Effects Of Ultra-High Pressure Treatment On Shelf Life Of Water Boiled Salted Duck

Chinese Nanjing water boiled salted duck is one of the few low temperature cooked meat products in traditional Chinese featured meat products. It is favored by consumers because of its delicate taste, savory, and tender meat. Considering features of low temperature cooked meat products, one of difficulties met by industrial producers is the very short shelf-life of water boiled salted duck. Many factories which process ducks usually applied post-production treatments into duck products after vacuum packing in order to prolong the self-life. General post-production treatments are for example, heating, micro-wave, radiation, etc, but all these treatments influence much the flavor and sensory which influence consequently the market for these water boiled salted ducks following post-production treatments. As a physical treatment, ultra-high pressure has almost no influence on food’s quality and can keep nutritions in food. It may be applied on post-production treatment for water boiled salted duck.This study concentrated on the effects on sensory, shelf-life, flavor of salted duck after different ultra-high pressure post-production treatment, aiming to afford theoretic proves for ultra-high pressure post-production treatment parameters for water boiled salted duck. The contents and results were as follows:1Effects of different boiling temperature on quality of water boiled salted duckThe vacuum-packaged duck breasts were cooked at80℃,85℃,90℃,95℃and a series of analysis relating to sensory, microbiology, quality index were practiced. According to the results, the product cooked at90℃was most appreciated in sensory analysis:Its flavor and tenderness were better than products cooked at other temperature. Total counts of spoilage microorganisms obviously decreased along with increase of boiling temperature (P<0.05). Changes of boiling temperature had no influence on color and pH value of product. Considering all analysis results,90℃(centre temperature of product attended at81℃) was regarded as the best boiling temperature for water boiled salted duck. Product boiled at90℃show a delicate savory and there is no many microorganisms in it.2Effects of ultra-high pressure treatment combined with temperature on shelf-life of water boiled salted duck In order to understand the effects of ultra-high pressure (UHP) treatment on the shelf-life and quality index of water boiled salted duck, the vacuum-packaged duck breasts were subjected to UHP(200and400Mpa) treatment at20℃、30℃、40℃for10min. The analysis results showed that UHP treatment combined with temperature could effectively inactivate initial microorganisms and inhibit growth of microorganisms in water boiled salted duck breast during storage at0-4℃. Therefore, self-life of products was prolonged. In addition, the results also indicated that UHP treatment has no evident influence on pH value and color of products (P>0.05). TBARS increasing was evidently observed in400MPa-treated breasts (P>0.05). Considering all analysis results,200MPa/40℃was suggested in industrial post-production treatment as UHP parameter for vacuum-packed water boiled salted duck. Shelf-life of products after UHP treatment stored at0-4℃could attend more than12weeks.3Effects of ultra-high pressure treatment on flavor of water boiled salted duckIn order to understand the effects of ultra-high pressure treatment (UHP) combined with temperature on flavor, water boiled salted duck breasts treated by200MPa and400MPa at20℃、30℃、40℃were checked by PEN3electronic-nose (AIRSENSE). The electronic-nose responding results to UHP treated products and untreated product were analyzed by PCA method、loadings and LDA method. The results indicated that electronic nose could effectively induct odor of Nanjing salted duck and products treated by200MPa/40℃or400MPa/20℃had a similar odor with the untreated one.