Preparation Of Salt-enhanced Peptide By Spent Hen Protein And Its Application In Cantonese Sausage

Salt is the most common seasoning in the food industry,which plays an important role in improving the flavor and inhibiting the growth of microorganisms.However,the high dietary sodium intakes from table salt are closely related to the development of various cardiovascular diseases and cancer.In this work,the spent hen protein was hydrolyzed by papain to prepare the salt-enhanced peptides and the enzymatic hydrolysis processing was optimized.Then,the effect of calcium chloride and high pressure pretreatment on the enzymatic characteristics and the salty taste modulate activity of enzymatic hydrolysate were investigated,which could provide a theoretical basis for the application of calcium chloride and high pressure technology in the preparation of salty peptides by enzymatic hydrolysis.The optimal salt-enhanced peptide was mixed with salt substances to develop the low-sodium salt and was added to Cantonese sausage.The qualities of low-sodium Cantonese sausage were analyzed to provide theoretical support for the industrial production of low-sodium meat products.The main research results are as follows:1.The spent hen protein was hydrolyzed by papain to prepare the salt-enhanced peptides.The enzymatic hydrolysis processing was optimized by single factor experiments and orthogonal tests.Results showed that the optimal enzymatic hydrolysis was obtained at enzymatic hydrolysis time of 4 h,incubation temperature of 50°C,enzyme to substrate ratio of 2‰?w/w?,and the meat-water ratio of 1:2?w/w?.The salty taste of 50 mmol/L NaCl solution was enhanced of 26.2%by optimal protein hydrolysate.Variance analysis presented that there were significant effects?P<0.05?of hydrolysis time,enzyme concentration,the ratio of meat to water and the interaction between time and enzyme concentration on the degree of hydrolysis.The hydrolysis time had a remarkable effect?P<0.05?on the salty taste enhancing activity of hydrolysates.Principal component analysis of the taste sensor output data displayed that the differences of the flavor among 27samples were mainly related to the enzymatic hydrolysis time.2.The effects of CaCl₂?0,10,40,80 mmol/L?and high pressure?0.1,100,200,300,400 MPa?pretreatment on the proteolytic properties of spent hen protein and the salty taste modulate activity of its hydrolysate were investigated.The results showed that the protein recovery rate and the degree of hydrolysis decreased with increasing CaCl₂concentration and significantly reduced?P<0.05?when the pressure?300 MPa.The conductivity and zeta potential of the hydrolysate increased with the addition of CaCl₂,while declined with raising the pressure.Moreover,the collaborative pretreatment of CaCl₂ and high pressure could enhance the salty taste enhancing activity of the hydrolysates,which could increase the salty taste of 50 mmol/L NaCl solution by 45.2%upon 200 MPa and 80 mmol/L CaCl₂,and presenting the highest salty signal value in electronic tongue.Furthermore,the combined pretreatment of CaCl₂ and high pressure were contributed to the release of peptides with 500–1000 Da.3.The effects of the low-sodium salt on the qualities of Cantonese sausage were studied.Compared to the control sample,the low-sodium salt led to a decrease of water content,nitrite residues and the thiobarbituric acid reactive substances,but an increase in the content of protein and the volatile basic nitrogen,followed by the reduction of the total colony count,and the number of Lactobacillus,Staphylococci/Micrococci,yeasts and molds in the low-sodium Cantonese sausage.With the addition of hydrolysates,the hardness,chewiness,and the lightness value?L^*?of low-sodium Cantonese sausage were demonstrated increased.However,the yellowness value?b^*?,saltiness score and the bitterness signal values of the low-sodium sausage slightly decreased?P>0.05?.As for the sample extracted from low-sodium Cantonese sausage,the peptides with molecular weight>10000 Da significantly reduced?P<0.05?,while the small peptides with<1000Da obviously increased?P<0.05?.In addition,the amount of free amino acids especially umami amino acid such as glutamic acid and alanine in low-sodium Cantonese sausage increased.The content of sodium ions in the three groups of the low-sodium Cantonese sausages with added spent hen protein hydrolysates were reduced by 48.68%,55.92%,and68.42%respectively.