Studys On Combined Superheated Steam And Vacuum Drying Of Laminaria Japonica Aresch

Laminaria Japonica Aresch,which grows in the low-temperature seawater,is a large marine brown purple plant and also a high nutritional and medicinal vegetables.Due to large production,high moisture content and great difficulty of storage and preservation,dehydration has played an important role in Laminaria Japonica Aresch'processing.Superheated steam drying(SSD)technology was applied to Laminaria Japonica Aresch ' drying in this paper.Effects of drying parameters on main quality of Laminaria Japonica Aresch were investigated and the optimal parameters of SSD were also determined.However,single superheated steam drying(SSD)does not meet the quality requirements of dried kelp.So combined superheated steam and vacuum drying(SSVD)is vital to be applied to Laminaria Japonica Aresch' drying in this paper.Effects of drying parameters on main quality of Laminaria Japonica Aresch were investigated and the optimal parameters of SSVD were also determined.In addition,economy of SSVD was analysed in the paper.1?Effect of SSD parameters on Laminaria Japonica AreschShrinkage,Rehydration,polysaccharide content and the change of color as evaluation,the effect of SSD steam temperature,steam velocity and Laminaria Japonica Aresch thickness on the quality of Laminaria Japonica Aresch were analysed.Taking dehydration quality of Laminaria Japonica Aresch and energy consumption into account,the best ranges were that the steam temperature was 110?120 ?,the thickness was 5?9 mm and the steam velocity was 1.5?2.1m/s?2·SSD technology optimization of Laminaria Japonica AreschThe effect of steam temperature,steam velocity and thickness on shrinkage and polysaccharide content were studied by response surface methodology(RSM).Regression models of shrinkage and polysaccharide content were established.The optimal parameters were obtained by analysis both of single factors and double factors response surface analysis.The results showed that the actual value fitted well with the model predictive value.It could be used to predict the change of shrinkage and polysaccharide content.The two regression modes respectively were:Y1=91.54-0.73X1+0.81X3+1.15X12+0.83X22+0.78X32;Y2=4.63+0.39X1-0.56X3-0.90X12-0.64X22;At last,the optimal parameters were that the steam temperature was 116.34?,material thickness was 5,54 mm and steam velocity was 1.84 m/s.3?Effect of SSVD parameters on Laminaria Japonica AreschShrinkage,rehydration,polysaccharide and protein content as evaluation,the effect of SSVD conversion time,temperature and vacuum on the quality of Laminaria Japonica Aresch were analysed.Taking dehydration quality of Laminaria Japonica Aresch and energy consumption into account,the best ranges were that the conversion time was 60?90min,the temperature was 65?75? and the vacuum was 0.05-0.07MPa.4?SSVD technology optimization of Laminaria Japomica AreshThe effect of conversion time,temperature and vacuum on rehydration and polysaccharide and protein content were studied by response surface methodology(RSM).Regression models of rehydration,polysaccharide and protein content were established.The optimal parameters were obtained by analysis both of single factors and double factors response surface analysis.The results showed that the actual value fitted well with the model predictive value.It could be used to predict the change of polysaccharide and protein content?rehydration and the three regression modes respectively were:Y1=5.11+0.46X3-1.16X12-0.98X22-0.67X32;Y2=0.23-0.037X1-0.042X3-0.027X1-2-0.050X22-0.088X32;Y3=22.47-0.36X1+1.09X3-2.85X12-2.21X22-1.12X32;At last,the optimal parameters were that the conversion time was 73.46min,the temperature was 69.89? and the vacuum was 0.061Pa.5?Comparison of combined Superheated Steam and Vacuum Drying(SSVD)and Hot Air Drying(AD)on energy utilizationCompared with combined superheated steam and vacuum drying and hot air drying in the aspects of heat transfer capacity of drying medium and the energy took away by exhaust and made an economic analysis of both.The results showed that efficiency of drying was improved and drying time was reduced by SSVD.The energy took away by SSVD was less than AD and Energy consumption of SSVD was far less than that of AD.The temperature of exhaust of SSVD was high,so it could be recovered and the energy recovery was up to 80.44%.The energy needed of hot air drying was 6.55 times as much as combined superheated steam and vacuum drying.