葡萄劣变过程中挥发性物质的FTIR光谱分析  

Analysis of Volatiles during Grape Deterioration Using FTIR

作　　者：王文重[1,2] 董大明[1] 郑文刚[1] 韩峻峰[2] 叶松[2] 矫雷子[1] 赵贤德[1] 

机构地区：[1]北京市农林科学院国家农业信息化工程技术研究中心,北京100097 [2]桂林电子科技大学电子工程与自动化学院,桂林541004

出　　处：《化学学报》2013年第2期234-238,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(No.31101748;31271614);北京市农林科学院创新能力建设专项(No.KJCX201102001)资助~~

摘　　要：葡萄在运输和贮藏过程中极易发生变质,对葡萄劣变进行预警可有效降低大规模腐败的风险.研究了葡萄在劣变过程中所产生挥发性物质的FTIR光谱特性.实验证明了葡萄劣变中挥发性物质的主要成分为乙酸乙酯、乙醇、二氧化碳和水汽.通过光谱定量化分析研究挥发性物质在劣变中的变化规律,发现葡萄在劣变开始发生时的气体释放速率会发生阶跃性变化.论文采用主成分分析法(PCA)对挥发性物质的红外光谱进行了分类,可以准确地区分未变质、轻度变质和重度变质的葡萄.论文的结论说明挥发性物质的FTIR光谱分析可以有效鉴别贮藏中葡萄的劣变程度.而且由于挥发性气体在葡萄劣变中的阶跃变化性质,使这种鉴别方法具有不易受葡萄数量、存放方式影响的优点.论文的研究为葡萄劣变监测设备研制提供了理论和技术基础.Grape is very perishable in transportation and storage,so its early warning is particularly important to lower the risks of large-scale deterioration.In order to study grape deterioration process,we analyzed the volatile compounds from grapes using Fourier transform infrared（FTIR） spectroscopy.Several grapes were put in the sample compartment of the FTIR spectrometer for 2 h per day.Then,the volatile compounds vaporized from the grapes were measured directly using the spectrometer.A high energy ceramic IR-source was used to improve the signal-to-noise ratio.We collected the FTIR spectrum before sample was put in as a background to eliminate the influence of air.Spectral signatures of the volatiles from grapes were analyzed and used to classify the grape samples into deterioration or not.By spectral analysis,the volatile mainly includes ethyl acetate,ethanol and carbon dioxide.The above three volatile vaporized more and more from the grapes during deterioration process.We also found that the release rates of volatile compounds get its highest value when the grapes just started deteriorating,so,this value could be used to monitor the beginning of deterioration.The methods to classify grapes deterioration levels were also studied.Firstly,grape deterioration processes were divided into three stages,fresh,slight deterioration and severe deterioration,by appearance and sensory evaluation.Then,a principle compounds analysis（PCA） was used for unsupervised classification to FTIR spectra.Results showed that this method could distinguish grapes into fresh and deterioration by choosing proper data pre-processing algorithms.This paper provides a new way to study the fruit deterioration mechanism,and premise a foundation for developing early-warning equipment for evaluation and monitoring fruit deterioration during its storage and transportation.Furthermore,because of the step change of release rates of volatile compounds at the beginning of deterioration,this kind of classifying method and monitoring system may not in

关 键 词：葡萄劣变 挥发性物质 傅里叶变换红外光谱 主成分分析 分类 

分 类 号：TS255.1[轻工技术与工程—农产品加工及贮藏工程] O657.33[轻工技术与工程—食品科学与工程]