Low-sodium Salt Based On Fish Protein Polypeptide And Its Application In Cantonese Sausage

Salt is one of the most widely used additives in food processing,which plays an important role in the flavor and texture of food and has a preservative and antimicrobial effect.However,high sodium intake can easily lead to high blood pressure and cardiovascular disease.In this paper,Larimichthys crocea and Parabramis pekinensis were used as research materials,the enzymatic hydrolysis of fish protein was used to obtain the salt-enhanced pepetides.Then through the D-optimal mixed design experiment,salt-enhanced peptides were mixed with low-sodium salt to develop a polypeptide low-sodium salt with pure saltiness and nutritional and functional properties.Finally,polypeptide low-sodium salt was added into Cantonese sausage,the effect of polypeptide low-sodium salt addition on the quality characteristics of Cantonese sausage was studied.The main research contents and results of the thesis are as follows:The effects of the saltiness enhancement of peptides during the enzymatic hydrolysis of Larimichthys crocea and Parabramis pekinensis were studied.The results showed that at 1 h and 3 h of hydrolysate of trypsin from Larimichthys crocea,enzymatic hydrolysate showed the strongest salty enhancement.It indicated that Larimichthys crocea was a good raw material for the preparation of salt-enhanced peptide.And the enzymatic hydrolysate showed strong antioxidant activity.With the deepening of enzymatic hydrolysis,the content of basic amino acids was high,and more of them were blound,which could promote the enhancement of saltiness.Two kinds of enzymatic polypeptide(H-1 and H-3),sodium chloride(NaCl),potassium chloride(KCl)and calcium lactate(CaL)were mixed by the software of D-optimal mixture design,and the regression model between the proportion of each component and the saltiness of the compound salt was established.The results showed that when h-1 and h-3 were compounded with NaCl,KCl and CaL respectively,there was no interaction among the components' saltiness.When the two polypeptides worked together,there was a significant interaction between the saltiness of each component.The formulations of low-sodium salt were optimized for three groups of experiments.And there were no significant differences in sensory and electronic tongue saltiness between polypeptide low-sodium groups and the control group.The sodium content of polypeptide low-sodium salt was only 7.91%-11.43%,which was over 70% lower than that of NaCl.The changes of peptide-peptide interaction between two different polypeptides mixed in different proportions were studied.The results showed that starting from the ratio of H-1: H-3 to 1:1,with the increase of the proportion of h-3,both electrostatic repulsion and hydrophobic interaction were enhanced,particle size distributions were moving towards macromolecular direction,and peptide-peptide molecules occured a significant aggregation effect through the balance between hydrophobic interaction and electrostatic repulsion.The effect of the addition of new type of low-sodium salt on the quality characteristics of Cantonese sausage was investigated by comparing polypeptide low-sodium salt and the common salt added into Cantonese sausage.The results showed that the content of water,Aw value and the content of protein of the polypeptide samples increased,while the pH value decreased,and the microbial content was lower than that of the control group.The redness and brightness of polypeptide low-sodium sausage were higher than that of the control group,and the hardness and chewiness were slightly lower than that of the control group.There was no significant difference in sensory quality between the polypeptide low-sodium sample and the control,and the saltiness value of the electronic tongue was slightly lower than that of the control group.The analysis of the peptides extracted from Cantonese sausage showed that the antioxidant activity of the poplypeptide salt group was significantly stronger than that of the control group,and the content of free amino acids in the polypeptide low-sodium groups were significantly higher than that of the control group,especially the flavor amino acids such as Glu and Ala.At this time,the sodium reduction of the three groups of polypeptide low-sodium salt of Cantonese sausage was 74.68%,67.72% and 69.62%.In conclusion,the polypeptide low-sodium salt developed in this study has similar taste and saltiness to common salt,and will not cause adverse effects on the quality characteristics of the product while reducing the sodium content successfully,and can be used as an ideal substitute for traditional salt.