Caracterização fisico-quimica e avaliação de metilpirazinas no desenvolvimento no sabor, em dez cultivadores de cacau (Theobroma cacao L) produzidos no Estado de São Paulo

AUTOR(ES)
DATA DE PUBLICAÇÃO

1994

RESUMO

Ten coco a clones (Theobroma cacao L) were studied with respect to their physical, chemical and sensory characteristics and the behavior of some pyrazine derivatives during roasting. The cultivars were obtained from the Experimental Station at Pariquera-Áçú (S.P.), being part of the collection belonging to the Campinas Agronomy Institute. With the objective of determining the behavior of these clones in the region under study, the following characteristics were measured: seed mass per fruit, average mass and size of seed. The following gave exceptional results: clones DF 667, DF 668, ICS 60 and DF 613. Of the clones studied eight gave average kernel weights of 1.35-2.21g, well above the commercial requirement (1.2g). All the clones studied presented high levels of cocoa butter, between 51.2 and 57.2% on a dry weight basis. The sensory evaluation of the beans roasted at 145°C for 14 minutes, showed no significant difference at the 5% level with respect to the aroma and overall flavour amongst the clones studied, with the exception of the acid taste. The results demonstrated that the four methylpyrazines are already in the raw cocoa beans before roasting, but up to 89% of 2,5-di; 87% of 2,3-di; 92% of 2,3,5tri and 55% of 2,3,5,6-tetramethylpyrazine were produced, probably by the MaiUard reaction, during roasting. The study of the evolution of the alkylpyrazines during roasting showed a linear increase in concentration during the 14-minute roasting period considered best for the organoleptic trial. Immediately after this period a rapid decrease in the concentration of tetramethylpyrazine, possibly caused by the end of the roascing process, was observed. Two techniques were used for the extraction of aromatic compounds: 1) extraction with a LIKENS &NICKERSON micro-extractor, as modified by GODEFROOT et alii (1985) and using pentane:ethyl ether 2:1, as solvent, and 2) extraction with pressurized C02 concentrated on the polymer porapak Q. In both cases the compounds were separated by gas chromatography using a capillary column of melted silica, D.B.Wax liquid phase and a flame ionization detector. Quantification was effected using 4 ethyl pyridine as internal standard. The method of aromatic compound extraction with pressurized C02 followed by concentration of the extract in porapak Q polymer, showed advantages over the method of steam stripping and Goncentration in a micro extrator. The extraction with pressurized C02 increased the extraction efficiency from 14 to 27% as a function of the type of methylpyrazyne

ASSUNTO(S)

cacau - cultivo - são paulo avaliação sensorial metilpirazinas

ACESSO AO ARTIGO

Documentos Relacionados