Analysis of volatile aroma compounds of fresh chilli (Capsicum annuum) during stages of maturity using solid phase microextraction (SPME)

Volatile aroma compounds of fresh premium grade commercial chilli (Capsicum annuum var annuum cv. Kulai) at three ripening stages (green, turning, red) were investigated using solid phase microextraction (SPME). Using statistical optimization method, the optimum parameter for the absorption of six principal compounds of chilli aroma, namely hexanal, 2-isobutyl-3-methoxypyrazine, 2,3-butanedione, 3-carene, trans-2-hexenal and linalool, on SPME fibres was found to be 30 min at 60°C. The presence of these important aroma compounds in fresh chilli was confirmed by their GC retention time and mass spectra. During ripening, hexanal (green aroma) and 2-isobutyl-3-methoxypyrazine (grassy aroma) were found to be significantly decreased. Sweet, fruity attributes represented by such compound as 2,3-butanedione, 3-carene, trans-2-hexenal and linalool were found to increase during ripening. The profile of chilli aroma compounds was successfully evaluated with ease using SPME. The method can be applied to determine the quality of the commercial chilli or other volatile compound as an alternative to full-scale headspace analysis.