Important volateis composites for the aroma of jenipapo (American Genipa L.) e murici (crassifolia Byrsonima L. RICH). / Compostos volateis importantes para o aroma de jenipapo (Genipa americana L.) e murici (Byrsonima crassifolia L. RICH).

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The volatile compounds are responsible for the characteristic flavor of food. They are present in a wide interval of concentration, possessing varied chemical structure, beyond of being, generally heating labil. Usually the flavour of a product is constituted by hundreds of volatile compounds. However, only some compounds efftectivelly contribute to the overall aroma of the food. The knowledge of the important compounds contributing so the characteristic flavour of a product (will) allow the development of new aroma formulation and to monitor its quality. Isolation of the volatile compounds and, separation by high-resolution gas chromatography, identification by gas chromatography-mass spectrometry and olfactometry evaluation (Osme) were performed for two typical fruits of Brazilian Northeast, the murici (Byrsonima crassifolia L. Rich) and the genipap (Genipa americana L). The murici aroma is described in the literature as cheese with pineapple and cherry notes, while genipap is characterized by acid flavor and fruity notes. Headspace volatile compounds were collected by suction on porous polymer (Porapak Q). In order to standard the conditions for the isolation of volatile compounds, with the objective of obtaining a representative aroma of the sample, the volatile compounds were trapped in different conditions. The isolated volatile compounds were then analyzed by gas chromatography and sensory analysis. The best conditions for isolating the volatiles compounds of murici were a period of ttwo hours for the collecting time, acetone was chosen for the elution from the porous polymer. This same solvent showed the best capability of eluting the volatile compounds of genipap. The instrumental results agreed with those obtained by sensory analysis of the different isolation conditions. The best time period for collecting the volatile compounds of genipap was three hours. Forty-seven volatile compounds, present in the murici headspace, were detected by high-resolution chromatography, of which 41 were identified by gas chromatography-mass spectrometry and Kovats Indices, comprehending 97% of the total area. The most abundant chemical class was that of the esters (55%), followed by alcohols (31,5%). The major compounds were ethanol (28.3%), ethyl hexanoate (25.1%), butanoic acid (5,1%) and hexanoic acid (5,1%). The aromagrams revealed 37 odoriferou s volatiles compounds present in the headspace of fruit. Acetic, butyric and hexanoic acids presented the cheesy and fermented aroma, typical of this fruit. The 3-methylbutyric acid together to an unidentified compound and another not detected by the FID, presenting medium intensities also exhibited cheesy aroma. The esters such as ethyl butyrate, butyl butyrate and hexyl hexanoate were important to the fruity and sweety aroma. Fifty-nine volatile compounds from the headspace of genipap were detected by high-resolution chromatography, of which 42 compounds were identified, comprehending 90% of total area. Samples were characterized by a high number of esters and alcohols. The major compounds, considering the both harvest (2001 and 2002), were methyl octanoate, 2-heptanone, octanoic acid, 2-methylbutanoate acid and hexanoic acid. Several alcohols were identified for the first time such as ethanol, 2-methylpropanol, 2-pentanol, butanol, 2-methylbutanol, 3-methylbutanol, 2-heptanol, hexanol, 2-butoxiethanol, 2-nonanol and octanol. Some carbonyl compounds such as 2-pentanone, 4-methyl-2-pentanone, acetophenone, beyond the esters methyl 2-methylbutanoate, methyl 2-methylenebutanoate, methyl (Z)-3-hexenoate, methyl (Z)-3-octanoate, methyl benzoate, ethyl decenoate and methyl salicilate, one lactone, (hexalactone) and one hydrocarbon (1,3,5,7-cyclooctatetraene) were all identified for the first time too. Twenty-seven odorant compounds were determined by the olfactometry technique (Osme) and the hexanoic acid, 2-methylbutyric acid and a mixture of 2-methylbutanol, 3 methylbutanol and an unidentified compound (with 1700 Kovats indices) were responsible for the acid, fermented and cheesy aroma plus the unpleasant notes such as dirty socks. The compounds methyl 2-methylbutanoate, linalool, methyl octanoate, and a unidentified compound (IK 1850) were all responsible for the fruity and sweety notes.

ASSUNTO(S)

murici olfatometria murici (byrsonima crassifolia l. rich) espectrometria de massa aroma mass spectrometry jenipapo ( genipa americana l.) olfactometry jenipapo aroma

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