Effect Of Desalination And Drying Process On The Quality Of Dried Apostichopus Japonicus

Sea cucumber which has abundant nutrients and physiological active substances has a significant status and broad development perspective in China fishery.In recent years,the need of the sea cucumber was driven by the life level of ascension,but the market is a place good and bad mixed with sea cucumber.So,the processing methods of high quality sea cucumber were needed.The sea cucumber with autolytic enzyme,was difficult to preserve.To this problem,the processing technologies of sea cucumber were needed,but different processing ways will generate different on the quality of sea cucumber.In order to meet the market demand for sea cucumber,the processing technologies were studied by screening and optimizing to improve the efficiency and reduce the nutrient loss and destruction of the organizational structure.The processing technologies of sea cucumber mainly have the cooking,salting,desalination,drying and rehydration.At present,the research of the desiccant and cold air drying processings is relatively vacant.So the research of the above processing ways is very important to improve processing efficiency and quality of sea cucumber in sea cucumber industrial production.This paper studied the desalination way of Apostichopus japonicus,cold air drying process and comparison of the drying process.It was expected to offer a theoretical and data support for the industrial production of sea cucumber.1.In this paper,desalination methods(water immersion,oscillation,vacuum reverse infiltration and ultrasound)were used to reduce the salt of Apostichopus japonicus,the changes of quality with different desalting methods were mainly investigated based on desalination rate,the protein and total sugar loss and sensory characteristics.The experiment results showed that these ways of desalination,oscillation,vacuum reverse infiltration and ultrasonic treatment,could improve the desalting rate and also reduce the rate of protein and total sugar losses when salt content was 11%.Vacuum reverse infiltration requires 2 h,the rates of protein losses and total sugar losses respectively were124 mg/g and 7.45 mg/g.With the same conditions,the order of the total protein losses was,ultrasonic treatment> clear water immersion>oscillation> vacuum reverse infiltration.The order of the total sugar losses was,clear water immersion>ultrasonic treatment>oscillation> vacuum reverse infiltration.Vacuum reverse infiltration has the least influence on the sensory characteristics in the short time of desalination.It is a particularly efficient desalting method that can maintain good quality of Apostichopus japonicus.2.To study the effect of cold air drying process on the quality of Apostichopus japonicus,the drying rate,heat shrinkage,rehydration dry weight rate,sensory characteristics and textural characteristics were determined at the different desalination time,drying temperatures and the speed of cold air.Meanwhile the optimized technology of the cold air drying was studied.The results showed that,the influence of the speed of cold air on the quality of Apostichopus japonicus is close to the desalination time,the drying temperatures have less influence.The speed of cold air 1.5-2.0 m/s,the desalination time 4-5 h and air temperature about 18-20 ?,is the suitable air drying effect of Apostichopus japonicus.The Apostichopus japonicas that were dried by cold air have high quality and the drying process have a strong maneuverability.Based on the sensory characteristics and drying rate of Apostichopus japonicus,the comprehensive score obtained by the weighted method was used as the index to study the cold air drying process.The desalination time,drying temperature and cold wind speed were selected as independent variables.The comprehensive score was the response value,the effects of the independent variables and their interactions on the comprehensive score of the products were studied by using the Box-Benhnken center combination design principle and the response surface analysis method.The optimal drying conditions were determined as desalination time of 4.2 h,drying temperature of 19 ?,and cold air velocity of 1.7 m / s.The prediction model of quadratic polynomial regression equation was simulated.Under this condition,the comprehensive value of the product is 0.77.The compared with the theoretical prediction value of 0.78,the relative error is about 1.6%.It can indicate that the equation obtained by the response surface optimization has a guiding significance for the cold air drying process.3.In order to explore the effect of different drying processes on the quality of Apostichopus japonicus,.Four drying methods(cold-air drying(CAD),vacuum freeze drying process(FD),hot-air drying process(HAD)and vacuum microwave drying process(VMD))were used to dry Apostichopus japonicus,the protein and total sugar loss,heat shrinkage,rehydration dry weight rate,sensory characteristics and textural characteristics were measured after drying.The results indicated that in the field of nutrition conservation,FD and CAD were better than HAD and VMD;in the terms of heat shrinkage radio,HAD>VMD>CAD>FD,CAD and FD have Less difference;In the terms of the rehydration rate and sensory characteristics,CAD ? FD ?HAD>VMD.In the terms of textural characteristics,CAD and FD had better effect than HAD and VMD.So CAD were more practicality in the industrial production.