Utility of Metabolomics toward Assessing the Metabolic Basis of Quality Traits in Apple Fruit with an Emphasis on Antioxidants

A gas chromatography–mass spectrometry approach
was employed
to evaluate the use of metabolite patterns to differentiate fruit
from six commercially grown apple cultivars harvested in 2008. Principal
component analysis (PCA) of apple fruit peel and flesh data indicated
that individual cultivar replicates clustered together and were separated
from all other cultivar samples. An independent metabolomics investigation
with fruit harvested in 2003 confirmed the separate clustering of
fruit from different cultivars. Further evidence for cultivar separation
was obtained using a hierarchical clustering analysis. An evaluation
of PCA component loadings revealed specific metabolite classes that
contributed the most to each principal component, whereas a correlation
analysis demonstrated that specific metabolites correlate directly
with quality traits such as antioxidant activity, total phenolics,
and total anthocyanins, which are important parameters in the selection
of breeding germplasm. These data sets lay the foundation for elucidating
the metabolic basis of commercially important fruit quality traits.