whilst being effective in reducing cholesterol when compared to dairy proteins such as casein. Soy proteins have also been shown to induce a low postprandial insulin/glucagon ratio and promote a decrease of lipid peroxide, cholesterol, and triglyceride content in blood plasma.
Sesame seeds are mainly grown for their oil; however they are also a promising source of plant proteins, containing about 20 percent protein; however this can be raised to around 50 percent once defatted. The authors noted that whole dehulled sesame seeds are popular in food items because of their low price, high nutritional quality, and versatile functional properties, however the benefits of sesame protein isolate (with at least 90 percent protein on dry weight basis) are relatively unknown.
“As far as we know, there are no investigations on the dietary effects of sesame protein isolate, on experimental hyperlipidemia … The aim of the study was to assess sesame protein isolate on plasma, erythrocyte (red blood cell) membrane, and liver lipid profile and corresponding lipid peroxidation in rats with diet-induced hyperlipidemia,” wrote Dr Ghosh and colleagues.
Cholesterol reduction
The researchers reported total cholesterol, LDL-cholesterol and triacylglycerol levels were significantly reduced by sesame protein isolate fed rats with high cholesterol diets, compared to the control casein-fed rats.
HDL-cholesterol level was also seen to increase by 41 percent through ingestion of sesame protein isolate. They authors also observed up to a 64 percent lowering of plasma lipid peroxidation, as well as up to 56 percent reductions in lipoprotein oxidation susceptibility in sesame protein isolate and isolate containing cholesterol groups.
Ghosh and co workers also reported significant lowering of red blood cell membrane lipid peroxidation (up to 68 percent lower) and liver lipid peroxidation (up to 76 percent lower), from sesame protein isolate.
Gaining importance
The authors noted that sesame protein isolate was more effective in preventing the formation of lipid peroxides when compared with casein.
“This sesame protein isolate, even in association with cholesterol, was able to protect plasma lipoproteins against oxidation,” stated Ghosh and colleagues
“Therefore, our results indicate that sesame protein isolate decreases cholesterol concentration in plasma, increases HDL-cholesterol, and also decreases plasma and erythrocyte membrane lipid peroxidation with or without cholesterol fed diet in rats,” they added.
However, they noted the detail of the mechanism by which the serum cholesterol concentration is regulated by vegetable protein isolates such as sesame, and soy, remain unclear.
Source: Journal of Food Science
Volume 75, Issue 9, pages H274–H279, doi: 10.1111/j.1750-3841.2010.01821.x
“Antihyperlipidemic Effect of Sesame (Sesamum indicumL.) Protein Isolate in Rats Fed a Normal and High Cholesterol Diet”
Authors: A. Biswas, P. Dhar, S. Ghosh