Volatile compounds, quality attributes, mineral composition and pericarp structure of South African litchi export cultivars Mauritius and McLean's Red

BACKGROUND: The aim of this research was to identify the differences in volatile compounds, mineral composition, quality parameters and pericarp structure (at different fruit developmental stages) between two South African litchi export cultivars, Mauritius and McLean's Red, in order to provide a better understanding of the plant intraspecific variation. RESULTS: Citronellol and geraniol were predominant in the aroma profile of cv. Mauritius and conferred characteristic floral, rose, citrus and fruity aromas. In cv. McLean's Red, germacrene D was predominant in the sesquiterpene fraction. Germacrene D and muurolene are associated with a woody smell. Cv. Mauritius had lower soluble solid content/titratable acidity ratio and higher ascorbic acid content than cv. McLean's Red. Cv. McLean's Red had lower pericarp hue angle and higher anthocyanin concentration, which correlated negatively. Significant differences in fruit mineral content and pattern of cuticle accumulation were noted between the two cultivars. The parallel cuticular lines formed a network with intercellular ridges and heavy wax deposits in cv. McLean's Red. Cv. Mauritius showed higher weight loss at 25 degrees C, suggesting that the dense wax deposits and cuticle structure in cv. McLean's Red could limit moisture loss. CONCLUSION: This investigation shows evidence for the lack of sweet and rose-like fragrance in litchi cv. McLean's Red. It is the first study to compare volatile compounds responsible for the differing aromas of two South African litchi cultivars. Litchi cultivar improvement and breeding programmes are focused on expansion of the season and yield. The reported information is useful for selection of cultivars and for cultivar breeding programmes focusing on fruit quality and storage potential. (c) 2008 Society of Chemical Industry.