Study On Quality Characteristics And Fresh-Keeping Technology Of Ningxiang Pork

In this experiment,we first measured the color,pH,hydraulics,muscle fat,tenderness and volatile flavor of Ningxiang pork and landrace,and studied the quality characteristics of Ningxiang pork.Then,chilled pork was dealt with three kinds of natural fresh-keeping agent such as tea polyphenols,spicy element,chitosan in laboratory.We evaluated the preservated effect of fresh by senses,total plate count(PTC),total volatile base nitrogen(TVB-N),pH,drip loss.Chilled pork treated with preservatives got good extended the shelf life and improved the product quality.It provided reference to enhance the shelf life and flavor of the chilled pork treated by natural antistaling angent.And it can provide a theoretical basis of the research results through the application of composite natural preservative.The results showed that the shearing force(tenderness)of Ningxiang pork was significantly lower than that of landrace(p <0.05),while the shearing force of Ningxiang was better than that of ordinary landrace.Fat content was significantly higher than that of landraces(p <0.05),while the pH and water content of Ningxiang pork and landrace were not significant.GC-MS method was used to analyze the volatile flavor substances of Ningxiang pork and landrace.A total of 64 volatile flavor substances were determined.There were 53 kinds of volatile flavor substances in Ningxiang pork,including 15 kinds of aldehydes,13 kinds of esters,4 kinds of ketones,4 kinds of alcohols,1 phenols,6 kinds of carboxylic acids,alkanes 7 kinds of olefins,2 kinds of furan.A total of 42 kinds of volatile substances were detected in the common type pork,including 13 kinds of aldehydes,13 kinds of esters,2 kinds of ketones,6 kinds of alcohols,0 kinds of phenols,3 kinds of carboxylic acids,2 alkanes,1 kind of olefins,1 kind of furan.Ningxiang pork esters relative content is much higher than ordinary landraces.And Ningxiang pork unique aroma characteristics of nonanoic acid,arachidic acid,myristic acid,2-undecenal,dodecanal and other substances on the Ningxiang pig taste a certain impact.Ningxiang pork is not only a wide range of flavor substances,taste the amount of material is also greater.The optimum concentrations of tea polyphenols,allicin and chitosan were as follows: the concentration of tea polyphenols was 1.0% and the concentration of allicin was 0.3%.Chitosan concentration was 2.0%.Based on the results of single factor experiment,the best formula for the effect of chilled Ningxiang pork was as follows: 1.0% tea polyphenols,0.4% allicin,2.5% chitosan The The shelf life of chilled pork treated with this compound natural preservative was significantly longer than that of the control group.This showed the obvious effect.The usage of tea polyphenols and chitosan were not more than the maximum usage of national standard.