| Xuanwei Ham is a famous local meat product of high quality in China. In this paper, the reasons for the quality formation of traditional ham are studied and the standardized producing experiments are carried out. The standardized producing system is first established, which lays a solid foundation for the standardization and industrialization of this traditional product. The results show that the ratio of finished product of traditional Xuanwei Ham is 69.30%~75.66% and that the water content, salt content and aw in ripened ham and subcutaneous fat are 44.22%~53.04% and 2.47%~2.76%, 8.70%~13.10% and 0.73%~0.85%, 0.785~0.845 and 0.755~0.805 respectively. The free amino acid content in M. semimembranosus and M. Biceps semoris dry matter are 5922.18 mg 100g-1 and 10475.83 mg 100g-1 separately. By using SDE and GC-MS, 84 volatile compounds are tentatively identified in traditional Xuanwei Ham.As a unique local product, the producing condition of Xuanwei Ham is firmly related to the natural climate and material quality. The standardized producing technology is determined by the principle of cured ham and climate character of producing traditional Xuanwei ham. The standardized curing technology is as follows: the green hams are refrigerated and held for 48 h at 0-4℃ after slaughter, salted for 28 d at 0-4℃ and RH 75%~90%, post-salted for 30-60 d at 0-4℃ and RH 60%~75%, dried for 60 d at 10~15℃ and RH 50%~65%, ripened at 15-20℃ for 120-150 d at 15-20℃ and RH 60%-75%. Experimental results indicate that the standardized producing technological conditions of Xuanwei ham can meet the requirements of standardized production all the year round.The water content, salt content and aw in M. semimembranosus and M. Bicepts femoris of the standardized producing hams are 40.32% and 51.26%, 7.77% and 10.15%, 0.839 and 0.839 respectively. The yield of ripened hams is 76.26%. Ripened hams made by standardized producing technology have the characters of traditional Xuanwei ham: pure flavor, sweet aroma, low salt as well as high-grade sanitation quality.With the ripening process of Xuanwei ham, the volatile compounds identified from M. semimembranosus and M. Bicepts femoris of the ripened hams at 12 months are 98 and 67 respectively. The content of the volatile compounds reaches highest at 6 months and then decreases. The contents of volatile compounds in M. semimembranosus and M. Bicepts femoris dry matter are 9240.16 ug nonane 100g-1 and 13227.85 ug nonane 100g-1 respectively at 6 months. Aldehydes are primary compounds in process of Xuanwei ham, in which the tiptop content is 6744.60 ug nonane 100g-1 and 11326.18 ug nonane 100g-1 in M. semimembranosus and M. Bicepts femoris dry matter at 6 months, and then drops. Aldehydes have made great contributions to the flavor of Xuanwei ham because of their low flavor threshold value.Many special volatile compounds are identified in muscle of Xuanwei ham by comparison of other reports. They are unsaturated hydrocarbons, unsaturated aldehydes with long carbon chain, furan ketones, and methyl esters, ethyl esters formed unsaturated fat acids with long carbon chain.Heterocyclic compounds and containing sulphur compounds, the important flavor compounds for dry cured ham, are also identified from the muscle of Xuanwei ham. They are 2-ethyl-furan, 2-pentyl-furan, methyl-pyrazine, 2,6-dimethyl-pyrazine, dimethyl-trisulfide, diethyl-trisulfide, 3,5-dimethyl-1,2,4-trithiolane and 3-phenyl-thiophene etc.The standardized producing system is based on the results of standardized producing Xuanwei ham. The sensory evaluation, physicochemical and microorganism index of Xuanwei ham are drawn up. The maximum residue limit for veterinary drug, pesticides, heavy metal and nocuous matter are restricted and signs, package, transport and storage of Xuanwei ham have also been prescribed. Besides, some suggestions on production and quality of raw material are put forward. |
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