Research On Producing Sliced Ham By Modulating The Exogenous Enzyme Activity

The aim of this research was to keep the traditional dry-cured ham's special and character flavor,while accelerating the produce of flavor precursors,reducing salt content, shorting its production cycle. A new type of sliced ham which have the traditional dry-cured ham's flavor profile was produced by addition exogenous enzymes.The main content and results are as follows:The effects of exogenous proteases and lipases on flavor of sliced ham were studied.Tastes and component precursors were quickly produced by addition exogenous proteases and lipases.Single factor experiment and orthogonal test analysis showed that the optimum conditions were:the dose of proteases 4900U/100g,salt 6%,neutral lipase 240U/100g and hydrolysable time 48 h.There were amic nitrogen(AN)321.45 mg/100g and free fatty acids (FFA)1.31% of the hydrolysable sample in the optimum condition. Sensory evaluation indicated the taste was good and aroma was weak in the the hydrolysable sample.Later,by research the enzyme samples oxidation under different temperature and time, the optimum mature condition was choosed for 28℃,40d.At the end of the mature, the sliced ham taste good and have a better ham flavor.Comparison of sliced ham with enzymes and the control group in physiochemical indexes were studied.From it we can find the influence of exogenous enzymes to protein, fat degradation and flavor substances intuitively. The result showed that in protein degradation aspect, exogenous enzymes significantly increased AN and NPN content(P<0.05) ,but TVB -N changed not obvious(P>0.05).In lipid degradation and oxidation aspect, we can inferred that exogenous enzymes accelerated the fatty acids content and affect the oxidation reaction by AV, TBA value and POV increased. Sensory evaluation showed that the sample with exogenous enzymes had a better flavor than the control group after oxidation. Also the free amino acid (FAA) content during the processing of the slicd ham was reaserched, and we can find that the sliced ham had a similarity degree to jinhua ham in FAA constitute by compara the two group, Therefore, the use of exogenous enzyme can increased flavor precursor substances rapidly, and has magnificent significance to the formation of dry-cured ham's special flavor.Sliced ham were compare to the traditional dry-cured ham by analyzing flavor composition by SPME-GC-MS and Triangle test sensory evaluation.The results showed that: the sliced ham have 59 types of volatile flavor components while the traditional dry-cured ham have 65. the sliced ham accepting of the sliced ham was good but aroma was weak. sensory evaluation indicated that there have no significant difference between the two at the 1% level.The GC-MS flavor profile analysis objectively proved that the sliced ham flavor profile was consistent with that of raw ham.There were mostly flavor and unique flavor of traditional dry-cured ham,and the content was consistent with that of raw ham in the sliced ham.