Comparative analysis of volatile components of fresh and dried Tuber indicum truffles with different extraction methods

Abstract

SummaryTuber indicum Cook&Massee (T. indicum) is mainly distributed in China, and it is also the truffle species with the largest yield China. Investigation and utilisation of its volatile components is still limited. By using headspace solid‐phase microextraction (HS‐SPME) and gas chromatography–mass spectrometry (GC–MS), the volatile components of fresh and dried T. indicum were compared in this study. It was found that after hot‐air drying of T. indicum, 73 components were retained in the truffles, and the remaining components changed during the drying process. The relative contents of alcohols and aldehydes in the dried truffles decreased by approximately 40% and 83%, respectively, while the relative contents of acids and esters increased by approximately 14 times and 5.5 times respectively. The drying process severely disrupts the flavour of the truffles. In advance, three extraction methods (steam distillation, Soxhlet extraction and supercritical CO2 fluid extraction [CO2‐SFE]) were performed on dried and fresh T. indicum, and their volatile components were compared. The results indicated that the alkanes extracted from fresh and dried truffles by steam distillation and Soxhlet extraction accounted for 30%–48%, while a richer variety of compounds were extracted from the two truffles by CO2‐SFE, with acids, esters and alcohols together amounting to approximately 70% in quantity, and they exceeded 95% in relative content. A richer variety of volatile compounds was extracted, and more fatty acids which yielded greasy, creamy, sweet and mushroomy aromas were enriched by CO2‐SFE compared to steam distillation and Soxhlet extraction. Therefore, CO2‐SFE extraction is a suitable method for extracting volatile components from T. indicum.