Influence Of Partial Substitution Of NaCl By KCl On Fat Oxidation And The Formation Of Flavor Compounds In Dry-cured Ham

Dry-cured ham is a typical traditional meat product with high sodium chloride content in China,which is favored by consumers because of its unique flavor.NaCl is an essential curing agent in the manufacture of cured meat products.However,too much sodium can cause high blood pressure and heart disease in human beings(>11%).With the development of economy,consumers tend to choose low-salt hams.Therefore,many researches have been done to study the substitution of NaCl salt at home and abroad in recent years.There is no report about the influence of partial substitution of NaCl by KCl in lipid oxidation and flavor changes in Chinese dry-cured hams during processing.This paper proposes to study related data so that we can apply to ham industry,the idiographic contents are as follows:1.Influence of partial substitution of NaCl by 40%KCl on lipid hydrolysis and oxidation.Choose green pigs as raw material.Hams were either salted with formulation I:Control,100%NaCl or formulation ?:60%NaCl,40%KCl.Semimembranosus muscle and Biceps femoris muscle were sampled randomly from green ham,end of salting,30 days of drying-ripening,60 days of drying-ripening,100 days of drying-ripening.To study the impact of KCl on lipid hydrolysis and oxidation,POV?TBARS?lipid composition and free fatty acid values were studied.The resutls showed that:POV and TBARS were significantly enhanced by KC1 in Semimembranosus(P<0.05).The maximum POV values difference between the two groups were 0.138 g/100g(control group),0.153 g/100g(substitution group)on 30 days of drying-ripening.But no significant POV difference was found in final product.Potassium substitution group significantly increased TBARS value(0.19 mg MDA/kg>0.11 mgMDA/kg)(P<0.05).KCl has no significant influence on hydrolysis of lipid,except significantly promoted phospholipids(P<0.05).Unsaturated fatty acids content in Semimembranosus was significantly enhanced by KCl(P<0.05),such as oleic acid,linoleic acid and linolenic acid.Lipid oxidation was significantly promoted by KCl in Biceps femoris.The POV values of the two groups were 0.128 g/100g(control group),0.137g/100g(substitution group)on 30 days of drying-ripening.TBARS in substitution group were higher than non-alternative groups during the whole processing.No significant influence was found on SFA,MUFA and PUFA content by 40%KCl(P>0.05).2.Influence of partial substitution of NaCl by 40%KCI on volatile compounds changes during processing analysed by electronic nose.Electronic nose was employed to determinate the different volatile odor changes between substitution group and non-alternative group.Whether in semimembranosus or in biceps femoris,methane sensor S6,sulfide sensor S7,aromatic compounds sensor S8?S9 show relatively higher relative resistivity values(G/G0)than other sensors.So they were regarded as key sensors in this study.It showed that aromatic compounds,alcohol,sulfide,hydrocarbons content were increased by 40%KCl in dry-cured hams.Principal component analysis(PCA)and Linear discriminant analysis(LDA)showed a clear discrimination on all sampling stage.With closer points and higher contribution rate,LDA indicated more accurate discrimination and was considered suitable for the analysis.LDA showed that the formation of volatile flavor compounds was significantly influenced by 40%KCl substitution,such as methane?sulfide and aromatic compounds,but how it affects the need to combine the results of further analysis of GC-MS.3.Influence of partial substitution of NaCl by 40%KCl on the formation of volatile compounds during processing analysed by GC-MS.Influence of partial substitution of NaCl by 40%KC1 on the formation of volatile compounds in dry-cured ham was evaluated using a headspace purge and trap GC/MS system.Semimembranosus muscle and Biceps femoris muscle were sampled randomly from five stages.The results indicated that:the formation of volatile compounds in substitution group was slower than control group.But some key compounds,such as lipid derivative compounds(hexanal)and Strecker degradation of aldehydes(2-methylbutyraldehyde and 3-methyl butyral)were significantly(P<0.05)higher than 100%NaCl groups,suggesting that potassium promotes lipid oxidation,which was consistent with the findings of the first chapter.In addition,the influence of partial substitution of KCl on alcohol and sulfur compounds was the same with findings by electronic nose.However,no significant difference of compounds content was found between two treatments in final product,indicating that 40%KCl subtitution of NaCl was feasible.In sensory evaluation,all sensory index were not influenced by KCl except saltiness,5.09±0.27(control group)>4.01±0.41(substitution group).The evaluation of red,yellow,hardness,juiciness,odor intensity,bitterness and aftertaste were not significantly affected,indicating that 40%KCl substitution of NaCl can not only decrease the NaCl content but also keep the original flavor of tranditional ham and even promote the sensory evaluation.