The Effects Of Different Treatments On Myofibrillar Protein Properties And Structure Of Skipjack

The meat of skipjack is more sour,the smell is heavy,the taste is bad,the red meat content is high,belongs to low value tuna.At present,Bonito is mainly used in the manufacture of skipjack.However,Skipjack fish is rich in protein.However,there is no in-depth research on Skipjack protein utilization.Therefore,it is beneficial to improve the utilization of Skipjack protein.Myofibrillar protein is the main functional component of fish products.Therefore,myofibrillar protein plays a very important role in the processing and storage of meat products.Its structure and properties directly affect the formation of fish products and the quality of fish products.In the processing process,the physical and chemical processing factors will directly or indirectly affect the functional properties of myofibrillar protein and improve the functional properties of it.In this paper,the effects of different treatments on the properties and structure of skipjack myofibrillar protein were studied with ultrasonic and ultrahigh pressure treatment.To study the effect of ultrasonic and ultra-high pressure treatment on the functional properties of myofibrillar protein in skipjack.To observe the changes of fibrin solubility,emulsification,rheology and molecular weight of protein of skipjack after ultrasonic and ultra-high pressure treatment.The results showed that the solubility and emulsibility of MP of skipjack could be improved by ultrasonic treatment within a certain time range.In a short time(3,6 min),ultrasonic treatment is beneficial to improve the gel formation stage,continue to extend the ultrasonic time,but reduce the gel formation ability.In the temperature scanning process,it is obvious that ultrasonic treatment is not good for the heat forming of MP.Combined with SDS-PAGE electrophoresis,myofibrillar protein degrades after ultrasonic treatment.The results show that MP after ultrasonic treatment is beneficial to the improvement of solubility and emulsification,but it reduces the gel property of MP.The solubility of MP treated with UHV is best in 200-300 MPa,and the emulsification and emulsification stability are best in 200 MPa.The temperature scanning process showed that at the same temperature,the G of the unprocessed samples of MP was higher than the G of the processed samples.The results show that the Super high pressure treatment,like ultrasonic treatment,improves the solubility and emulsification of MP,but reduces the gel property.Secondly,the effects of ultrasonic and ultra-high pressure treatment on the physiologic structure of myofibrillar protein in skipjack were studied.The changes of myofibrillar protein turbidity,surface hydrophobicity,thiohydryl content and Fourier infrared spectrogram were studied after ultrasonic and ultra-high pressure treatment.The results showed that,with the extension of the ultrasonic time,the MP turbidity and total mercaptopuryl content would be reduced.On the other hand,the surface hydrophobic and active mercaptopylate content increased.The total sulfhydryl content of MP will be reduced by ultra-high pressure treatment.Increase surface hydrophobic and active sulfhydryl content.But MP turbidity decreases first and then rises,reaching a minimum of 200 MPa.The analysis of Fourier transform infrared spectroscopy,the extension of ultrasonic time and the increase of pressure intensity will change the molecular structure of protein,the alpha-helix content decrease and the random curl content increases.Finally,the optimization of the gel properties of myofibrillar protein of Skipjack fish by ultrasonic and ultrasonic combined with acid treatment was studied.The results showed that the gel preparation stage was obviously enhanced by ultrasonic combined with acid treatment.As the temperature increased,the G 'was slightly higher than that of the unprocessed samples,and higher than the sample group.The hardness and elasticity of the gel prepared by ultrasonic combined with acid treatment showed little difference(P > 0.05),but the cohesion and mastication increased(P < 0.05),reaching 5.364 ±0.201 and 5.478± 2.216 after 3 min separately.After the single ultrasonic treatment of MP gel hardness,elasticity,cohesion,mastication and other texture characteristics are significantly lower than the unprocessed MP samples texture characteristics,and the difference is very significant(P < 0.05).After ultrasonic combined with acid treatment,the water holding capacity of MP samples was obviously reduced.The results show that the retention of water increased with pH deviation from the protein isoelectric point.The solubility of the sample after ultrasonic treatment with acid increased obviously(P < 0.05),and there was no difference with single ultrasonic treatment.