In the present study,the effect of lipid content and oxidation on the color of casing was investigated.Result showed that lipid content has a significant impact on the color of casing.After alcohol treatment,lipid content of casing decreased while its △E decreased significantly.The correlation coefficients for the colour change and the lipid oxidation of casing over 0.9.The present study indicates that lipid oxidation is an important factor of the deterioration of casing's color.

Based on the single factor experiments,the orthogonal experimental was designed to optimize the experimental condition of the effect of sonolysis and ozonation on the degradation of chloramphenicol in casing,with the degradation degree of chloramphenicol as the indicator.Results showed that the ozonation time had the great effect on the degradation of chloramphenicol.Under the condition of ozonation time 25 min,sonolysis time 15 min,sonolysis frequency 80 kHz,the highest degradation degree of chloramphenicol in casing was observed and the color and the texture of the casing were not influenced.The effect of sonolysis combined with ozonation could degrade the residual chloramphenicol in casing effectively.

In this study,the strain C94 with the function of protein hydrolysis was screened from traditional air-dried duck and applied in duck sausage.The physical and chemical indicators of the sausage during the process of maturation were determined.Compared with naturally fermented group(CK) with Saprophytic staphylococcus fermented duck sausages,the aw and pH of C94 fermented duck sausages revealed a rapid decrease,however,the amount of aspartic acid,glutamic acid,tyrosine and lysine revealed an obvious increase.The amount of lysine was up to 135.68 mg/100 g in C94 fermented duck sausages,and was only 37.32 mg/100 g in the CK group.The types and amounts of volatile compounds in Saprophytic staphylococcus fermented duck sausages was analyzed by solid phase microwextractiongas chromatography(SPME/GC-MS).Totally 69 kinds of flavor substances were identified in Saprophytic staphylococcus fermented duck sausages,which included 23 kinds of aldehydes,15 kinds of hydrocarbons,7 kinds of alcohols,3 kinds of acids,6 kinds of esters,4 kinds of ketones and others.

Effects of Staphylococcus saprophyticus CGMCC 3475 as starter culture on lipolysis-oxidation and quality of fermented pork loin during processing(fermented for 30d,50d,70d,90d and 110d) were studied,with non-inoculated pork loin as control.Lipolysis-oxidation and its correlation during fermenting were studied by analyzing free fatty acids(FFA),thiobarbituric acid(TABRS),diene value and carbonyl value.Volatile flavor compounds such as aldehydes and ketons were also studied.The results showed that the content of SFA,MUFA and PUFA of the inoculated pork loin increased significantly(P<0.05) than that of in the non-inoculation during fermenting except at 50 days.Content of SFA and PUFA of both samples reached highest value at 90 days,and content of MUFA increased throughout the fermenting.TBARS value decreased throughout the fermenting but increased at 70 days.Carbonyl value and diene value increased during fermenting,and both values of the inoculation were higher significantly(P<0.05) than the non-inoculation.Compared to control fermented pork loin,less linear chain aldehydes and ketons but 56.7% esters were detected in the inoculated pork loin at 70 days,while the content of linear chain aldehydes and ketons were significantly higher(P<0.05) during other fermenting stages.

In order to get the reason of red change in salted casing,a strain that produces red pigments was isolated from the red salted casings after repeated streak plate and purification,through halophilic bacteria and halophilic bacteria selective medium.Based on morphological,physiological and biochemical tests,the strain was identified as Halobacterium sp.

Three type of antioxidant with different concentrations were individually applied in the study of fat oxidation and color property of nature casings.The result showed;0.005%BHT,0.02%V_E and 0.005%sodium erythorbate had a good effect to inhibit fat oxidation and to protect color fading than other testing groups.Mixture design methodology was used to optimize antioxidant composites formula,the proportion of every antioxidant were limited in the range of 0.005%to 0.01%.The regression model of relationship between proportion and color rate of K_(ΔE) was also established.The result were that treated with the combination of 0.005%BHT,0.01%V_E and 0.005%sodium erythorbate,K_(ΔE) was the smallest and casing's color was the best.