| Duck meat is one of the three major meats in China and has high nutritional value.Sauce-marinated meat products are typical traditional meat products in China.They are popular among consumers because of their attractive color and rich flavor.Atmospheric high temperature marinating is often used,and quantitative marinating or ultrasonic assisted marinating technology is also used to improve the quality.Sous-vide cooking(SVC)technology uses vacuum conditions to isolate environmental oxygen,and completes cooking operations at relatively mild and controllable temperatures(50～90℃),making the products tender and juicy and reducing microbial contamination.The research on SVC technology mainly focuses on beef,pork,mutton,chicken,fish,etc.,while the research on duck meat is relatively few.With the rise of prepared dishes and the emergence and promotion of ready-to-eat products,the formation mechanism of catering cooking quality needs to be further explored.The integration of modern food analysis method and food industrial processing technology will promote the development of food industry.In this study,duck meat was used as raw material,typical sauce marinated meat formula was used to process marinated duck by SVC,fuzzy mathematical sensory evaluation method combined with orthogonal test was used to optimize the processing technology of SVC marinated duck,analyze the changes of SVC technology on the flavor and quality characteristics of marinated duck during storage,and explore the effects of SVC conditions on the gel characteristics of duck muscle fibrillar protein(MP).To provide scientific theoretical guidance for quality control of SVC marinated duck during processing,production,storage and transportation.The main research contents and results are as follows:(1)Taking marinating temperature(60～80℃),marinating time(30～150 min)and solid-liquid ratio(1:0.5～1:2.5)as single factors,fuzzy mathematical sensory evaluation method combined with orthogonal test was used to optimize the processing technology of SVC marinated duck.The results showed that the order of influencing factors of SVC marinating technology was: marinating temperature>marinating time>solid-liquid ratio,and the best SVC marinating conditions were: marinating temperature 70℃,marinating time 105 min,solid-liquid ratio 1:1.75.The sensory score of the SVC marinated duck was 89.03 points,the yield was 69.52%,the L* value was 65.04,the a* value was 5.88,the b* value was 15.76,the hardness was 1092.28 g,the adhesive value was 603.86,the chewability was 425.18,the elasticity was 0.697 mm and the shear force was 6.13 N.SVC marinated duck with this process has uniform color,bright luster,rich aroma and marinated flavor,and tender and chewy meat.(2)The effects of different marinating temperatures(60～80℃)on the flavor quality of SVC marinated ducks were analyzed by electronic nose and gas chromatography-mass spectrometry(GC-MS).The results showed that the electronic nose response signal values of SVC marinated ducks at different marinating temperatures were significantly different(P<0.05),which could be used to better analyze the difference of flavor of SVC marinated ducks at different marinating temperatures.A total of 16 kinds of free amino acids were detected in SVC marinated ducks at different marinating temperatures,and the total content was 234.97～270.60mg/100 g,which showed a trend of first increasing and then decreasing(P<0.05),and was significantly higher than that in the control group(P<0.05).The total free amino acid content of SVC marinated ducks at 70℃ reached the maximum value.Six kinds of nucleotides and degradation products were detected in SVC marinated ducks at different marinating temperatures,among which the content of flavor nucleotides was between32.88 and 41.08 mg/100 g,the overall trend was first increased and then decreased(P<0.05),and the content of flavor nucleotides reached the maximum value at 70℃.A total of 7 kinds of free fatty acids were detected in SVC marinated ducks at different marinating temperatures,among which the content of saturated fatty acids(SFA)decreased first and then increased,but all of them were lower than the control group;the content of unsaturated fatty acids(UFA)increased first and then decreased,but all of them were higher than the control group.The contents of C16:0,C18:1 and C18:0accounted for more than 75% of the total fatty acids.It has important contribution to the flavor of SVC marinated duck.75,73,81,78 and 80 kinds of volatile flavor substances were detected in SVC marinated ducks at different marinating temperatures,and the most volatile flavor substances were found in SVC marinated ducks at 70℃.Aldehydes(mainly n-nonal,n-hexal,1-octanal,n-heptanal,cetylaldehyde)and alcohols(mainly linalool,ebulliol,n-octanol,1-octene-3-ol,(-)-4-terpenol,α-terpineol)were the main characteristic volatile flavor substances,accounting for 80.18%,among which aldehydes accounted for 52.58%.It plays a leading role in the whole aroma of marinated duck.In conclusion,SVC technology can promote the release of free amino acids and inhibit the oxidative degradation of UFA.Among them,SVC marinated duck at 70℃ has the most abundant taste substance and flavor substance.(3)The effect of different SVC temperatures(60～80℃)on the characteristics of MP gel of duck meat was analyzed,and the formation mechanism of MP gel quality was discussed.The results showed that the whiteness,water retention and chemical force of MP gel were significantly higher than those of control group(P<0.05).With the increase of SVC temperature,the water retention,hardness,chewability,adhesivity and elasticity of MP gel of duck meat increased first and then decreased,and all reached the maximum at SVC temperature of 70℃.With the increase of SVC temperature,the cooking loss rate of MP gel of duck meat gradually increased,but was significantly lower than that of control group(P<0.05).The chemical force gradually decreased,gel pore size gradually became smaller,the network structure became clearer and more regular,the contents of α-helix and β-angle gradually decreased,and the contents ofβ-folding gradually increased.In conclusion,SVC technology can improve the properties of MP gel of duck meat,so as to improve the quality of marinated duck.(4)Taking the short-time brining at atmospheric pressure and high temperature as the control group,the changes of physicochemical indexes and microbial indexes of SVC marinated ducks during storage under the condition of refrigeration at 4℃ were investigated.The results showed that the moisture content and pH of SVC marinated ducks decreased first and then increased(P<0.05)during 10 days of storage.The value of L* decreased gradually,while the value of a* and b* increased gradually,and the change of b* was not significant(P>0.05).The hardness,chewability and adhesivity increased first and then decreased,but the elasticity had no significant change(P>0.05).TVB-N value and carbonyl content increased gradually,while sulfhydryl content and sensory score decreased gradually,but the overall change trend of experimental group was slow.The total number of colonies was significantly increased(P<0.05),and the control group exceeded the limit on the 8th day,while the experimental group approached the limit on the 10th day.In conclusion,SVC technology is helpful to prolong the shelf life of marinated duck under cold storage. |
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