| Because of high nutritive value,special flavor,storage stability and portability,sea cucumber was very welcomed by consumers.However,sea cucumber was drying by traditional natural air-drying in most of the areas at present.In order to improve the level of drying sea cucumber,using Stichopus japonicus as the raw materials to meet the domestic and international market demand in this paper.Studies of this paper are based on drying dynamics of sea cucumber and the properties of dried sea cucumber at condition of hot air drying.It is the trend of modern drying techniques,and it will give a processing standard to sea cucumber industry.The effects of hot air drying method on the physical,chemical and sensory characteristics,as well as the changes in quality of dried sea cucumber after rehydration processing were investigated in this paper.The results showed that:1.The drying dynamics characteristics and drying model of sea cucumber were studied and constructed,respectively.The drying temperature influenced significantly on drying characteristics of se cucumber,the higher the temperature,the shorter the drying time is,the faster the drying efficiency is,and the down faster the moisture content is.It can be seen that the removal of moisture from the material is governed by diffusion phenomenon.The drying behaviors of the present study were best fitted with the Page model.The effective diffusivities for scallops varied from 1.84×10-9m2/s3.04×10-9m2/s,the diffusion constant D0 was 5.01×10-7m2/s,and the activation energy was found to be 14.23 k J/mol.Considering the quality of sea cucumber and the drying efficiency,the mathematical model of sea cucumber drying at different temperatures was established.2.The effect of different drying temperature on the sensory characteristics of sea cucumber was not significant.The bound water,immobile water and free water was detected in sea cucumber body wall before drying processing;however,only the bound water could be observed after processing.Strong significant effects of quality were observed on water distribution in dried sea cucumber.The change in water distribution during drying was implied that the bound water is the key role to drying-induced changes in sensory characteristics of sea cucumber.3.The changes in quality of sea cucumber after rehydration processing were also investigated.The higher temperature for drying processing of sea cucumber,the higher rehydration rate it was.The textural properties of dried sea cucumber after rehydration were compared.The shearing force,hardness and chewiness of rehydrated sea cucumber was increasing with the increased drying temperature,in which the maximal value reached at 50? and decreased after 60?.Meanwhile,combined with the results of scanning electron microscope,the muscle fiber of rehydrated sea cucumber?when the drying temperature was 30??aggregated and damaged significantly with the increased drying temperature;the worst aggregation phenomenon was obviously detected at 60?,which the fiber was aggregated into compaction.In summary,the proper drying temperature for sea cucumber was between 40 and 50?,and the drying duration was about 20-28 hours;in which,the optimal quality of dried sea cucumber after rehydration was easily obtained in the industrialization. |
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