| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.51 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O vinagre de mel é um produto obtido por dupla fermentação, fermentação alcoólica e acética. A partir da fermentação alcoólica do mel obtém-se o hidromel, que é uma bebida alcoólica que contem entre 9-18% (v/v) de etanol. O vinagre de mel é obtido pela fermentação acética do hidromel. O presente trabalho teve como objetivo estudar a otimização da produção de vinagre de mel, utilizando dois tipos de mel, claro (eucalipto) e escuro (urze), e duas estirpes de leveduras, LSA ICV D47 e LSA QA23. Foi avaliado o teor de compostos fenólicos e flavonoides totais nos diversos produtos, mel, hidromel e vinagre de mel. Foi também efetuado um estudo preliminar sobre o efeito de várias colas na clarificação do hidromel.
As fermentações alcoólicas foram monitorizadas diariamente através da leitura da densidade ótica, viabilidade das células e consumo dos açúcares redutores. A qualidade do hidromel, no fim das fermentações, foi avaliada através da determinação de vários parâmetros enológicos, como o SO2, azoto assimilável, acidez total, teor alcoólico, acidez volátil, pH e açúcares redutores. Foram ainda avaliados os produtos resultantes do metabolismo (etanol, glicerol e ácido acético) por Cromatografia líquida de alta eficiência (HPLC) com um detetor de índice refrativo RI-4.
Os resultados obtidos indicam que o mel escuro foi mais adequado para a produção de hidromel. Quando comparadas as duas estirpes de leveduras, apesar das diferenças na sua “performance” fermentativa não serem relevantes, a estirpe LSA QA23 foi mais adequada para a produção de hidromel. O rendimento em etanol das fermentações alcoólicas variou entre 48,37 e 53,33%.
Na produção de vinagre de mel foram utilizadas culturas puras de bactérias acéticas isoladas de vinhos tintos. As fermentações acéticas foram monitorizadas diariamente através da quantificação do consumo de etanol e da produção de ácido acético. A produção deste composto não correu como o esperado, uma vez que em ambos os hidroméis, só obtivemos um teor de ácido acético de 2g/L. A utilização de culturas puras de bactérias acéticas, a não adição de hidromel ao longo do tempo e o arejamento insuficiente poderão justificar esta situação.
The honey vinegar is a product obtained by double fermented, alcoholic and acetic fermentation. From the alcoholic fermentation of honey obtained mead, which is an alcohol that contains from 9-18% (v / v) ethanol. The honey vinegar is obtained by acetic fermentation of mead. The present work aimed to study the optimization of the production of honey vinegar, using two types of honey, of course (eucalyptus) and dark (Heather), and two yeast strains, D47 and ICV LSA LSA QA23. The content of phenolic compounds and total flavonoids in different products, honey, mead and honey vinegar was evaluated. Was also conducted a preliminary study on the effect of various glues in mead. The fermentations were monitored daily by reading the optical density, cell viability and consumption of the reducing sugars. The quality of mead at the end of fermentation, was evaluated by determining various enological parameters such as SO2, assimilable nitrogen, total acidity, alcohol, volatile acidity, pH and reducing sugars. We also assessed the products of metabolism (ethanol, glycerol and acetic acid) by High-performance liquid chromatography (HPLC) with a refractive index detector RI-4. The results indicate that the dark honey was more adapt for the production of mead. When comparing the two yeast strains, despite the differences in its "performance" are not relevant fermentation, the LSA QA23 strain was more adapt for the production of mead. The ethanol yield from fermentations ranged between 48.37 and 53.33%. In the production of honey vinegar pure cultures of acetic bacteria isolated from red wines were used. The aseptic fermentations were monitored daily by measuring the consumption of ethanol and acetic acid production. The production of this compound did not go as expected, since in both meads only obtained an acetic acid concentration of 2g/L. The use of pure cultures of acetic bacteria, not to the addition of mead over time and insufficient ventilation may justify this.
The honey vinegar is a product obtained by double fermented, alcoholic and acetic fermentation. From the alcoholic fermentation of honey obtained mead, which is an alcohol that contains from 9-18% (v / v) ethanol. The honey vinegar is obtained by acetic fermentation of mead. The present work aimed to study the optimization of the production of honey vinegar, using two types of honey, of course (eucalyptus) and dark (Heather), and two yeast strains, D47 and ICV LSA LSA QA23. The content of phenolic compounds and total flavonoids in different products, honey, mead and honey vinegar was evaluated. Was also conducted a preliminary study on the effect of various glues in mead. The fermentations were monitored daily by reading the optical density, cell viability and consumption of the reducing sugars. The quality of mead at the end of fermentation, was evaluated by determining various enological parameters such as SO2, assimilable nitrogen, total acidity, alcohol, volatile acidity, pH and reducing sugars. We also assessed the products of metabolism (ethanol, glycerol and acetic acid) by High-performance liquid chromatography (HPLC) with a refractive index detector RI-4. The results indicate that the dark honey was more adapt for the production of mead. When comparing the two yeast strains, despite the differences in its "performance" are not relevant fermentation, the LSA QA23 strain was more adapt for the production of mead. The ethanol yield from fermentations ranged between 48.37 and 53.33%. In the production of honey vinegar pure cultures of acetic bacteria isolated from red wines were used. The aseptic fermentations were monitored daily by measuring the consumption of ethanol and acetic acid production. The production of this compound did not go as expected, since in both meads only obtained an acetic acid concentration of 2g/L. The use of pure cultures of acetic bacteria, not to the addition of mead over time and insufficient ventilation may justify this.
Description
Keywords
Ácido acético Etanol Hidromel Mel Vinagre de mel