| The clam meat is delicious, nutritious, with high food value and health effects. At present, the forms of clam products are various, but the study on quality control of the clam product are rarely reported. Instant clam is a kind of vacuum flexible packaging food with shell which is made by the processing of anti-pressure high-temperature sterilization. The flavor of instant clam changed worse with the increase of storage time. Therefore,instant clam can not won wide acceptance among the people. In order to provide the basis for the instant clam during storage, the research takes instant clam as raw materials, the quality and safety of the sample were studied during the storage in different temperature, and a mode which was used to predict the shelf life of instant clam were established. The main results are as follows:1. The nutritional value of instant clam both before and after storage were compared and analyzed. After ninty-day storage at 37℃, the content of water in the instant clam was declined from 78.25% to 71.10%; the content of protein was declined from 13.85% to 78.68%; the content of amino acids total was declined from 12.80 g/100g to 7.76 g/100g; the content of the fatty was declined from 1.77% to 1.69%, the contents of seven kinds of unsaturated fatty acids were declined from 126.97 ug/g to 117.04 ug/g; the content of ash was increased from 2.13% to 2.81%. The contents of water and protein were significantly different between before and after storage(P<0.05), and the contents of fatty and ash were no significant difference between before and after storage(P>0.05).2. Indicators used to appraise edible security in instant clam during the storage were analyzed. After three hundred and sixty-day storage at 25℃or 30℃, and after one hundred and eighty-day storage at 35℃or 40℃, the total number of colonies were≤1000cfu/g. That was showed the bacterial colony number in instant clam were maintained low condition during storage. Therefore, the process of sterilization is reasonable. The TVB-N was rising during the storage at 25, 30, 35, 40℃, and the TVB-N increased with the increase of storage time and temperature during the whole storage. TBA was on rise during the storage with the increase of storage time, but the effect of the temperature on TBA was only little.3. The sensory organ, color, texture, pH and microbiology indicators of instant clam during the storage were analyzed. The evaluation of sensory quality decreases with the increase of storage time and temperature, that was showed lower storage temperature is one of the operative methods to extend instant clam shelf-life. L decreased with the increase of storage time and temperature during the whole storage at 4, 25, 37℃; A firsty increased slightly and then decreased with the increase of storage time; B decreased with the increase of storage time, but the temperature affected TBA insignificantly. The spring and chewiness decreased with the increase of storage time and temperature; The hardness firstly increased, and then decreased with the increase of storage time during the whole storage at 4, 25, 37℃. Established the sensory quality and texture, color parameter regression model: y(Sensory score)=5.621×x1(Elasticity)-0.783×x2(b*)+6.439. The coefficient of determination of the model is 0.883. The pH was between 6.98~7.47during the storage at 4, 25, 37℃, which was acceptable. 34, 29, 20 aroma components were indentified in instant clam stored for 0, 45, 90 days respectively, of which 2-Pentene 5-(pentyloxy)-, amyl alcohol, Heptanol, 1-Octen-3-ol, Pentanal, heptanal, benzaldehyde, octanal, 2 - nonanone were found in all of the three samples and amyl alcohol, valeraldehyde, heptanal, benzaldehyde and octanal were the predominant compounds. The aromatic compoents in clam were mainly hydrocarbons, alcohols, aldehydes, ketones and esters. At the three storing stages, aldehydes were the most predominant aroma components; the relative contents of aldehydes exhibited a downward trend, and of alcohols and ketone an upward trend.4. Established kinetic models to predict instant clam shelf life:（？）It shows from the reliability assessment between predicted and observed shelf-life that relative error is within 10% calculated by the prediction model for the shelf-life of instant clam. Therefore, the kinetic models can show the relation between the quality changes and shelf life of instant clam in storage at the temperature of 25～40℃. |
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