| Active functional components are present in most plant cells,can regulate the function of the human body by activating the activity of some enzymes or other ways,such as enhancing immunity,preventing and treating diseases.With the development of the food industry,substances are extracted to enhance the functionality of food products.The traditional method of organic solvent extraction has many deficiencies,for example,high energy consumption,long extraction time,cumbersome process,low yield.Some external mechanical assistances to enhance wall breaking and increase intracellular Mass transfer processing modern extraction methods as well as shorten the extraction time and improve its extraction rate,such as microwave-assisted extraction,ultrasonic-assisted extraction and high-voltage pulsed electric field-assisted extraction,Among them,the technology of high-voltage pulsed electric field extraction is favored by many people in the industry because of its fast extraction rate and good extraction effect at or near room temperature.However,the equipment of high-voltage pulsed electric field has a relatively slow development due to its high cost of high-voltage pulsed power supply,difficulty in constructing a control system,and the need for special processing of the processing device.At present,there is no industrial extraction equipment for the high-voltage pulsed electric field in China,this paper developed a pilot-scale high-voltage pulsed electric field equipment with a processing capacity of 1 t/h,which is amplified for the processing capacity and power of laboratory-scale equipment.Then,the equipment was applied to extract the anthocyanins from the grapevine,and the extraction effect of the equipment was explored.The main research contents and results were as follows:1)A power of high-voltage pulse with generates exponentially decaying waves was designed with a maximum output voltage of 32 k V and a frequency between 1 Hz and 5 Hz.In addition,a pneumatic reciprocating spark gap switch was designed.The switch was designed using a solenoid valve to drive the forward motion of the two small ball electrodes.And then the analog simulation of the electric field distribution between the two small balls at different intervals was operated using the COMSOL Multiphysics software.The forward motion of the minimum distance between the two balls was confirmed at 1 mm.2)A high-voltage pulsed electric field processing device was designed,which included feeding device,conveying device,discharging device and control box,etc..And the structure and operation process of each device were analyzed.Besides,the traditional flat-type static processing chamber was optimized so that the proportion of uneven volume in the processing chamber was reduced from 4.3% to 1.2%,which caused by the adding metal conductors in the gap between the high-voltage electrode plate and the inner wall of the processing frame to improve the uniformity of electric field distribution in the processing chamber.3)Comparison the extraction influence of the content of total phenols,flavonoids and anthocyanins in amur grape pulp by the high-voltage pulse electric field technology of the equipment,heat extraction method,and ultrasonic extraction technology.The results showed that the three extraction methods are conducive to the dissolution of polyphenols from amur grape.The contents of total phenol,flavonoids,and anthocyanins using the extraction method of pulsed electric field compared with untreated grape pulp were increased by12.2%?11.1%?and 11.3%,respectively.4)The effect of the parameters of the equipment on the content of anthocyanins in grape pulp was explored,and three sets of experimental programs were developed.The first scheme was to control the input energy of the equipment and explore the effect of applied voltage and pulse number on the extraction effect.An upward trend of the content of anthocyanin in grape pulp was showed with the increase of applied voltage,which indicated that the influence degree of the applied voltage was higher than that of the pulse number.The second scheme was researched about the extraction effect at different frequencies,and the results showed that the anthocyanin content had a downward trend when the frequency from 1 Hz to 5 Hz;the third one was to control the strength of input field,and explored the extraction effect of anthocyaninin amur grape under three conditions of 5 k V/5 cm,10 k V/10 cm,and 15 k V/15 cm with the contents of 344.25±1.61 mg/L,346.76±1.10 mg/L,353.11±1.32 mg/L,respectively.It indicated that the treatment effect of 15 k V/15 cm was the best one.5)The equipment was applied to compare the extraction effect of the anthocyanin content in grape pulp on the condition of 30 k V/10 cm with the experimental scale equipment under the condition of 15 k V/5 cm.The results showed that the processing capacity was about 20 times the experimental scale equipment.And under the same strength of the input field,its extraction effect was slightly better than that of experimental scale equipment.It showed that the equipment was satisfied with the requirement of the pilot test,and the processing capacity and power were amplified successfully for the experimental scale equipment. |
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