Application Of Plasma Protein And Heme In Prepared Pork Chops

Porcine blood is one of the main by-products in slaughtering and processing of pigs.However,problems such as decentralized slaughtering,difficulties in blood transportation,and backward processing technology have restricted the application of blood,which reduced its added value greatly.Plasma protein and heme are the main by-products extracted from porcine blood.Plasma protein is rich in globulin,and the three components ?,? and ? can improve the functional properties of myofibrillar protein,such as the emulsifiability,frothiness,gelation,hygroscopicity,etc.Therefore,plasma protein can be used as curing agent,meatbind,and fat substitutes in meat products.Heme is a kind of ironcontaining porphyrin with the biological effect of supplementing iron,and is also a good natural pigment.With the quickening pace of modern life,prepared meat products have become more and more popular with consumers,thus have a wide market prospect.However,many problems may arise during the storage and transportation process of prepared meat products,such as color variation,texture properties degradation and so on,which will reduce the edible quality and consumer acceptance.Therefore,it is urgent to formulate quality standards for prepared meat products and conduct corresponding quality improvement research.This paper studies the influence of plasma protein and heme on the quality properties of prepared pork chops during the storage process by applying plasma protein and heme extracted from porcine blood by-products to prepared pork chops and observing their color and texture property.The specific research content is as follows:1.Effect of Plasma Protein on the Texture of Prepared Pork ChopsSoy isolate protein and egg white protein are used as a comparison group to study the effects of different amounts of plasma protein(1.5-3.0%w/w)on the texture property of prepared pork chops.The results show that plasma protein can improve the texture property of prepared pork chops significantly,and the optimal dosage is 2.5%.Plasma protein can reduce the thawing loss and mill loss of prepared pork chops remarkably(P<0.05),and increase the protein gel strength significantly(P<0.05).Combined with LF-NMR analysis,it is found that 2.5%plasma protein can turn part of the free water in prepared pork chops into immobilized water and the water retention is also enhanced.Compared with 3.0%soy isolate protein,plasma protein can improve the toughness,elasticity and chewiness of pork chops effectively.The rheological results show that plasma protein can prolong the denaturation temperature of myofibrillar protein,making G' and G”higher than 2.5%group egg white protein.Upon scanning electro microscope analysis,the microstructure of prepared pork chops is more compact after adding plasma protein.Therefore,plasma protein can improve the texture property of prepared meat products,and the optimal dosage is 2.5%.2.Effect of Heme on the Color of Prepared Pork ChopsAstaxanthin and capsanthin are used as a comparison group to study the effects of different amounts of heme(0.05-0.20%w/w)on the color property of prepared pork chops.The results show that heme can improve the color property of prepared pork chops significantly,and the optimal dosage is 0.1%.When the amount of heme is 0.1%,the prepared pork chops have same color enhancement effect with that of 0.2%astaxanthin and 0.08%capsanthin,but the yellowness value is lower than group capsanthin substantially.While the smell and taste of prepared pork chops do not show any significant alteration.Through 7 freeze-thaw cycles,it was found that the brightness,redness,and yellowness of prepared pork chops changed significantly during the 7th freeze-thaw after adding heme,and the stability of color freeze-thaw is higher than that of group astaxanthin and capsanthin,and the decrease rate of redness value is lower than that of group astaxanthin and capsanthin.According to the flavor picture,the distribution of heme is closer after the 0th,3rd,and 7th freeze-thaw cycles,indicating that the flavor is less affected by freeze-thaw.Therefore,heme can be used as a new natural pigment in meat products,and the optimal dosage is 0.1%.3.The Effect of Plasma Protein and Heme on the Quality of Prepared Pork ChopsThis experiment also compare the quality changes of the prepared pork chops in the group BP(0.15%heme+2.5%plasma protein),group SPI(0.20%astaxanthin+3.0%soy isolate protein),and group EWP(0.08%capsanthin+2.5%egg white protein)during the storage period at 4 ?,-1.3? and-18?.The protein and pigment in the above experimental groups are all optimum volume selected in Chapter 1 and Chapter 2.While since the color of plasma protein is light yellow,the coloring effect will be reduced when mixed with heme,the heme is expanded to 0.15%.Studies have shown that the water retention of prepared pork chops in group BP is higher than that of group SPI and group EWP in the early storage period,and the color darkening rate is also lower than that of the other two control groups at the same storage temperature.Moreover,the pH,TBARS and TVBN values are significantly lower than those of the other two groups(P<0.05).Compared with group SPI,the prepared pork chops in group BP have higher toughness,elasticity and chewiness during storage process.And the quality of prepared pork chops declines with storage time at different storage temperatures.The shelf life of prepared pork chops is 8 days when stored at 4 ?.However,the shelf life of prepared pork chops in group BP can be extended to 30 days after storage in ice temperature,and the water retention and texture property of products in ice temperature are higher than those in the storage group at 4?,but the pH,TBARS and TVB-N values are all lower than 4? storage group.In the middle storage period,the juice loss rate of prepared pork chops in group BP is less than that of-18? storage group.Therefore,plasma protein and heme can maintain the storage quality of prepared meat products,and the product quality under ice temperature storage conditions is better than that of 4?.In summary,studies have shown that plasma protein and heme can improve the quality property of prepared meat products.On the one hand,it can solve the problems of low blood utilization,environmental pollution,and waste of resources.On the other hand,it can provide a theoretical basis for the Chinese government to formulate application standards of plasma protein and heme in meat products.