DEVELOPMENT OF ELECTRONIC NOSE MEASUREMENTS FOR MANGO ( MANGIFERA INDICA ) HOMOGENATE AND WHOLE FRUIT
DEVELOPMENT OF ELECTRONIC NOSE MEASUREMENTS FOR MANGO ( MANGIFERA INDICA ) HOMOGENATE AND WHOLE FRUIT
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发表时间：
2004
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通讯作者：
M. Lebrun;M. Ducamp-Collin;A. Plotto;K. Goodner;E. Baldwin
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作者：
M. Lebrun;M. Ducamp-Collin;A. Plotto;K. Goodner;E. Baldwin
拉丁美洲的芒果（cv. Tommy阿特金斯）购自当地佛罗里达超市，均质化，并通过静态顶空法取样用于挥发物分析。使用带有金属氧化物涂层或未涂层传感器（500 µL进样体积）的电子鼻（e-nose）分析一些材料，并通过配备极性Carbowax柱和火焰离子化检测器的气相色谱（GC）分析一些材料。分析匀浆的稀释度和匀浆体积以确定对电子鼻和GC顶空测量的影响。芒果匀浆（1.0、1.5和2.0 mL）用DI水稀释至原始浓度的50、25和12.5%。通过判别因子分析（DFA）分析所得电子鼻信号强度（由于与顶部空间中的挥发性化合物的非选择性相互作用而导致的金属氧化物传感器上的电阻变化），其结果是通过稀释因子分组，而不管样品大小。确定芒果匀浆2.0 mL和25%稀释度的组合是最佳的。这些结果与采用气相色谱（GC）顶空分析法对相同体积/稀释组合的芒果均质物的13种特征芒果挥发物的分析结果一致。顶空挥发物浓度一般随体积增大而增大，随稀释而减小，但也存在一些偏差和不一致。顶空浓度的增加与匀浆体积不成正比，表明基质对香气分配到顶空的影响，这对于不同的化合物是不同的。Whole Man- Goes（cv. Keitt和肯特）在弗拉的宅基地收获，在密封容器中放置3小时以积累足够的挥发物用于顶空分析。为了获得充足的信号和可重现的结果，需要将大的进样体积（2000 µL）注入电子鼻中，并根据挥发物释放到顶部空间的方式分离两种品种。
Mango fruit from Latin America (cv. Tommy Atkins), were purchased from a local Florida supermarket, homoge- nized, and sampled for volatile analysis by static headspace method. Some of the material was analyzed using an electronic nose (e-nose) with metal oxide coated or uncoated sensors (500 µL injection volume) and some by gas chromatography (GC) equipped with a polar Carbowax column and a flame ion- ization detector. Dilution of homogenate and homogenate vol- ume were analyzed to determine effect on e-nose and GC headspace measurements. Mango homogenate (1.0, 1.5, and 2.0 mL) was diluted with DI water to 50, 25, and 12.5% of original concentration. The resulting e-nose signal intensities (changes in resistance across the metal oxide sensor due to non-selec- tive interactions with volatile compounds in the headspace) were analyzed by discriminant factor analysis (DFA), which re- sulted in grouping by dilution factor, regardless of sample size. A combination of 2.0 mL and 25% dilution of mango homoge- nate was determined to be optimal. These results were com- pared to analysis of 13 characteristic mango volatiles by gas chromatography (GC) headspace analysis of the mango homo- genate for the same volume/dilution combinations. Concentra- tion of volatiles in the headspace generally increased with volume and decreased with dilution, but there were some ex- ceptions and inconsistencies. The increase in headspace con- centration was not directly proportional to the homogenate volume, indicating matrix effects on aroma partitioning into the headspace, which varied for different compounds. Whole man- goes (cv. Keitt and Kent) harvested in Homestead, Fla., were put in sealed containers for 3 hours to accumulate enough vol- atiles for headspace analysis. A large injection volume injected into the e-nose (2000 µL) was necessary to get ample signal and reproducible results, and separated the two varieties based on their volatile emission to the headspace.