Changes of Pork Broth Composition Contents Caused by Salt During Cooking

In order to analyze the effects of salt on the difference of component contents in pork broth,pork soup with cooking 30,60,90,120 min was used as the research object. The contents,properties,molecular weight distribution,amino acid composition,fat and fatty acid contents of protein degradation products during the cooking process of salted and unsalted pork soup were determined. The results showed that the contents crude of protein,non-protein total nitrogen,soluble protein nitrogen,salt-soluble protein,amino acid,fat and fatty acid in pork broth with salt were higher than those without salt at different cooking time. The total contents of hydrolyzed amino acids in salted broth was 5.897 mg/mL,which was consistent with the trend of crude protein content in broth. The contents of salt-soluble protein increased by about 0.6 mg/mL every 30 min of cooking,and the contents of free amino acids in salted broth was significantly(P<0.05)higher than that in unsalted broth after 90 min of cooking. According to the gel electrophoresis pattern analysis,the addition of salt reduced the macromolecular protein to small molecule protein,and the molecular weight was transferred from 135~245 kDa to 35~48 kDa. The contents of monounsaturated fatty acids in salted broth was significantly higher than that in unsalted broth,and C18:1 was the highest,reaching 3.763 mg/mL at 120 min. In a word,the addition of salt can promote the dissolving,exudation and degradation of protein in broth,increase the proportion of essential amino acids,and prevent unsaturated fatty acids from being oxidized to a certain extent,which is beneficial to absorb and utilize by human body.