Extraction Of Tussah Silkworm Pupa Protein And Optimization Of Processing Characteristics

China is the birthplace of the world's sericulture industry,with an annual output of300,000 tons of silkworms.Silkworm pupa protein has higher nutritional value than most other animal proteins and has a complete variety of amino acids.However,due to the particularity of silkworm pupa itself,the development and utilization of pupa protein resources are restricted,so how to fully develop silkworm pupa resources plays an important role in the development of sericulture in my country.In this study,tussah pupa was used as raw material,firstly,it was degreasing and protein extraction,and then its processing characteristics were studied,and then SDS-PAGE gel electrophoresis test was performed to analyze the bands and determine the molecular weight.It is expected that tussah pupa protein will be used in food processing The application can better play its role.In addition,using an ultrasonic cell disruptor to modify the processing characteristics and structure of the protein,also called ultrasonic modification,uses the uniform design method to optimize the process conditions,and compares the processing characteristics,amino acid composition and molecular structure of the protein before and after the modification.Further expand the application range of tussah pupa protein,and maximize the economic value of tussah pupa protein.The research results are as follows:1.The solubility of tussah pupa protein is better under alkaline conditions;the solubility at higher temperature is obviously higher than that at low temperature.The longer the time the tussah pupa protein binds to water,the stronger the water holding capacity(P<0.05);the better the water holding capacity is under the temperature of 40?.The higher the p H,the better the emulsification and emulsification stability of the protein(P<0.05);when the temperature is around 55°C,the emulsification and emulsification stability are the best(P<0.05).Compared with the foaming stability,the foaming property of tussah silkworm pupa protein changes more obviously by the p H value.The foaming property of alkaline pupa protein is higher than that of acidic,and the foaming property reaches the peak value at about 10(P < 0.05);the foaming property and foaming stability reach the peak value at 35?(P <0.05).The tussah silkworm pupa protein was subjected to SDS-PAGE gel electrophoresis test,and 8 protein bands were separated and the molecular weights were 178,72,64,62,42,30,28,16 k Da.2.The tussah pupa protein was modified with an ultrasonic cell disruptor,and the solubility was used as the detection and evaluation index,and the uniform design methodwas used to design.According to the uniform design,the best process conditions for ultrasonic modification: the concentration of suspension 9 %.The ultrasonic processing time is 100 min,and the ultrasonic amplitude is 40%.At this time,the solubility of tussah pupa protein was 4.57 times higher than that before modification,and the result was significant(P<0.05).3.Prepare modified tussah silkworm pupa protein powder,and compare the processing characteristics of the protein before and after modification.The results showed that the processing characteristics of tussah silkworm pupa protein were improved after modification,and it was significant(P<0.05).The disulfide bond of the modified tussah pupa protein was broken and its content was reduced by 1.21 times(P<0.05),and the content of sulfhydryl groups was increased by 0.82 times(P<0.05).The content of essential amino acids(EAA)of tussah pupa protein after modification was increased(P<0.05)compared with EAA(13.21%)before modification,and the content reached 15.79%.After infrared spectroscopy analysis,the functional groups and secondary structure of the modified tussah pupa protein have also changed significantly.The shape and area of the protein characteristic absorption peaks in the spectrum have changed to varying degrees;in the secondary structure ?-The content of helical and random coil structures increased significantly,and the content of ?-sheet structures decreased.In summary,after ultrasonic modification,the spatial structure of the tussah pupa protein molecule changes,which improves its processing characteristics and nutritional value.