Changing Of Lipids And Flavor Compounds During Modern Processing Of Jinhua Ham

Jinhua ham is a kind of famous traditional food in our country. The special flavor of Jinhua ham is popular with the consumers. But under-developed and original methods were used to product Jinhua ham long ago. It limited the development of the production of Jinhua ham.Today, the meat product market has been connected with the foreign market. If we want to save and develop the traditional and special meat product of our country in surroundings of cut -throat competition, we should take an intensive study and use the modern science and technology to reform and improve the traditional production engineering. During the production capacity of Jinhua ham developed faster and faster, the"Shuangtouwu"pig as the material of Jinhua ham became fewer and fewer. Meanwhile, it can't fulfill the normal need as thematerial of Jinhua ham. So it is necessary for us to make a technology standard of searching legs of hybrid pigs as the material of Jinhua ham.The effect of lipids to the product during processing of modern dry-cured Jinhua ham is mainly studied in this subject. Three production engineerings is designed by selecting two types of material legs, normal weight legs and normal weight legs with thick fat, and taking two types of processing methods with low salt content and high salt content. Production engineering one is selecting normal weight legs and treating with high salt content. Production engineering two is selecting normal weight legs and treating with low salt content. Production engineering three is selecting normal weight legs with thick fat and treating with high salt content. Seven processing points are selected during the processing which are material, curing, drying, maturation one, maturation two, maturation three and after ripening. And three positions are selecting in each processing point which are biceps femoris muscle and subcutaneous fat. The changes of lipids during processing of Jinhua ham were studied through testing endogenous enzyme activity, free fatty acid, TBA and flavor compound as well as the effect of lipids on Jinhua ham's flavor. In order to supply theory basis for optimized modern processing of Jinhua ham, comparing with different materials and different treatments of salt content effect on Jinhua ham. Meanwhile, compare with Jinhua ham's some relative indexes produced by modern and traditional processing.Hydrolysis process was understood through studying the changes of endogenous enzyme activity during the processing of Jinhua ham. The results show that endogenous enzyme activity was descending during the whole processing. The downward trend of endogenous enzyme activity is obviously before maturation one period, and after that period this trend became slower. For example, in biceps femoris muscle of group B, the endogenous enzyme activities declined from 15.7, 13.1, 10.3 in material to 4.83, 4.86, 2.43 in drying, and then declined to 0.09, 0.44, 0.03 after ripening. The changes of endogenous enzyme activity during the modern processing are similar with the changes during the traditional processing. But the speed of the changing is obviously becoming faster.The hydrolysis and oxidation of lipids during the modern processing was understood through testing free fatty acid and TBA. The results show that the content of FFA was increasing during the whole processing. The rising trend of FFA's content is obviously before drying period, and after that period this trend became slower. For example, in biceps femoris muscle of group B, the total FFA's content rase from 3.85% in material to 6.57% in drying, and then declined to 7.70% after ripening. TBA was also rising at first, and reached the summit in the drying period, then descended at last. For example, in biceps femoris muscle of group B, the TBA rase from 0.009μg TEP/g in material to 0.057μg TEP/g in drying, and then declined to 0.030μg TEP/g after ripening. According to the processing of traditional Jinhua ham, the changes of parameters were similar.Flavor compounds in biceps femoris muscle and subcutaneous fat were isolated and identified by SPME and GC-MS. The results show that the flavor compound tested during the production can be classified as hydrocarbons, alcohols, aldehydes, ketones, acids, esters, oxygen-heterocyclic compounds, sulfur compounds, nitrogen compounds. Aldehydes and ketones had more kinds than any other flavor compounds. There were both 42 kinds of flavor compounds. And the content of hexanal was highest among all flavor compounds. In biceps femoris muscle of three groups, the content of hexanal were 61.4% of group A,66.1% of group B and 48.1% of group C. Comparing with the results during the traditional processing of Jinhua ham, the kinds of flavor compounds tested in this subject were fewer. But the main flavor compounds could be found in the results of this subject, and the content of these main flavor compounds occupied the leading position.On the basis of the above-mentioned results, comparing with different materials and different treatments of salt content effect on Jinhua ham, it was found that the products by selecting normal weight legs with treatment of low salt had better flavor.