| In this paper,the changes of main nutrient ingredients and edible security of cured-meat were studied.The cured-meat was supplied by Baile limited company of Chongqing.The cured-meat was divided into A groups and B groups(adding ascorbic acid) and packed by vacuum treatment separately.Then respectively were stored in the refrigeration storage(5℃) and in the frozen storage(-18℃).The results are as follows:1.The changes of the nutritional value of cured-meat during the refrigeration storage(1) The change of water contentDuring the whole refrigeration storage,the water content of the fat and lean cured-meat was down trend.The water content of fat cured-meat of A group and B group decreased respectively from 5.84%to 3.34%and from 5.84%to 3.07%.The water content of lean cured-meat of A group and B group respectively decreased from 47.28%to 44.17%and from 47.28%to 43.82%.(2) The changes of fat content and fatty acid compositionDuring the whole refrigeration storage,the crude fat content was downtrend.The crude fat content of fat cured-meat of A group and B group respectively decreased from 88.98%to 88.61% and from 88.98%to 88.54%,and the free fatty acid content respectively increased from 4.11mg/g to 6.17mg/g and from 4.11mg/g to 5.12mg/g.The free fatty acid content of A group were higher than B group during the whole refrigeration storage.That showed that adding ascorbic acid can inhibit the hydrolysis of fat.The fatty acid composition analysis of fat cured-meat showed that oleic acid content was the highest,followed by palmitic acid＞stearic acid＞linoleic acid＞palm oil methyl ester＞myristic acid＞allyl methyl＞linolenic acid.SFA:MUFA:PUFA of A group was 1:1.25:0.25 and B group was 1:1:0.17.n-3 fatty acid/n-6 fatty acids of A group was 1:18.9 and B group was 1:6.5.which showed the main degradation of fat was unstable PUFA during the refrigeration storage,and the fatty acid composition of B group(adding ascorbic acid) was better than A group. (3) The changes of protein and amino acid contentAfter refrigeration storage 120 days,the protein content was gradual downward.Protein content of A group and B group respectively decreased from 37.52%to 29.76%and from 37.52%to 31.74%.Seven kinds essential content of A group and B group increased from 9.828g/100g to 13.745g/100g and from 9.828g/100g to 15.632g/100g.E/N ratio increased from 0.65 to 0.75 and 0.72 respectiely,and the nutritional value of products had been improved.The amino acids total,essential amino acids and amino acids cents of added ascorbic acid group were significantly higher than without added ascorbic acid group.That showed that adding ascorbic acid can inhibited decomposition of amino acids.2.The changes of the nutritional value of cured-meat during the frozen storage processing(1) During the whole frozen storage,the water content of the fat and lean cured-meat were downtrend.The water content of fat cured-meat of A group and B group respectively decreased from 5.84%to 3.74%and from 5.84%to 3.37%.The water content of lean cured-meat of A group and B group respectively decreased from 47.28%to 44.19%and from 47.28%to 43.38%.(2) The changes of fat content and fatty acid composition.During the whole frozen storage,the crude fat content fat cured-meat of A group and B group respectively fell from 88.98%to 87.56%and from 88.98%to 87.64%.The free fatty acid content of A group and B group respectively increased from 4.11mg/g to 7.05mg/g and from 4.11mg/g to 6.98mg/g.the increasing rate were respectively 69.9%and 71.5%.The different treatment was no significant difference(p＞0.05).That was showed added ascorbic acid had little effect on degradation of fat.The results of fatty acid composition and content of fat cured-meat with A group and B group as follows:oleic acid＞palmitic acid＞stearic acid＞linoleic acid＞palm oil methyl ester＞allyl methyl＞myristic acid＞linolenic acid,The content of allyl methyl was higher than myristic acid,which was different from refrigeration storage.That showed that allyl methyl released was more than myristic acid during the whole frozen storage.SFA:MUFA:PUFA of A group and B group is separately 1:1:0.22 and 1:1.11:0.22;and n-3 fatty acid/n-6 fatty acid is separately 1:5.8 and 1:4.6,both ratio of n-3 fatty acid/n-6 fatty acid are in advised area,A group is lower than B group.It indicated that adding ascorbic acid under the condition of frozen storage have little effect on fatty acid constitute.(3) About the changes of protein and amino acid content.After storage 120 days,the protein content was gradual downward.A group and B group of protein content respectively decreased from 37.52%to 25.58%and from 37.52%to 26.19%. After frozen storage 120 days,the content of protein and amino acid in group A and group B is respectively increased,the content of essential amino acids increased from 9.828g/100g to 11.815g/100g and from 9.828g/100g to 14.048g/100g.respectively,E/N decreased from 0.65 to 0.64,above 0.60 in group A;E/N imcreased from 0.65 to 0.71 in group B,above 0.60,too.The nutritional value of products has been improved at some extent.After frozen storage 300 days, total content of amino acid and essential amino acid are decreased,the content of A group even less than the origination value.It is found that the total content of amino acid and essential amino acid are higher in the group adding ascorbic acid than in the group adding nothing.3.About the changes of ascorbic acid during low temperature storage:The content of vitamin C of bacon that adding ascorbic acid and vacuum treatment and respectively stored at 5℃and -18℃for 120 days dropped 26.5%and 39%,it indicated that temperature have some effects on the disassemble of vitamin C,at -18℃decomposed fast.The content of vitamin C dropped 44%when frozen storage to 300 days at -18℃,It indicate that vitamin C can be use for low-temperature preservation of bacon,and as antioxidants is more suitable for adding into bacon under the cold storage condition.4.About the changes of edible security indexes of cured-meat during refrigeration storage:(1) Analyzed on the index of fat degradation during bacon low-temperature storageAV,PV and TBA are rising during bacon cold storage,the AV of group A and group B is respectively increased by 3.11 mg KOH/g and 2.71mg KOH/g,the PV is respectively increased by 3.48×10-5g/100g and 3.04×10-5g/100g.The TBA is respectively increased by 6.17mg/g and 5.82mg/g.It indicated that adding ascorbic acid under the condition of cold storage is in favor of restrained fat degradation,staved bacon rancidity and long time storaged.AV,PV and TBA are rising during bacon frozen storaged,the AV of group A and group B is respectively increased by 3.51 mg KOH/g and 3.50mg KOH/g,the PV is respectively increased by 4.31×10-5g/100g and 4.29×10-5g/100g.The TBA is respectively increased by 6.93mg/g and 6.89mg/g.It indicated that adding ascorbic acid under the condition of frozen storage is little effect on fat degradation.(2) Analyzed on the index of protein degradation during bacon low-temperature storageDuring the whole refrigeration storage,the content of volatile nitrogen was uptrend.After cold storage 120 days,A group and B group respectively increased by 25.99mg/100g and 24.04mg/100g.After frozen storage 300 days,A group and B group respectively increased by 23.63 mg/100g and 23.27 mg/100g.Adding ascorbic acid have some restrain effect on protein degradation.(3) Changes of the nitrite during bacon low-temperature storageDuring the whole refrigeration storage,the nitrite content was evident downtrend,after 120 days,A group and B group respectively decreased by 7.84 mg/kg and 5.87 mg/kg;after 300 days, group A and group B respectively decreased by 6.09 mg/kg and 6.13 mg/kg..It indicated that adding ascorbic into bacon is in favor of reduced the content of nitrite in bacon.(4) Conclusion:Compared with the relevant standards,the index of fat degradation during low-temperature storaged is still in safety edible,the index of protein degradation accord with 2 product≤45 mg/kg in SB/T 10294-1998,It indicated that in this experiment,bacon can be storaged 4 months at 5℃and 10 months at -18℃.
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