Studying On The Change And Control Of The Processing And Storage Quality Of Dried Oysters

Oyster is a kind of delicious and nutritious seafood,which is deeply loved by people around the world.But fresh oysters contain high water,which means can not be preserved well.Drying become one of the most important processing methods.The oyster,in the process of drying and storing for a long time,is found that it is easy to reduce the quality,such as black and mildew.which seriously influence the sales of the dried oyster products.It is important to improve the deterioration of quality in the process of processing and storage.In order to achieve the quality of the dried oyster,this article aim to improve the drying process and adding additives in the production process.?1?Firstly,it has carried on the different temperature of hot air drying to the oyster experiment.And under the experimental conditions,an air thin layer drying kinetics model has been setted up.The Mathematical expressions is MR=exp[-?-0.168+0.0110T?t^0.7790].Then,considering the first phase of the drying temperature?X₁?,moisture transfer point?X₂?and second phase of the drying temperature?X₃?as three factors,the article optimize oyster hot air drying process through the three factors three levels response surface test.A combinatorial process model is established.Oyster dried sensory score and the dried rate of comprehensive score is Y index.The Mathematical expressions is Y=-30.0202+0.4738X₁-0.1290X₂+0.6803X₃-0.0025X₁²-0.0068X₃²-0.002X₁*X₃+0.0025X₂*X₃.It obtained by response surface software optimal drying conditions that the first stage drying?X₁=75??,moisture transfer point?X₂=25%?and dry in the second stage?X₃=44??.?2?Secondly,from mildew dried oysters isolated three mold strains,which have been appraised elementarily as 2 strains aspergillus and 1 strain penicillium.The mold.by comparing identified as aspergillus A is Aspergillus candidus,aspergillus B is Aspergillus niger,penicillium C is Penicillium lanosum.Bacteriostasis of Potassium sorbate,BHT and sodium lactate compound as anti-mould agent were taken by microorganisms to determine optimum concentration,having gotten to the best antibacterial combination is:0.1%sodium lactate+0.1%PS+0.008%BHT.?3?After adding compound additives to the oyster drying processing,taking storage test at different temperature.The shelf life models have got,by measuring the POV,AV and the total number of colonies.Through the model can predict the storage shelf life of dried oyster products under the condition of normal temperature.It can be kept for 235 days with the products quality is good.?4?Finally,The volatile components in the different stages of storage of dried oysters were analyzedbySimultaneousDistillationandSolventExtraction?SDE?andgas chromatography-mass spectrometry?GC-MS?method.Results show that the mainly Volatile substances at the beginning of the storage dried oyster are alkane and aldehydes.such as heptanal,caprylic aldehyde,dextral limonene,camphene,eucalyptus leaf alcohol,2-nonyl ketone,jiale musk have a greater influence on the flavor of dried oysters,which work together to give early storage dried oysters with special pleasant shellfish meat sweet fragrance;The main volatile substances in the medium storage dried oyster are C₁₃^C₁₈ aldehyde and olefin.like18aldehyde,palm aldehyde,dextral terpene diene and myrcene,cyclopentadiene,formic acid vinyl ester,etc.,the fragrance of these compounds is not strong,some even imperceptible;In the late storage the main volatile substances are some complex quinones,sulfur and nitrogen compounds.like 2-mercapto-3-pyridine alcohol,12-12 alkyl ether,twelve ester p-toluene sulfonic acid,stearyl hydrazide,2-4-methoxy pyridine bromide-phthalate butyl acetate,acetic acid,etc,which compounds have unpleasant sour and fat oxidative rancidity.