Study On Drying Technology Of Antarctic Krill Powder

Antarctic krill is rich in biological resources and has high nutritional value.Antarctic krill powder is the main processed product of Antarctic krill,and the drying process is a key factor that restricts the quality and cost of shrimp powder.At present,the research on the processing of krill powder at home and abroad mainly focuses on quality evaluation,storage conditions,etc.There are few studies on the drying process and parameter optimization.Therefore,the research on the drying process of Antarctic krill powder is of great practical significance for the processing of Antarctic krill.In this study,the frozen Antarctic krill was used as the experimental raw material.The pretreatment method was flow hydrolysis,steam cooking for 3 min,study the pre-drying treatment(crushing process),the effect on the drying characteristics and the quality of Antarctic krill powder,and determine the suitable Antarctic krill crushing process.On this basis,the experiments of hot air,microwave,flash and combined drying of Antarctic krill powder were carried out to explore the optimal drying process of Antarctic krill powder.The specific research content and results were as follows:(1)Effect of pre-drying treatment(crushing process)on drying characteristics and quality of Antarctic krill powder.The experiments on the particle size,crushing mode and crushing time of Antarctic krill were carried out.The effects of the crushing process on the drying characteristics and the quality of Antarctic krill powder were analyzed.The suitable crushing process of Antarctic krill was obtained.The results showed that chopping and crushing for 90 s was the best pre-drying treatment for Antarctic krill powder when the rotation speed was 200 r/min.The drying efficiency of Antarctic krill powder was increased by 37%,the particle size distribution of Antarctic kril was less than 2 mm accounted for 40%,2 ~ 4 mm accounted for 14%,4 ~ 6 mm accounted for 14%,6 ~ 8 mm accounted for 7%,and 8 ~ 12.5 mm accounted for 25%.(2)The hot air,microwave and flash drying experiments on Antarctic krill powder were carried out and evaluated by comprehensive quantitative evaluation,and the optimal process parameters were obtained.The results showed that when the Antarctic krill moisture content was 10% ~ 50%,the drying temperature was 75?,the hot airdrying process was optimal;When the moisture content of Antarctic krill was 10% ~40% and the microwave power was 450 w,the microwave drying process was the best.When the Antarctic krill moisture content was 50% ~ 80%,the inlet air temperature was150?,outlet air temperature was 95?,flash drying process was the best.Flash drying was suitable for the drying of Antarctic krill with high moisture content,and hot air and microwave were suitable for the drying of Antarctic krill with low moisture content.On the basis of this experiment,the study was carried out on the flash hot air combined drying and flash microwave combined drying process of Antarctic krill.The results showed that compared with single drying,the shrimp powder prepared by combined drying had higher quality,shorter time and lower energy consumption.By comparing the flash hot air combined drying and flash microwave combined drying,it was found that the shrimp powder prepared by flash hot air had high quality,but a longer drying time and higher drying energy consumption.The flash microwave drying time was short,and the energy consumption was low,but the quality was slightly lower.(3)Comprehensive evaluation of the drying process of Antarctic krill powder.The results showed that the best Antarctic krill powder drying process was flash microwave combined drying.When the inlet air temperature was 150?,the outlet air temperature was 95?,the moisture content of the flash-dried Antarctic krill was 40%,and then when the power was 450 w,the moisture content of the microwave-dried Antarctic krill was 10%.The drying energy consumption was 2.612 kW·h/kg and the drying time was8 min.The content of astaxanthin in shrimp powder was 310.69 ug/g,the fat content was 20.13%,the water-soluble protein content was 25.31%,and the salt-soluble protein content was 34.09%.(4)Hot air drying of Antarctic krill powder had high energy consumption and long time,but the quality of krill powder was the best.Microwave drying of Antarctic krill powder had the lowest energy consumption,but longer drying time and the worst quality.Flash drying of Antarctic krill powder had the shortest time,higher quality and higher energy consumption.Combined flash drying and microwave drying can reduce drying energy consumption,effectively retain the content of nutrients in shrimp powder,and make up for poor quality of shrimp powder in microwave drying and high energy consumption in flash drying.To sum up,the best pre-drying treatment method of the Antarctic krill was chopping broken 90 s(chopping machine,200 r/min),the best drying process was theflash microwave drying(in the inlet air temperature was 150?,under the condition of outlet air temperature was 95?,flash drying Antarctic krill moisture content to 40%,and then under the condition of 450 w,microwave drying Antarctic krill moisture content to 10%).