Extraction Process Of The Silybum Marianum Protein,Functionality Evaluation And Bread Preparation

In this subject,in order to meet the actual needs of the enterprise,and using the silymarin meal after the silymarin extracted by the enterprise as the experimental raw materials,the extraction methods and the process optimization of silymarin protein were studied.The functionality of the extracted milk thistle protein was evaluated,and milk thistle protein bread was developed to provide necessary reference and technology surppot for the development and comprehensive utilization of milk thistle protein.The milk thistle meal protein was extracted by alkali-dissolved acid precipitation method and enzymatic ultrasonic-assisted alkali method,and the protein extraction rate was used as the inspection index.The extraction process of these two methods was optimized and contrastivly analyzed.The optimal eatraction technologies were obtained through single factor experiment and orthogonal experiment.The optimal combination of parameters for the alkaline solution and acid precipitation method was:material-to-liquid ratio 1:16,alkaline solution pH 11,extraction temperature 60?,acid precipitation pH 5.5,centrifugal speed 4000 r/min and centrifugal time 20 min.Under these conditions,the extraction rate of milk thistle meal protein was 62.88%.The optimal parameter combination of the enzymatic ultrasonic-assisted alkali method was:adding enzyme amount 2.5%+5.0%(cellulase+amylase),enzymatic hydrolysis pH of 7,enzymatic hydrolysis time 80 min,alkaline solution pH 10,ultrasonic temperature 70?,ultrasonic power 400 W,ultrasonic time 30 min,under these conditions,the extraction rate of milk thistle meal protein was 43.56%.The alkaline solution and acid precipitation method had the higher protein extraction rate,which was better than the enzymatic ultrasonic-assisted alkaline method.Based on the decolorization rate and protein yield as the inspection indicators,the activated carbon decolorization method was used to optimize the decolorization.Moreover,the purification process of milk thistle meal protein was completed.The optimal parameter combination of activated carbon decolorization method was obtained by single factor and orthogonal experiment:activated carbon addition amount 5%,decolorization time 40 min,decolorization temperature 60?,under these conditions,the decolorization rate of milk thistle meal protein was 78.45%,the protein loss was 17.37%.The purity of the milk thistle meal protein proposed after vacuum freeze-drying was 80.99%.The results of test and analyses about the molecular weight of milk thistle meal protein showed that:the molecular weight of milk thistle meal protein is mainly distributed between 15KDa and 100KDa,and there are about 6 subunit bands with obvious expression levels.The molecular weights are 18.743,42.647,51.165,58.324,72.489 and 86.445 KDa,which are low molecular weight proteins.The subunits around 18.734 KDa and 42.647 kDa have the highest content.The functional test results of milk thistle protein showed that:Compared with rice bran protein and soy protein isolate,the solubility,water retention,foaming stability,emulsification and emulsification stability of milk thistle protein were better than the other two proteins.However,the oil retention and foaming properties were significantly better than the other two proteins,this demestrated that milk thistle protein had better functionality and application value.Therefore,the milk thistle protein can be applied to develop the protein beverages,meat products and baked goods,etc.This provided the foundation for the development and application of milk thistle meal protein.In view of the good functionality and application value of milk thistle meal protein,in this dissertation,the milk thistle protein bread was developed,and its main texture and physicochemical properties were compared and analysied comparing with the control samples.The results showed that the bread with 2%silybum protein improved the properties of the dough.The specific volume,water holding capacity,elasticity and other indicators of the bread were correspondingly improved,the hardness and aging degree of the bread were improved,and the bread quality was the best.The reserch provided the valuable exploration for the application of milk thistle protein in food engineering.