Research Of Tuna Sashimi Main Processing And Transpotration Technology

Tuna owns tender and delicious fleshy, rich nutrition, which is usually eaten in theway of sashimi, therefore the nutritional quality, especially the color, is closely related tothawing methods. Aimed at improving the added value of tuna and technology conditions,this paper used the yellow-fin tuna in-55℃cold storage for raw materials, with thetraditional and new thawing technology to ascertain the factors that influence its quality(including the color value, high iron muscle protein content of the red, pH value, K value,microorganism quantity, smell, etc.). We analyzed the physical and chemical indexes andsensory evaluation under different thawing time, temperature and heat-transfer medium toidentify the best thawing craft. We combined the final optimum processing conditions withthe modern food processing technology by detecting and analyzing the influence to thecolor of processing conditions, especially the temperature and time. Through transportingtuna sashimi after processing, exploring the influence to the last quality of tuna sashimi indifferent transport conditions, assisting the electronic nose technology to distinguish thesmell test of the final products, we can get the whole quality information of tuna. Besides,tuna meat under different transport conditions will be identified and classified. The mainresults obtained by the paper are as follows:Thawing: The thawing method with-55℃â†'-25℃low-temperature in1h andultrasonic thawing within0.5h could keep the color and freshness best. Among them, wedetected various indexes in-55℃â†'-25℃l ow temperatureafter1h, the color value was19.37, high iron muscle protein content of red was19.91%, pH6.45, K value was14.61%,the microbe quantity was118CFU/g, the electronic nose variance99.322%, sensory scorewas12; Ultrasonic thawing after0.5h, the color value was19.91, high iron muscle proteincontent of red was19.76%, pH6.53, K value was13.16%, the microbe quantity was91CFU/g, the electronic nose variance99.625%, sensory score was12. Through theexperiment we can see, tuna under these two thawing methods can achieve the raw foodstandards.Processing: Pure water or the cooling water after boiling, stainless steel cutting toolsare the basic requirements. When we processed500g fish, we had better finished the workin15min or less than20min, and the processing temperature is maintained at4℃andeven lower. At this time the measurement of color value was20.58, the microbe quantitywas82CFU/g, sensory scoring: color90, quality90, smell90, taste85, flavour85. Theprocessing time and temperature are the important factors for tuna sashimi quality, soensuring the rapid operation and appropriate environmental temperature is the key to gain the high quality tuna sashimi after processing.Simulating transportation: The-55℃ultra-low temperature simulating transportationhas obvious advantages than other conditions. In this condition, the physical and chemicalindexes and the sensory evaluation can both maintain in fresh level. The color value was21.31, high iron muscle protein content of red was18.75%, pH6.73, K value was11.06%,the microbe quantity was36CFU/g, the electronic nose variance99.612%, the sensoryscore was15. So the ultralow temperature can keep the freshness of tuna.