Production Of Gingerol By Enzyme Assisted Ethanol Extraction And Comprehensive Use Of Ginger

China is a major producer of ginger in the world.In 2015,the annual output of ginger in China reached 10 million tons,accounting for about 45%of the world’s total output.Gingerol is a general name of spicy ingredients in ginger,and it is an important product from ginger deep processing.After gingerol extraction,there are large amounts of solid residues,which contains rich polysaccharides,cellulose and other substances.It is significant for promoting the comprehensive utilization of ginger and improving economic benefits through high effective utilization of the residues to produce value-added products.It is a common method to extract gingerol by ethanol and other organic solvents.In the process of extracting ginger with organic solvent,cellulase could be used to destroy the structure of plant cell wall.Published literatures about extraction of gingerol by enzyme assisted organic solvent technology mostly focused on the optimization of enzymatic treatment conditions,for example,treatment time,temperature,pH etc.Little research is reported on the effect of enzyme types and enzyme system on yield of gingerol.Since the degrading effect of enzymes on substrates is closely related to the types and systems of enzymes,it is of great significance to evaluate the effects of different enzymes for reducing the cost of enzymes used in processing.In addition,there are few studies on the comprehensive utilization of the solid residue from gingerol extraction process.In view of these problems,in this study,enzyme assisted ethanol extraction of gingerol is researched using different source enzymes and enzyme mixtures,and the feasibility of producing dietary fiber and fermentable sugar by using the ginger residues as feedstock are discussed,which will be valuable for the further comprehensive utilization of ginger.The main work and results of this paper are as follows:(1)Based on the analysis of the main chemical components of gingerol,a method of assessing the content of gingerol is established by measuring the light absorption at 280 nm using UV-vis spectrophotometer.Compared with the common methods,it is simple,rapid and convenient especially to the determination of on of large mumber of samples in the research.The conditions of ethanol extracting gingerol are optimized,and found that,when the ginger powder is 60 mu,ethanol concentration is 75%,the solid-liquid ratio of 1:20,extraction temperature and time is 50℃ and 30 min respectively,the gingerol extraction yield reach 1.70%(on dry ginger weight),which is a high level compared to the data reported in literatrues.(2)Five crude cellulase enzymes are prepared by liquid fermentation using five cellulase-producing strains with different protein compositions,and their effects on the extraction yield of gingerol are studied.The results show that different improvement effects on subsequent ethanol extraction are found by treatment with the different cellulase,whether adding the same amount of protein or the same amount of enzyme activity.By comparing the difference on various enzymes activities and the inhibition of gingerol on the CMCase activity,it is speculated that different effect on improvement of the gingerol extraction yield may be because,there are different amounts of other enzymes such as pectinase,xylanase,amylase and fliter Paperase in hydrolysis system under the same amounts of addition of CMCase activity or protein,in which,pectinase has a very significant effect on the yield of gingerol extraction;and the inhibition of gingerol on enzyme activity of different crude enzymes is different.It is shown that the improvement effects of the two crude cellulases from P.oxalicum strain Re-6 and P.oxalicum strain Re-7 respectively are better than that of other crude cellulase.Further,the effect of mixtures of cellulase and pectinase on the extraction yield of gingerol is also studied,and showed that the treatment with mixed enzyme could significantly increase the extraction yield of gingerol,and also,the addition of pectinase could reduce cellulase dosage.It is found that the treatment with amylase promotes the extraction yield of gingerol even if under a short enzyme treatment time.(3)Macroporous resin is used to purify the extracted gingerols,and the resin type and purification process are preliminarily researched.The results show that suitable process for purification of gingerol is that,the extracted gingerol solution is separated using HPD-950 resin,and eluted with 60%ethanol solution at the flow rate of 1.0 mL/min.(4)Based on the antioxidant properties of gingerol,effects of the purified gingerols on inhibiting the oxidative rancidity of edible oils are preliminarily investigated.It is found that the inhibition effect of gingerol is similar to that of several antioxidants in the market.The feasibility of comprehensive utilization of ginger residue is discussed.Dietary fiber is extracted from the ginger residues and its characteristics are evaluated.The feasibility of glucose production by enzymatic hydrolysis of the ginger residues using cellulase is assessed,which provide a reference for high value-added products by enzyme hydrolysis fermentation process using the residues as feedstock.