Effect Of Low Sodium Salt Substitute On The Quality Of Dry Cured Beef

By adding massive amounts of salt(sodium chloride),the reduced moisture content prolongs the shelf life of traditional dry cured meat.However,the high level of salt also causes a problem.An increased salt intake results in cardiovascular diseases like hypertension.However,with the decrease of salt,the sensory quality of the dry cured meat products will be poor.It is therefore of paramount importance to be able to reduce the salt content of the dry cured meat products while still maintaining the quality of the products.The objective of the research is to study the effects of this low sodium salt substitute and its components on the lipid and protein degradation,oxidation,texture and flavor characteristics of the products in order to study if it is possible to process high quality dry cured beef with a low sodium content.Semitendinosus was used as the sample.The results are as follows:1)Effect of low sodium salt substitute on the physico-chemical properties in dry cured beefThe effects of low sodium salt substitute and salt on moisture content,water activity(aw),relaxation time(T2),sodium content,pH and biogenic amines were investigated.The T21 and T22 in SS were longer than that in the Control.This result indicates that some immobilized water was converted to free water and evaporated,while the remaining immobilized water may have been trapped in the meat.The above results showed that the lower moisture content in SS can shorten the processing time of the dry cured beef.Moisture content and aw in different salt treatment groups decreased with the increasing of processing time.Sodium content increased,and then remained stable.The pH value increased,and then decreased.On Day 57th,the sodium content of the low sodium salt substitute group(SS)decreased by 58.00%,and the water activity decreased by 1.23%as compared with the normal salt group(NaCl,Salt,Control).The moisture content in SS was lower(P<0.05)than that in the Control and the pH was higher.In biogenic amines(BA),cadaverine and tyramine in SS were lower than that in the Control,and histamine in SS was higher.BA in SS was lower than that in the Control.2)Effect of low sodium salt substitute on lipolysis and lipid oxidation in dry cured beefThe effects of SS and the Control on neutral lipase,acid lipase and phospholipase activity,as well as TBARS values and lipoxygenase activity(LOX)activities were investigated.The LOX activity in SS group was higher than that in the Control during the processing.LOX used polyunsaturated fatty acid(PUFA)as a substrate,resulted in the lower release of PUFA.However,the differences in free fatty acids(FFAs)and phospholipase,acid lipase and neutral lipase in the Day 57th dry cured beef were insignificant.There were no significant differences in the TBARS between SS and the Control throughout the whole process,except on Day 27th.LOX in SS was higher than that in the Control from Day 15th to Day 57th.The SS increased LOX activity and promoted lipid oxidation which generated the volatile flavor3)Effect of low sodium salt substitute on proteolysis and protein oxidation in dry cured beefThe effects of SS and the Control on proteolytic index(PI),the gene expression levels and activities of cathepsin B and B+L,carbonyl and thiol values,and amino acid taste threshold were investigated.Except for Days 0 and 15,the PI values between SS and the Control were significantly different(P<0.05).The activities of cathepsin B and B+L in SS were lower than those in the Control,and the gene expression levels of cathepsins B and L in two salt treatment groups were decreased.On Days 27th and 57th,protein carbonyl values in SS were lower than that in the Control.On Days 20th and 57th,thiol groups in SS were lower than that in the Control.The SS reduced the gene expression levels and activities of cathepsins B and L,protein carbonyl and thiol groups.In addition,a study on the taste threshold of amino acids found that amino acids in SS group increased saltiness and reduced bitterness.4)Effect of low sodium salt substitute on sensory attributes in dried cured beefThe effects of SS and the Control on texture profile analysis(TPA),shear force,color,volatile flavor components and sensory attributes were investigated.There was a significant difference in the color between SS and the Control on Days 10th and 20th.Hardness in SS was higher than that in the Control on Day 10th,but lower than the Control at Day 27th.Shear force in SS was lower than that in the Control on Day 15th,and higher than the Control on Day 20th.Aldehydes were the most abundant volatile compounds in the 57-day dry cured beef.Aldehydes,esters,alcohols,aliphatic and aromatic hydrocarbons in SS was higher than that in the Control.However,there was no significant difference in shear force,TPA,color,and sensory attributes in the 57-day dry cured beef.In the sensory evaluation,the aroma and overall flavor in SS were higher than the salt group,while the other apparent and texture attributes of two salt treatment groups were not significantly different.