Produção e caracterização de aromas de frutas por microrganismos pectinoliticos utilizando-se residuos agroindustriais. / Production and characterization of fruits flavor for pectinolytic microorganisms using agro-industrial residues.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Pectinases were some of the first enzymes used in commercial applications of wines and fruit juices since 1930 and their use has increased considerably, specially in food, brewery and wine, textile, pulp and paper industries. Today, these enzymes account for approximately 20% of the world enzyme market. Plants, fungi, yeasts, and bacteria naturally produce these enzymes. These microorganisms can be inoculated in a medium containing agro-industrial residues from processing agricultural products, used as carbon source for the production of value-added products such as ethanol, enzymes, proteins, amino acids and flavor compounds. Flavor is the result of combination of chemical compounds and several functional groups such as alcohols, acids, aldehydes, ketones, lactones and esters. It can determine the quality of food and lead to consumer acceptance or rejection of a product. The flavor compounds synthesis by biotechnological processes play an important role due to an increasing consumer preference natural food additives and other compounds from biological origin. Several microorganisms isolated from coffee seeds and leaves, soil taken from plantations and waste water from the coffee seeds washing process due to their capacity to produce pectinolytic enzymes in clear halos around colonies by plate assay. From 104 strains 18 strains were inoculated in medium containing pectin as carbon source and were fermented at 30°C and 100 rpm for 96 hours to determine pectinolytic activity of polygalacturonase (PG) and pectin lyase (PMGL). These microorganisms were inoculated in medium containing fructose and yeast extract and were fermented at 25°C and 100 rpm to verify the capacity of flavor compound production. The strains 2, 9, 20, 39, 70, 74, and 99 showed activity units of PG higher than 80 ?mol galacturonic acid/mL/minute and strains 17, 18, 31, 37, 73, 74 and 125 showed activity units of PMGL higher than 1000 ?mol unsatured products/mL/minute. The microorganisms 13, 70, 73, 74, 125 and 144 showed good descriptors of flavor perceived and the most intensities of flavor according non trained painel listing. The microorganisms 70, 73, 74, and 144 were selected to perform fermentation in medium containing coffee husk and grape bagasse at 25°C and 100 rpm for 120 hours, because these microorganisms are able to produce flavor by pectin degradation. In the both media, the flavor compounds showed descriptors as frutal, sweet, floral, ferment, acid and solvent. The compounds were separated and identified by gas chromatography and mass spectrometry. Acetone, ethyl acetate, ethanol, isobutanol, isopentyl alcohol (amyl alcohol), acetoin (3-hydroxi-2-butanone), acetic acid, isobutyric acid, butyric acid, 2-methyl-butanoic acid, benzyl alcohol and 2-phenyl ethanol were produced in different combinations and different concentrations by the 4 microorganisms.

ASSUNTO(S)

gas chromatography cromatografia de gas bagasse pectina fermentation industrial residues flavor aroma residuos industriais pectin fermentação

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