Group-type quantitative analysis of flavor compounds in ripening avocados.

Abstract

Avocados are a superfood gaining popularity in people's diet. Profiling and quantifying the volatiles associated with flavor can further help in understanding the fruit. However, this is challenging due to relatively low abundance of volatile compounds. The complex mixtures inherent to avocado flavor can result in coelutions using classical chromatographic techniques. To overcome these challenges, solid-phase microextraction was used to extract and preconcentrate volatiles, then separated and quantified using two-dimensional gas chromatography with a flame ionization detector. This technique enhances separation power and produces well-ordered chromatograms, allowing for templated groupings of compounds of similar chemical composition into regions. Using the flame ionization detector, an average response factor was determined and used for quantification of these templated group-type regions, as well as individual compounds. This group-type quantification improved the overall precision of compound classes in 50 avocados by at least a factor of 2, when compared to that of the individual components. Overall, the abundance of associated flavor groups, such as terpenes and alcohols decreased, whereas aldehyde groups remained constant throughout ripening. The combination of solid-phase microextraction with two-dimensional gas chromatography and group-type quantification allows for an overall better understanding of the volatiles associated with flavor of avocados.