UBC Theses and Dissertations
Classification of the characteristics of two mango cultivars harvested at different stages of maturity using gas chromatography and sensory data Vodovotz, Yael
The classification of the characteristics of two Mexican mango varieties (Tommy Atkins and Haden) ripened under two conditions (in cold storage and on the tree) was attempted using several multivariate analysis techniques. The aroma of the different mango purees was analyzed using both capillary gas chromatography and sensory analysis. A new portable gas chromatograph (SRI model 8610, Torrance, CA) equipped with a purge and trap was used and the area count of relevant peaks calculated. These results and those obtained from a sensory panel comprised the classification factors. In addition, parameters such as the Magness Taylor pressure values, pH and acid/sugar ratio were determined. Two familiar classification techniques namely Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were used as well as a new program developed in our laboratory: PCA- Similarity (PCA-SIM). Results showed that differences exist between varieties as well as ripening conditions when analyzed both by GC and sensory techniques. Distinct groups were formed when the results of these techniques were independently subjected to LDA and PCA-SIM. PCA was more successful as a variable reduction technique than a classification method. Although both GC and sensory methods were successful in characterizing the differences between the groups, one could not replace the other since no correlation was found between the two methods. The other physico/chemical parameters were useful, but only to a limited extent, and none could account for both differences between varieties and ripening conditions.
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