Extraction Of Bioactive Components From Grain Stillage And Study On Their Activity

With the development of society and economic, corn has become one of the important energy sources to deal with the energy crisis and deficiency. So, the yield of grain stillage—byproduct of corn processing industry, will rise greatly. If we do not treat it timely, it would decay and rot, finally lead to environmental pollution. Therefore, comprehensive utilization of grain stillage makes great sense.In our country, the yield of grain stillage is very high because of the widespread alcohol production. Generally, 10-15 tons of grain stillage would generate with the production of 1 ton of alcohol. To utilize grain stillage effectively would not only lower and pretend environmental pollution, but also bring about huge economic benefit. Take the production of alcohol from corn as an example; the integrated utilization ratio of corn abroad has reached 98%, the value created from the byproducts is twice that from main products, while in our country it has wasted too much. For instance, when we make alcohol form corn by fermentation, we can collect the byproducts through distilling and drying the exhausted liquid. Because of its high nutrition, especially the high protein content, it has been used as fodders in many countries and areas. Take zein as an example, it has many strong points, such as environment friendliness, rich resource, sustainable production, which has become a research focus.There are many processing method of grain stillage and its exhausted liquid. But most of them require strict operation, expensive equipments, but the products are easy to inactivate and have low purity. For these reasons, we research on the extraction technology of active materials from grain stillage.1. We have studied to extract protein from grain stillage through alcohol-alkali method, alkali method and acid method. We decide the best extraction condition of each method, and make a comparison among the different proteins. According to single factor experiment, we research on the main factors affecting the extraction ratio: alcohol-alkali method—pH, alcohol-alkali ratio, solid-liquid ratio and extraction time; alkali method—alkali concentration and solid-liquid ratio; alcohol method—solid-liquid ratio, temperature, sodium sulfite concentration and extraction time. Finally, we make sure the optimal extraction conditions for alcohol-alkali method: extraction time is 87.2min, solid-liquid ration is 1:42.3(g:mL), alcohol-alkali ratio is 1:2.7; the actual extraction yield is 19.57%(RSD=0.88%). We make sure the optimal extraction conditions for alkali method: the extraction time is 70min, solid-liquid ratio is 1:41.60273, alcohol-alkali ratio is 1:2.9317; the high extraction yield of protein is 17.85%.2. Through measuring serum urea nitrogen and liver glycogen and mice weight-bearing experiment, we prove the high anti-fatigue and liver-protection activity of protein extracted by the alcohol-alkali method, but the hydrolysate revealed no obvious activity. We take MTT test on zein to study the inhibition to breast cancer cells. The result shows that the inhibition to breast cancer will go strong when we increase the concentration of protein until a concentration of 100μg/mL. And the inhibition to Hela cells increase until a concentration of 200μg/mL, the highest inhibition rate is 31.98%. Observing the change of mice weight, concentration of ALT and AST in serum and liver after intragastric administration, we find that a high dose of zein has the protection to liver.3. Our work research the ultrasound extraction of zeaxanthin from grain stillage and its anti-tumor activity. Through single factor experiment, we research on the main factors affecting the extraction—solid-liquid ratio, extraction time and ultrasound power. We decide the optimal extraction conditions—extraction time is 69.85min, ultrasound power is 744W, solid-liquid ratio is 1:4.5(g:mL). In this condition, the actual yield is 132μg/g, comparing to the predictive value, 137μg/g, the relative error is 3.8%. The method is proved to be credible.The inhibition to breast cancer cells and Hela cells of zeaxanthin, extracting from grain stillage by ultrasound extraction method, has been proved by our experiment. The results indicate that the ultrasound extraction method has practical application value on the extraction of zeaxanthin.Our research focuses on the active materials of grain stillage and makes full use of the abolished resources, which is a good reflection of the sustainable development policy and makes great sense to the resource utilization and environment improvement.