Application Of Microwave And Infrared Technology In Liquor Aging

Chinese white liquor is deeply loved by people all over the world for its rich cultural background and unique taste.The unique flavor of white liquor is inseparable from its special production process.The production process of white liquor is generally composed of several steps such as fermentation,distillation,aging,blending.Among them,aging is the most crucial but time-consuming step.Unaged white liquor tastes sour and astringent hot,which contains a large number of harmful substances such as sulphide with a flavor of spicy.The purpose of the aging process is to reduce spicy taste in the liquor and the harmful substances such as sulfides and aldehydes,and increase esters and other aromatic substances in liquor,make liquor taste more soft and mellow,according with people's taste and national safety standards.The research object selected in this subject is Luzhou-favor Dukang Liquor.Firstly,Dukang Liquor is the research object.By using GC and NIR spectroscopy,the liquor-based spectrum is processed differently.Thus,the NIR quantitative analysis model of five typical flavor substances in liquor was established,which can quickly detect the content of these five flavor substances in liquor.Then,the liquor-based wines of different aging periods were taken as research objects,and the liquor was ripened by the technical treatment means of microwave radiation,infrared radiation and combination of the two kinds of radiation methods.The content of five typical flavor substances in liquor was quantitatively measured by the established quantitative analysis model of near-infrared spectroscopy,and the changes of these five substances in the process of radiation were analyzed,so as to establish a method which could shorten the aging time of liquor quickly.The following conclusions were obtained:1.After optimizing the spectral pretreatment of liquor by NIR spectroscopy,the content of flavor substances determined by national standard method was taken as the chemical value.Quantitative analysis models of ethyl acetate,acetic acid,ethyl lactate,ethyl caproate and hexanoic acid in liquor-based liquor were established by PLS.Validated the five models and the Predicted the determinant coefficients of five models between correction set and verification set,are 0.9736,0.9684,0.9435,0.9657 and0.9309,RMSECV are 5.63,9.28,6.80,12.75 and 14.74;The determinant coefficients R~2 of verification set are 0.9682,0.9628,0.9287,0.9686 and 0.9448,and the RMSEP are 6.34,9.75,7.35,9.34 and 12.35.The results show that the model has good precision and stability,and can be used to quantitatively detect the five flavor substances in liquor.2.The content of acetic acid,hexanoic acid and ethyl caproate decreased while the content of ethyl acetate and ethyl lactate increased during the natural aging process of liquor.By using microwave radiation and infrared radiation to treat different aging stages liquor,the results showed that these two radiation methods could accelerate the change of five flavor substances in liquor,accelerate the aging speed of liquor and change the taste of liquor.Between them,microwave radiation has more significant effect on the change of flavor substances in liquor.When the microwave irradiation time was 20-120 minutes,the trend of ethyl acetate content showed a Logistic curve.It was found that the Logistic model could be used to describe the change of ethyl acetate content in this period(r>0.95);When the microwave radiation temperature is50°C and the radiation time is 20-200 minutes,the change curve of caproic acid content in liquor approximates a parabola.The change trend of caproic acid content in liquor during this period can be described by parabolic equation(r>0.93).3.Microwave and infrared radiation were combined to treat liquor at different aging stages.The results showed that compound radiation could accelerate the change rate of five flavor substances in liquor,and the effect of accelerating liquor ripening was better than that of two separate radiation treatments.When the temperature of radiation treatment was combined with microwave 50°C and infrared 100°C,the change trend of ethyl caproate content in liquor showed an inverse function.It was proved by fitting that the inverse function could be used to describe the change of ethyl caproate content in liquor during that period(r>0.93);The change of ethyl lactate content in liquor was S curve when aging was accelerated by two radiation methods.It was proved by fitting that S-curve equation could be used to describe the change of ethyl lactate content in liquor irradiated by two methods(r>0.90).