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Effect of lyophilisation in the black truffle (Tuber melanosporum) aroma: a comparison with other long-term preservation treatments (freezing and sterilization)

Author:
Marco, P., Campo, E., Oria, R., Blanco, D., Venturini, M. E.
Source:
Acta horticulturae 2018 no.1194 pp. 831-838
ISSN:
0567-7572
Subject:
Tuber melanosporum, aldehydes, canning, dimethyl sulfide, experts, freeze drying, freezing, gas chromatography, odors, olfactometry, olives, sensory evaluation, solid phase microextraction, truffles, volatile compounds
Abstract:
The aim of this work was to evaluate the effect of different preservation methods (freeze-drying or lyophilisation, traditional freezing and canning) on the aroma profile of Tuber melanosporum truffles. Volatile compounds were extracted by a solid-phase microextraction (SPME) technique and further analysed by gas-chromatography olfactometry, in order to monitor changes occurring in key-aroma compounds as a result of the technology applied. Samples were also submitted to descriptive sensory analysis by a panel of trained judges, and to a preference (ranking) test by a group of truffle experts. Data revealed that the aromatic profile of T. melanosporum freeze-drying truffle was less modified with respect to the genuine truffle aroma than the rest of products. Freeze-drying was the only treatment able to keep truffle key-compounds such as dimethylsulphide (DMS) and dimethyldisulphide (DMDS), evoking a typical black olives aroma. On the contrary, several aldehyde compounds (methional, hexanal and Z-4-heptenal) appeared as important odour molecules, which could influence the final aroma of the product. Descriptive analysis and expert's ranking showed the relative proximity among fresh and freezed-drying truffle, and confirmed the deep changes occurring in aroma as a consequence of the traditional freezing and canning process. Freeze-drying arises therefore as an adequate technique to better preserve the original aroma of fresh truffle.
Agid:
5960633