Carotenoides são importantes constituintes de alimentos por sua coloração e por seus produtos de degradação gerarem compostos voláteis em alimentos. Compostos de aromas derivados de carotenoides estão distribuídos na natureza, constituem precursores de aromas importantes em alimentos como frutas e em flores. Apresentam alto potencial aromático e, por isso, são de grande interesse para as indústrias de aromas e fragrâncias. Neste trabalho, mais de 300 microrganismos foram selecionados pelo método da placa, de acordo com sua capacidade de degradar carotenoides presentes no meio de cultura. Cerca de 80 linhagens apresentaram capacidade de produção de aromas e 7 cepas apresentaram descritores e intensidades de aromas de interesse, segundo um painel não treinado de provadores, sendo selecionadas e submetidas à fermentação submersa para produção de compostos aromas derivados de β-caroteno. β-Ionona foi o principal produto obtido da degradação de β-caroteno, encontrado em maiores concentrações nas linhagens CS1 (34,0 mg.L-1) e CF9 (42,4 mg.L-1) em 72 e 24 horas de fermentação nos meios de cultura sem e com pré-inóculo, respectivamente. Os compostos β-damascona e pseudoionona foram encontrados em baixas concentrações, 1,1,6-trimetil-1,2,3,4-tetraidronaftaleno (TTN) foi tentativamente identificado e apocarotenoides, provavelmente obtidos da clivagem da parte central do carotenoide, foram detectados.

Carotenoids are important constituents of food due to their color and because their degradation products generate important volatile compounds in foods. Aroma compounds derived from carotenoids are widely distributed in nature, and they are precursors of many important aromas in foods such as fruits and in flowers as well. They present high aromatic potential and are therefore of great interest to the industries of aromas and fragrances. In this study, more than 300 previously isolated microorganisms with potential for biotransformation of β-carotene present in the culture medium were selected using the plate method; about 80 strains presented capacity to produce aroma compounds and 7 strains were selected by an untrained panel of tasters to generate aroma compounds. The β-ionone was the main compound produced by CS1 (34.0 mg.L-1) and CF9 (42.4 mg.L-1) microorganisms at 72 and 24 hours of fermentation, cultured with and without pre-inoculation, respectively. The β-damascone and pseudoionone were found in low concentrations, 1,1,6-trimethyl-1,2,3,4-tetrahydronaphthalen (TTN) was tentatively identified and other compounds such as apocarotenoids, apparently obtained from the cleavage of the central part of the carotenoid, were detected.

Carotenoids are widely distributed in nature, providing yellow, orange or red color in a great number of vegetables, microorganisms and in some animals. Carotenoids act as biological antioxidants and seem to play an important role in human health by protecting cells and tissues from the damaging effects of free radicals and singlet oxygen. Several authors describe the oxidative cleavage of carotenoids in flavor compounds as occuring through chemical or photochemical degradations or through biotechnological processes. Biotransformation of carotenoids seems to be a reasonable alternative to produce flavor compounds since these compounds are considered 'natural' ingredients. In this work we describe the properties of some carotenoids, as well as biotechnological approaches to obtain its oxyfunctionalized derivatives.

Pectic substances are structural heteropolysaccharides that occur in the middle lamellae and primary cell walls of higher plants. They are composed of partially methyl-esterified galacturonic acid residues linked by alpha-1, 4-glycosidic bonds. Pectinolytic enzymes are complex enzymes that degrade pectic polymers and there are several classes of enzymes, which include pectin esterases, pectin and pectate lyases and polygalacturonases. Plants, filamentous fungi, bacteria and yeasts are able to produce pectinases. In the industrial world, pectinases are used in fruit juice clarification, in the production of wine, in the extraction of olive oil, fiber degumming and fermentation of tea, coffee and cocoa.

As pectinases são enzimas produzidas naturalmente por plantas, fungos, leveduras e bactérias. Estes microrganismos podem ser inoculados em meios contendo resíduos agroindustriais utilizados como fonte de carbono para a produção de compostos de maior valor agregado, como enzimas, etanol, proteínas, aminoácidos e compostos de aroma. Vários microrganismos foram isolados e selecionados quanto à produção de enzimas pectinolíticas pelo método da placa, através de zonas claras de degradação de pectina ao redor da colônia. De 104 linhagens testadas, 18 foram selecionadas para fermentarem em meio líquido, contendo pectina para a determinação de atividade de poligalacturonase (PG) e de pectina liase (PMGL), e em meio frutose/extrato de levedura para produção de aromas. As linhagens 2, 9, 20, 39, 70, 74 e 99 apresentaram unidades de atividade de PG superiores a 80 µmol de ácido galacturônico/mL/min, as linhagens 17, 18, 31, 37, 73, 74 e 125 apresentaram unidades de atividade de PMGL superiores a 1000 etamol de produtos insaturados/mL/min e as linhagens 13, 70, 73, 74, 125 e 144 apresentaram os melhores descritores e as maiores intensidades de aromas percebidos por um painel não treinado de provadores.

Pectinases are enzymes used in food industries, produced by plants, fungi, yeasts and bacteria. These microorganisms can be inoculated in a medium containing agro-industrial residues from processing agricultural products, used as a carbon source to produce value-added products such as enzymes, ethanol, proteins, amino acids and flavor compounds. Several microorganisms were isolated and selected due to their capacity to produce pectinolytic enzymes in clear halos around colonies by plate assay. From 104 strains, 18 were inoculated in a medium containing pectin as a carbon source and the pectinolytic activities of polygalacturonase (PG) and pectin lyase (PMGL) were determined. Strains 2, 9, 20, 39, 70, 74, and 99 showed activity units of PG higher than 80 µmol galacturonic acid/mL/minute. Strains 17, 18, 31, 37, 73, 74 and 125 showed activity units of PMGL higher than 1000 etamol unsaturated products/mL/minute. Strains 13, 70, 73, 74, 125 and 144 showed good signs of flavor noticed in the fructose and yeast extract medium and the most intense flavor according to a non-trained board of tasters.