ANALYSIS OF VOLATILE COMPOUNDS IN THE CIT RUS PEELS USING 6 SEMICONDUCTOR GAS SENSORS

Mixtures of two compounds and volatiles in the Citrus peels were analy zed by six semiconductor gas sensors. From the result of mixed compoun ds, responses of semiconductor gas sensors were affected by vapor pres sures of individual compounds. It was found that sensor responses as w ell as vapor pressures changed by the solubility and the ratio of the concentration of compounds dissolved in the solutions. On the other ha nd, Citrus sudachi, Citrus limone, Citrus iyo, two Citrus sinensis, an d two Pummelos were used for the sensor analysis as the samples. Facto r analysis of the response patterns of six gas sensors was conducted a nd then factor 1 and factor 2 scores were plotted on a two dimensional diagram. The factor scores of Citrus sudachi and Citrus limone were l ocated in the similar area and formed individual groups. However, the other orange families except one Pummelo were dispersed on the close a rea of the diagram. One Pummelo was dispersed widely on the diagram. T he discriminant analysis of response data of semiconductor gas sensors for Citrus peels distinguished more than 70% of probability as the re sponse of the correct fruit. We tried to explain the distribution of t he factor scores of Citrus fruits by sensor responses to model mixture s of 5 compounds (limonene, beta-pinene, gamma-terpinene, myrcene, and linalool) found in individual fruits as the main components. However, it could not be explained by the small number of compounds well becau se of the high similarity of sensor responses among limonene, gamma-te rpinene and myrcene.