Study On The Quality Changes Of Trituberlatus At Low Temperature Conditions

Taking trituberculatus as the study object,the quality changes of trituberculatus under cold storage at 0℃ were studied by measuring the sensory evaluation and the four chemical indicators,including the value of volatile nitrogen(TVB-N),PH value,K value and TBA value.The experimental result showed that storage period of trituberculatus was 8 days at 0℃ through sensory evaluation.TVB-N value could not reflect the quality change of trituberculatus properly,but PH value,K value and TBA value were good indicator to evaluate the quality changes,which could act as an assistant index to test the edible quality of trituberculatus.When the pH value was higher than 8.0,K value reached 40%,and TBA value was 10 mg/100 g,the trituberculatus quality was deteriorated and inedible.The quality of died trituberculatus with different death time(0 h,2 h,4 h,6 h)was evaluated under the cold storage at 0℃ by testing three physical and chemical indicators,including K value,pH value and TBA value to explore its availability.The experimental results showed that the storage time of trituberculatus was 8 days,5 days and 2 days after they died for 0 hour,2 hours and and 4 hours respectively.They still had commodity value to be used for further processing,but there wasn’t any storage value if they died for 4 hours.In the study of the influence for trituberculatus caused by the ice glazing process during cold storage,the control group and the ice glazing group were created.Trituberculatus in two groups were stored at-18℃.We measured and analylized TVB-N value,pH value,K value and TBA value of the samples every 15 days.The results showed that in the control group,the storage period for trituberculatus was 120 days and TVB-N value,pH value,K value and TBA value all exceeded the critical point,indicating no commodity value,and that in the ice glazing group,the the storage period of trituberculatus was significantly prolonged to about 180 days.We could see that compared with trituberculatus under freezing storage directly,ice glazing process could delay its quality deterioration and prolonged the storage period.By measuring and analyzing the free amino acids in different parts of Portunus trituberculatus,we could see that there were significance differences for female and male trituberculatus in the total amount of free amino acids,the total amount of essential amino acids,the total amount of amino acids and the total amount of amino acids and the content of free amino acids in different parts of female trituberculatus were higher than that in male trituberculatus.