Selection Of Debittering Adjunct Culture And Flavour Enhancer For Manufacturing Low Sodium Cheddar Cheese

With the higher pursuit of dietary nutrition,functional food or food with specific dietary needs have become the focus of food research,and reducing the content of sodium in cheese has become a great challenge for dairy industry.Cheddar cheese has higher consumption and higher salt content(about 6 g/kg),which may cause hypertension and cardiovascular diseases.while low salt cheese is too viscous and has unpleasant taste residues such as acid and bitterness.Present study attempted to use debittering starter and flavour enhancer in combination with KCl instead of NaCl to reduce sodium content of Cheddar cheese to mask the off-flavours and bitterness recognized in Cheddar cheese containing potassium salts.First,degradation of a bitter peptide by lactic acid bacterial peptidase was examined.5 strains of cell-free extract(CFE)were added to bitter taste peptide solution for enzyme reaction,after the enzyme reaction was terminated using HPLC for detection.The results showed that strain M5 had the highest degradation activity of bitter peptides.5 strains of CFE were added to the cheese soluble extract,and the surface hydrophobicity of the water-soluble extract was detected by fluorescence spectrophotometer.It was concluded that the M5 CFE had the smallest hydrophobicity on the cheese surface,and it was concluded that the hydrophobic peptide was the least and the bitterness value was the lowest.Combined with these two indexes,we selected strain M5 as the debitter starter of low sodium Cheddar cheese.Then the effects of different environmental conditions on the growth of strain M5 were preliminarily investigated,so that the strain could adapt to the growth environment of low-sodium Cheddar cheese.Strain M5 grew well in acidic system with high salt(potassium salt)and low temperature(5-15?)of Cheddar cheese.Then the flavor enhancers were screened,and the bitterness and saltiness values of different combinations of flavor enhancers in the salt solution were determined using the electronic tongue.Finally,the combination of adenosine 5-phosphate(AMP)and arginine(ARG)was found to have the smallest bitterness value and the highest salty taste value.In order to optimize the amount of KCl substitution and the amount of flavour enhancers,Cheddar cheese was prepared by orthogonal test.The bitterness value and saltness value of the cheese were evaluated at 60 d of Cheddar chesse ripening.Low sodium cheese with 75% sodium chloride substitution,1 g/L arginine and 300 mg/L AMP gave best results without sensory loss.Finally,With normal salt cheese and low salt cheese as control,debittering strains M5,300 mg/L AMP,1 g/L ARG,and 1KCl/1NaCl were applied to Cheddar cheese to determine the changes of physicochemical properties,microbial growth,protein hydrolysis,angiotensin converting enzyme inhibitory activity,texture changes,and the bitterness and saltness of each group of cheeses during ripening.The results showed that Compared with normal salt cheese(1.7% NaCl),the basic components of low salt cheese(0.85% NaCl)have little change,but the water content is high,pH value is low,protein hydrolysis increases greatly,the structure is loose,the hardness is decreased,the salt taste is missing,and the bitterness is serious.The use of KCl instead of 50% NaCl had no significant effect on protein,fat and moisture content in cheese(P>0.05),the content of sodium decreased significantly(P<0.05),the content of potassium increased significantly(P<0.05),The effect on phosphorus content,pH value,protein hydrolysis,yeast and coliform growth and texture was small;In the bitterness score,KCl instead 50% NaCl was higher than normal salt cheese,which may be caused by a certain bitterness of KCl itself,but it is far lower than that of low salt group cheese(P<0.05),and the saltiness also has a certain lack.Compared with the 50% KCl cheese,adding AMP and Arginine had little effect on the basic composition of cheese,the water content and pH value increased significantly(P<0.05),saltness increased significantly(P<0.05),and bitterness decreased significantly(P<0.05).but the bitterness value is still higher than the normal salt cheese(P<0.05).After adding the adjunct culture M5 under this formula,the hydrolysis,total free amino acid content and angiotensin-converting enzyme inhibitory activity were significantly increased(P<0.05),and the ratio of hydrophobic peptide and hydrophilic peptide significantly decreased(P<0.05).There was no significant difference in saltiness(P>0.05),and bitterness was significantly reduced(P<0.05).Therefore,it is feasible to make NaCl/KCl 1:1,adding debittering adjunt cuture M5,300 mg/L AMP,and 1 g/L arginine to manufacturing low sodium Cheddar cheese.