Effect Of Variable-temperature Fermentation On Quality Of The Smelly Mandarin Fish And Study On Components Of Fermentation Gas

The mandarin fish is one of the representative dishes of the Anhui cuisine.The traditional Chinese cuisine and the fish are garlic-like,nutritious and delicious,but there is no uniform production standard.It is difficult to make the industrialization because of its production mode.The effect of the fermentation method on the quality of the fish and the research on the gas composition of the fermented mandarin fish is less.The research of this paper can provide some reference value and theoretical basis for the standardization and industrialization of the mandarin fish.Based on the traditional method of constant temperature fermentation,the physical indexes,regular chemical indexes and histological indexes of the fish were studied by the method of variable temperature fermentation.The control group(constant temperature fermentation)was fermented for 8 days.(Incubation temperature fermentation)were set up in experimental group 1 and experimental group 2,which were fermented for 7 days;the study of fermentation during fermentation fermentation gas composition changes:constant temperature fermentation for 7 day.The changes of fish meat quality and fermentation gas composition were carried out.The results were as follows:(1)The effect of segmental fermentation on the quality of mandarin fish was found that the p H of the 7th day and 6th day of fermentation was about 6.8 both in the experimental group and control group,and the change trend was similar during the fermentation.At the sensory level,the sensory value and the color was similar,the hardness was the highest at 7th day and 6th day both in experimental group and control group.the hardness of the experimental group 2 and the control group were1838.97 g and 1779.85 g,respectively.Cohesion,chewiness,elasticity and other indicators are consistent with their hardness trends.The analysis of the conventional chemical indexes of fish,we can see the crude fat and crude protein showed a decreasing trend under the two fermentation methods,and the descending trend of the experimental group was lower than that of the control group,and the early stage of fermentation decreased rapidly and the later stage was relatively slow.The content of crude protein of 7th day in control group decreased from 18.32% to 16.68%,and the protein content of 6th day in experimental group 1decreased from 18.43% to 16.82%.The analysis of histological indexes showed that the transverse section of the muscle microstructure in the experimental group 1 was consistent with that of the control group at the 7th day.Finally,the gray correlation analysis method was used to analyze the fish quality,find that the experimental group1 for 6 days(correlation degree 0.8)was similar to the control group for 7 days.It can be seen that the variable temperature fermentation with the traditional type of temperature fermentation to shorten the fermentation time of 1 day.(2)Study on the change of gas in the process of constant temperature fermentation,using the method of headspace solid-phase microextraction combined with gas chromatography and different methods of injection and polar organic reagents were used to treat the activated samples.The results showed that acetone,chloroform,carbon disulfide and other organic reagents on the fermented mandarin fish fermentation of gas detection was not good.The sample was treated by different injection methods and wefound that the blue polar organic reagents.(57318-u75um(PDMS / CAR)was good.By using a blue By using a blue flattened extraction for constant temperature fermentation process for 3-7 days,the total ion chromatogram showed that the gas composition in the fermental process is mainly some esters,olefins,ketones,alkanes and esters in the fermental process at 3 day(11 species)and6days(5 species)were higher.No ester compounds were detected at the day of 7;olefins did not change much during fermentation,mainly some hexadecene,dodecenes.Alkane compounds in the fermentation of the first three days is up to more than 20 kinds,in the first 4-6d in the relatively stable in 17,while in the fermentation7 d is reduced to a minimum,only 9.The ketones were mainly in the early stage of fermentation,and no ketone was detected after the 5th day,and other some compounds such as amine,alcohol and acid during the fermentation period,but the content of ketones was relatively less.