Abstract (EN):
The volatile fraction of raw materials plays a fundamental role in the quality of final food products as well as concerning consumers' acceptability. In Tras-os-Montes, a region with strong tradition in olive growing, the quality of olive products (olive oil, table olives and olive paste) is undoubtedly related with the volatile fraction of the fruits, being preponderant the varietal factor. In this sense, it was intended to characterize the volatile fraction of three of the most representative olive cultivars from Tras-os-Montes (cvs. Cobrancosa, Madural and Verdeal Transmontana) by HS-SPME and GC/MS. The olives were collected close to the optimal harvest time (maturation index = 3; 3rd week of October 2011), with 5 samples per cultivar. The different cultivars affected both qualitatively and quantitatively the volatile fraction being olives mainly characterized by hydrocarbons (toluene), alcohols ((Z)-3-hexen-1-ol and 1-hexanol), aldehydes (hexanal, heptanal, benzaldehyde, nonanal, and decanal) esters ((Z)-3-hexen-1-ol acetate), ketones (6-methyl-5-hepten-2-one), monoterpenes (a-pinene, limonene, L-menthol) and sesquiterpenes ((+)-cyclosativene, alpha-copaene, amuurolene). Hydrocarbons, alcohols and aldehydes were the most abundant chemical classes, being toluene, (Z)-3-hexen-1-ol and nonanal the volatile compounds in higher amounts. (Z)-3-hexen-1-ol together with hexanal are associated to green sensations and cut grass, a sensory characteristic considered an attribute. The volatile fraction is specific according to the olive variety in study. An aspect to be considered during the elaboration of products based on olives, also taking in account consumers' acceptability.
Idioma:
Português
Tipo (Avaliação Docente):
Científica
Nº de páginas:
6