Study On The Quality Of Ready-to-eat Sea Cucumber During Storage And Shelf Life Prediction

During recent years,with the continuous improvement of the sea cucumber nutritional value and edible convenience demand,ready-to-eat sea cucumber products are favored by more and more people.But the reports about standard specification of the ready-to-eat sea cucumber products quality is relatively little,this experiment aims to provide reference basis for the establishment of product standards by researching the ready-to-eat sea cucumber index change of sensory,physicochemical and microbiological quality during storage.In sensory analysis,we considered smell,organization structure,springiness,surface viscosity of ready-to-eat sea cucumber as the evaluation index,taking 3 points to make the sensory evaluation of sample,which stored at different temperature.At the same time,using the TPA texture experiments to complete the sensory experiment,and acquiring the TPA parameters of sensory evaluation test point(hardness,springiness,chewiness,etc),in order to make the sensory index has the value significance.For physical and chemical analysis,semi-micro Kjeldahl method was used to determine TVBN in this experiment mainly.And at the same time,pH instrument was used to measure the pH changes of ready-to-eat sea cucumber products during storage.For microbiological analysis,firstly,the total viable count and E.coli count of ready-to-eat sea cucumber products under different storage temperatures were measured,combined traditional isolation and culture method and 16S rDNA flora analysis method,and separated,purified and identified the main spoilage strains of sea cucumber products.Then applied the modified Gompertz equation to describe the spoilage microorganism growth curve,the Belehradek equation to describe the effect of temperature on the maximum specific growth rate(?max)and the delay time(Lag),and then constructed the shelf life prediction model.The results showed that,(a)with the increase of storage time,the quality of the products reduced gradually,when the sensory acceptance limit,the smell,surface viscosity and hardness of the products change significantly,at this moment,the TPA test results of ready-to-eat sea cucumber for the hardness was(1232.187±149.530)g,springiness was 0.824±0.059,adhesiveness was 0.744±0.009,chewiness was 880.003±90.641;the TPA test results of soaked sea cucumber for the hardness was(896.130±173.281)g,springiness was 0.750±0.041,adhesiveness was 0.653±0.078,chewiness was 699.481±86.838;(b)the trend of TVBN was positively correlated with storage time,and the higher temperature,the faster it changed,when the sensory acceptance limit,the TVBN test results of ready-to-eat sea cucumber was(9.19±1.450)mg/100g.The soaked sea cucumber TVBN change relatively quickly,when the sensory acceptance limit,the TVBN test results of soaked sea cucumber was(25.53±4.413)mg/100g;the sea cucumber polysaccharide is on the decline with the increase of storage time,when the sensory acceptance limit,the polysaccharide content of ready-to-eat sea cucumber and soaked sea cucumber was(1.191±0.030)g/100g and(1.204±0.050)g/100g respectively.pH has no significant changes during storage,only fluctuate between 6.3?7.4;(c)with the increase of storage time,the total viable count(TVC)increased gradually,and the higher temperature,the faster the rate of growth,when reaching the sensory limit,the TVC of ready-to-eat sea cucumber was(5.23±0.1146)logcfu/g,the TVC of soaked sea cucumber was(4.39±0.067)logcfu/g;(d)through the NCBI for sequencing shows,there were mainly eight strains during storage,respectively,Bacillus,Psychrobacter,Rahnella sp,Exiguobacterium and Acinetobacter,early in the storage mainly Bacillus based,and when it reached the end point of corruption are mainly Rahnella sp,Acinetobacter,and Psychrobacter.(e)the use of the modified Gompertz equation can be well fitted the growth of spoilage microorganisms curve,R2 between 0.9932 to 0.9977.Belehradek equation also showed good linear relationship on microbial dynamics.Shelf life prediction model of 3? and 8?refrigerated shelf life value was 128d and 55d respectively,and the measured value was respectively 110d and 50d.