Preliminary Studies On Control Measures Of Methanol Content In Traditional Chinese Jujube Brandy

Traditional Chinese Jujube Brandy is brewed with substandard Jujube, which is most produced infamily wine distilleries with a process of crushing, wetting, straw mixing, naturally fermentation in tankand distilling by steaming. The obtained Traditional Chinese Jujube Brandy shows a high ethanolcontent, from40%to80%v/v without any blending. Traditional Chinese Jujube Brandy has yellowcolor, moderate, pleasant Jujube and soft sweet flavor, more important retains the Jujube’s nutritionalvalue and medicinal value, is a typical health wine which can easily and is fully absorbed by humanbody.The Traditional Chinese Jujube Brandy has a history of thousands years in China, but itsmanufacture and market is restricted in a large extent reason of high methanol content expect alarge-scale industrial production. Methanol quota carries out by GB2757-2012National Food SafetyStandard-Distilled Spirits and Liquor Preparation Hygiene Standards (Standardization Administrationof the People’s Republic of China，SAC). While GB2757-2012(SAC) requires the maximum limit ofmethanol content is2.00g/L in100%v/v ethanol (with raw materials of dry sweet potato andsubstitutes). Therefore, research in methanol formation mechanism and proposing control measures isimportant, and could provide a theoretical basis for large-scale industrial production.In order to study the effects of Pectinase treatment and Steam Boiling Treatment and DifferentFermentation conditions on Methanol content and Ethanol content in Traditional Chinese Jujube Brandy,the Cangzhou Golden Jujube solid-state fermentation which imitated the production technology of theTraditional Chinese Jujube Brandy was optimized. The following results were obtained:(1) A novel method of simultaneous determination of methanol and ethanol content in TraditionalChinese Jujube Brandy was established，and24samples were analyzed by the method.Direct injection of the Traditional Chinese Jujube Brandy samples into a30m TG-35MSsemi-polar column with a flame ionizing detector has been proven useful to detect methanol and ethanolcontent in a very short time. The regression between the peak area and the concentration value ofmethanol and ethanol found for peak area (y) to concentration value (x) werey=257.27x+3.5596(r2=0.9995) for methanol and y=239.19x+510.32(r2=0.9969) for ethanol, both fitted aliner relationship well. The linear ranges of the calibration curve for methanol and ethanol were bothwide, range from31.25μg/100mL to3.20g/100mL for methanol and1.25%v/v to80%v/v for ethanol.Standard addition of methanol and ethanol led to excellent recoveries of101.8%and101.3%, respectively. With this method, pre-treatment of sample is no longer required and less than19.10min istaken for one single analysis from direct injection of original samples to obtaining data. Using thisdirect injection GC-FID method to detect the24samples, we found that the Traditional Chinese JujubeBrandy had a high ethanol content of53.4±8.2%v/v and6.70±1.50g/L (in100%ethanol) of methanol.Besides, both of ethanol and methanol contents in all samples exceeded the legal limits of GB2757-2012(SAC). The average value even exceeded the maximum legal limits more than2.35times.(2) Effects of Pectinase Treatment and Steam Boiling Treatment on Methanol content and Ethanolcontent in Traditional Chinese Jujube Brandy.In order to study the effects of Pectinase treatment and Steam Boiling Treatment on Methanolcontent and Ethanol content in Traditional Chinese Jujube Brandy, the solid-state fermentation ofCangzhou Golden Jujube was optimized. Methanol content and Ethanol content were analyzed andidentified by GC-FID. Pectinase treatment can significantly increase the Methanol content up to2.37g/L（100%,v/v）and Steam Boiling treatment can significantly reduce the content of Methanol up to3.65g/L（100%,v/v）compared with the conditional control group in Traditional Chinese Jujube Brandy，and both have no significant influence on Ethanol content in Traditional Chinese Jujube Brandy. Thewine samples of jujube materials without Pectinase Treatment but Steam Boiling treatment have amethanol content of0.87g/L (100%, v/v), below the2.00g/L (100%, v/v) in GB2757-2012(SAC).Therefore, through the Steam Boiling treatment can effectively reduce the Methanol Content inTraditional Chinese Jujube Brandy.(3) Effects of Different Fermentation Process Conditions on Methanol content and Ethanol contentin Traditional Chinese Jujube Brandy.In order to study the effects of Different Fermentation Conditions on Methanol content and Ethanolcontent in Traditional Chinese Jujube Brandy, the solid-state fermentation of Cangzhou Golden Jujubewas optimized. Methanol content and Ethanol content were analyzed and identified by GC-FID. Theresults shows that different Fermentation Time，Yeast Species，Yeast Additions and FermentationTemperature have no significant influence on absolute Methanol content，and each has significantinfluence on Ethanol content in Traditional Chinese Jujube Brandy. Therefore，through controlling thefermentation conditions can achieve the purpose of reducing the Methanol content in TraditionalChinese Jujube Brandy.