HS-SPME study of the volatile fraction of Capsicum accessions and hybrids in different parts of the fruit

Abstract

The fruit volatile fraction of 8 Capsicum annuum and 2 Capsicum chinense accessions as well as 6 intra-specific and 2 inter-specific hybrids developed from crossings between them was isolated by headspace-solid phase microextraction (HS-SPME), and analized by gas chromatography-mass spectrometry (GC-MS). Samples of fruit flesh and placenta plus seeds were analysed separately. Several terpenoids, esters, alkanes, as well as other minor compounds relevant for the aroma, including 3-isobutyl-2-methoxypyrazine, methyl salicylate, and alpha-ionone, were identified. Remarkable differences, both qualitative and quantitative, were found for the volatile composition of the parent accessions. In hybrids a number of compounds comprised between or higher than in the corresponding parents was detected, while intermediate or transgressive inheritance for both total and individual volatiles was observed. Differences between fruit flesh and placenta/seeds were mostly quantitative, as we could not detect compound-specificity in these tissues. In most cases, both total and individual volatiles were higher in the placenta/seeds samples. This effect was particularly important in hybrids, with levels of total volatiles in the placenta up to 14-fold those of the fruit flesh. Our results suggest that there are ample opportunities for improving the aroma of Capsicum peppers by means of hybridization.