Comparação e avaliação do impacto físico-químico e sensorial da aplicação de patatina, quitosano e proteína de ervilha em vinho branco
Ficheiros
Data
2015
Título da revista
ISSN da revista
Título do Volume
Editora
Resumo
A utilização de proteínas de origem não animal como agentes clarificantes em vinhos brancos, carece ainda de estudos, nomeadamente sobre o seu impacto, quer a nível das características físico-químicas, quer a nível das características sensoriais dos vinhos. Assim, neste contexto, a presente dissertação pretende melhorar o conhecimento da utilização de colas vegetais e de polissacarídeos, bem como, verificar a sua eficiência para futura utilização a nível industrial. Neste sentido foram selecionadas várias colas, elementares ou misturas, à base de proteína de ervilha, proteína da batata (patatina) e quitosano, tendo sido comparados com agentes de colagem tradicionais, como o PVPP e o caseinato de potássio. Os ensaios foram realizados em vinho branco proveniente da região da Bairrada. O vinho ensaiado foi analisado em vários parâmetros físico-químicos e sensoriais, com o intuito de avaliar o impacto da colagem ao nível da sua composição fenólica, nomeadamente ácidos fenólicos, potencial de acastanhamento, cor, e a sua suscetibilidade ao pinking. Globalmente, pode-se concluir que as diferenças entre a aplicação das colas de origem não animal e as utilizadas tradicionalmente nas características do vinho não são significativamente diferentes (p> 0,05). A patatina, o caseinato de potássio, o PVPP e o quitosano diminuíram significativamente o índice de polifenóis totais, a mesma tendência foi observada para os resultados da concentração de flavonóides. Relativamente às concentrações de não-flavonóides, apenas a proteína de ervilha não demonstrou diferenças significativas relativamente à testemunha, todos os outros agentes clarificantes diminuíram este parâmetro. Com exceção do caseinato de potássio, todas as colas diminuíram a cor do vinho (A420nm) o que está de acordo com os resultados das características cromáticas. Relativamente ao potencial de acastanhamento, apenas o Mix 1 (PVPP, proteína de ervilha e celulose) diminuiu significativamente em relação ao controlo, apresentando também diminuição da concentração de catequina e do ácido cafeico relativamente aos outros agentes de colagem. Nos resultados da suscetibilidade ao pinking, todas as colas utilizadas melhoraram o vinho, excetuando a patatina. Quanto, à análise sensorial, apenas foram notadas diferenças significativas no Mix 2 (bentonite, PVPP, levedura e celulose) relativamente aos descritores frutado, floral e cor.
The use of non-animal proteins as fining agents in white wines, lacks of studies namely on their impact, on the physicochemical characteristics, as well as on wine sensorial characteristics. So, the aims of this study is to improve the knowledge of the use of vegetable protein and polysaccharides as fining agents, as well as to verify their efficiency for future use at an industrial scale. Several fining agents have been selected, such as pea protein, potato protein (patatin), chitosan and have been compared with traditional fining agents, such as PVPP and potassium caseinate. Assays were performed in white wine from Bairrada region. The wine was analysed concerning several physicochemical and sensory parameters, in order to know the impact on wine phenolic composition including phenolic acids, browning potential, colour, and pinking susceptibility. Overall, it can be concluded that the differences between non-animal and traditional fining agents are not significantly different (p > 0.05). Patatin, potassium caseinate, PVPP and chitosan reduced significantly total phenolic compounds. The same trend was observed for the flavonoid compounds. For non-flavonoid compounds, only pea protein showed no significant differences compared to control, all the other fining agents decreased this parameter. With exception of potassium caseinate, all fining agents decreased wine color (A420nm) which is in accordance with the results obtained for the chromatic characteristics. Regarding browning potential, only Mix 1 (PVPP, pea protein and cellulose) decreased significantly this parameter compared to control, this proving its decrease in the concentration of catechin and caffeic acid when comparing to the other fining agents. The pinking susceptibility was improved by all fining agents, except with patatin. Sensory analysis data showed that Mix 2 (bentonite, PVPP, inert yeast and cellulose) decreased significantly the descriptors fruity, floral and color.
The use of non-animal proteins as fining agents in white wines, lacks of studies namely on their impact, on the physicochemical characteristics, as well as on wine sensorial characteristics. So, the aims of this study is to improve the knowledge of the use of vegetable protein and polysaccharides as fining agents, as well as to verify their efficiency for future use at an industrial scale. Several fining agents have been selected, such as pea protein, potato protein (patatin), chitosan and have been compared with traditional fining agents, such as PVPP and potassium caseinate. Assays were performed in white wine from Bairrada region. The wine was analysed concerning several physicochemical and sensory parameters, in order to know the impact on wine phenolic composition including phenolic acids, browning potential, colour, and pinking susceptibility. Overall, it can be concluded that the differences between non-animal and traditional fining agents are not significantly different (p > 0.05). Patatin, potassium caseinate, PVPP and chitosan reduced significantly total phenolic compounds. The same trend was observed for the flavonoid compounds. For non-flavonoid compounds, only pea protein showed no significant differences compared to control, all the other fining agents decreased this parameter. With exception of potassium caseinate, all fining agents decreased wine color (A420nm) which is in accordance with the results obtained for the chromatic characteristics. Regarding browning potential, only Mix 1 (PVPP, pea protein and cellulose) decreased significantly this parameter compared to control, this proving its decrease in the concentration of catechin and caffeic acid when comparing to the other fining agents. The pinking susceptibility was improved by all fining agents, except with patatin. Sensory analysis data showed that Mix 2 (bentonite, PVPP, inert yeast and cellulose) decreased significantly the descriptors fruity, floral and color.
Descrição
Dissertação de Mestrado em Enologia
Palavras-chave
Vinho branco , Proteínas vegetais , Cor , Perfil fenólico , Perfil sensorial