Effect Of Complex Plant Essential Oil Coating On Antimicrobial And Antioxidant And Texture And Flavor Quality Of Dry-cured Ham

There are some problems such as inhomogeneity between biceps femoris muscle and semimembranosus,high peroxide,severe microbial growth existence in the processing of traditional ham.Existing research already use animal and plant oil coating,chitosan coating to inhibit excessive lipid peroxidation and excessive water loss during the ripening of ham.In order to improve the uniformity and flavor quality of the inside and outside texture of ham,however,the method had little effect.Plant essential oil which now has already been widely used in food processing and storage can improve the function of antioxidation and bacteriostasis.This study is based on the preliminary work in our laboratory to prepare the special coating material for ham use lard and starch as base material and plant essential oil as antioxidant.In the middle of ripening,coating the surface of ham to inhibit the growth of ham lipid oxidation and microbial growth,improve product texture homogeneity and flavor quality,provide theoretical basis and technical support for the modern processing technology of ham.coating.1.Study on the effect of complex plant essential oil coating cooperate with intensify high temperature on the antioxidation and texture of hamUse pork as raw materials,lard and starch as base material for antioxidant coating,litsea cubeba oil and cinnamon essential oil for preparation of antioxidant coating material.Study on the antioxidation and texture and antibacterial activity of compound essential oil coating combined with intensify high temperature ripening process through orthogonal test.The optimized results show that the ratio of Litsea cubeba oil and cinnamon oil is 1:1,compound essential oil content is 0.05%(by weight of coating material).Under the 35? of ripening process,TBARS,the total number of colonies and mold for semimembranosus of coating group respectively is 0.549 mg MDA/kg,3.662(lgCFU/g)and 1.341(lgCFU/g).Uncoated group(0.722MDA/kg,5.255(lgCFU/g),2.368(lgCFU/g))drop 24%,31.1%,43.4%respectively.The difference of moisture content,aw and hardness between semimembranosus and biceps femoris muscle in the coating group were respectively 2.59,0.031,and 6.66,respectively.Compared with non coated group which is 4.43,0.086,10.36,respectively,decreased by 41.5%,64%,35.7%.And when the mixture ratio is 1:0.5?1:2,addition amount of compound essential oil is 0.03%?0.05%had good inhibitory effect.Also compound essential oil coating can significantly reduce the ham moisture,water activity and hardness difference between semimembranosus and biceps(P<0.05).These results show that the antioxidant coating can effectively improve the uniformity of the internal and external structure of the ham,and plant essential oil can significantly reduce the lipid oxidation and inhibit the growth of microorganisms in semimembranosus.2.Effect of complex plant essential oil coating cooperate with intensify high temperature on the volatile flavor compounds of hamThe electronic nose method was used to analyze the odor changes of dry cured ham between the coating and no coating groups.The effect of coating and no coating on the volatile flavor compounds in dry cured ham was studied.The results showed that the compound essential oil coating could improve the flavor characteristics of aromatic,alkane and terpene compounds in ham,and decrease the flavor characteristics of nitrogen and organic sulfide compounds.The volatile flavor compounds of coating group and non coating group of dry cured ham separated and identified by solid phase micro extraction and gas chromatography-mass spectrometry in order to study the effects of compound essential oil coating on the formation of flavor between semimembranosus and biceps in dry cured ham.The results showed that in semimembranosus,except ketones flavor,the count of flavor in coating groups were higher than that of the uncoated group,and extra flavor substances were 5 hydrocarbons,2 alcohols,1 esters,3 acids,1 aldehydes and other 2 species.Totally increased 15 flavor compounds in ham semimembranosus,specifically are dipentene,terpinenes,cedrene,cadinene,?-styrene,benzyl alcohol,cinnamic alcohol,cinnamic aldehyde,oleic acid,propionic acid,butyric acid,cinnamic acid ester,phenol,p-cresol,which have positive role to the flavor characteristics of ham.At the same time,GC-MS results showed that the composite coating on the quantity and relative contents of volatile flavor compounds in biceps were not significant(P<0.05),but increased the relative content of characteristic flavor compounds in semimembranosus such as 1-octene-3 alcohol,2-methyl-1-butanol,3-methyl aldehyde,2-octenal etc.Therefore,it can be observed that complex essential oil coating cooperate with intensify high temperature air drying ripening technology can be used in the air drying ripening of ham.