| Scallops with a high nutritional and medicinal value, rich in nutrients and biological active ingredient, is one of the marine food as drug, food and nourishment.Because of its seasonal and regional characteristics, frozen, dried, and instant scallops are the main processed forms of this species. Due to their high moisture content, vacuum-packaged instant scallops are perishable during storage. In order to accurately predict the shelf life according to the storage environment to meet the industry and storage demand, in this paper, using the bay scallops as the raw materials, a comprehensive nutritional analysis and a nutritional evaluation were investigated. Vacuum-packaged instant scallops stored at 20, 25, 30, 35 and 40℃were used in the current study. Physical and chemical properties, microbiological composition and sensory evaluation were ascertained during storage. The first order kinetic equation between TVB-N and storage time (t), and Arrhenius kinetic equation between rate constant of TVB-N (k) and storage temperature (T) were established to predict quality change of instant scallop and shelf life during storage for any given temperature-time profile. Amino acids composition and volatile compounds in instant scallops of early and late storage were determined. The results showed that:1 In this paper,general nutrients(moisture,crude ash,crude protein and crude fat),amino acids,fatty acids,mineral elements as well as vitamines in edible part of Argopectens irradias were investigated.The examination results showed that the content of moisture,crude ash,crude protein and crude fat in fresh edible part of Argopectens irradias were 81.27%,1.45%,12.70% and 2.21%,respectively.Eighteen common amino acids were found in the edible part of Argopectens irradias.In dry sample,the total content of amino acids(TAA)was 65.43%;the contents of essential amino acids(EAA)was 19.95%,and the ratio of EAA to TAA(WEAA/WTAA) and to nonessential amino acids (WEAA/WNEAA) were 30.49% and 51.70%, respectively;the content of flavor amino acids(FAA)was 31.33% and the ratio of FAA to TAA(WFAA/WTAA)was 47.88%.The constitutional rate of the essential amino acids did not meet the Food and Agriculture Organization of the United Nations/World Health Organization ( FAO/WHO )Standard.According to nutrition evaluation in amino acids score(AAS)and nutrition evaluation in chemical score(CS), the first limited amino acid was Lys and the second limited amino acid were Tyr+Phe. The essential amino acids index(EAAI)was 55.61. The ratio of PUFA to total fatty acids content was 40.99% and the ratio of EPA+DHA to total fatty acids content was totally 30.15%;the content ofω-3PUFA was rich,which was much higher thanω-6PUFA.The composition of mineral elements in edible part which was rich in Fe and Se was reasonable and the contents of VE and VB5 in vitamins were rich.2 Vacuum-packaged instant scallops stored at 20, 25, 30, 35, and 40℃were studied in the current study. pH, moisture, water activity (Aw), color, hardness, springiness, chewiness, gumminess, total volatile base nitrogen (TVB-N), thiobarbituric acid (TBA), microbiological composition and sensory evaluation were investigated during storage. The examination results showed that an increase in storage temperature resulted in the faster decrease in the quality of instant scallop and a shorter shelf life. The shelf lives of instant scallops stored at 20, 25, 30, 35, and 40℃were 96, 78, 60, 42, and 32 days, respectively.3 The first order kinetic equation between TVB-N and storage time (t) is and Arrhenius kinetic equation between rate constant of TVB-N (k) and storage temperature (T) is .4 Amino acids composition in instant scallops of early and late storage was determined. The results showed that 18 kinds of amino acids were found in instant scallop; and main components were as follows: 7 kinds of essential amino acids, 2 kinds of conditional essential amino acids, 2 kinds of half essential amino acids and 7 kinds of none essential amino acids. During the storage, almost all the amino acids decreased, while Phe, Lys and Tyr increased. Especially for Lys, it increased from 1.38mg/g to 3.65mg/g.5 Volatile compounds in instant scallops of early and late storage were determined. Results indicated that 9 descriptive words (sweet, boiled corn, sea breeze, sour, irritate, dried fish, boiled egg, Kamaboko, boiled scallop ) were used to describe the aroma property of instant scallops by quantitative descriptive analysis (QDA); Totally 44 and 55 aromatic components were found in instant scallops of early and late storage respectively; and main components were as follows: sulfur- containing compounds, aromatic hydrocarbons, furan,pyrazine and other aromatic components. Dimethyl sulfide was the characteristic aromatic component of instant scallops; Vacuum-packaged instant scallops have gone bad after 3 months’storage. Trimethyl-pyrazine and 2,4,6-trimethyl- decane were determined to come the off-flavors by Maillard. |
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