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Advisor(s)
Abstract(s)
O grau de maturação é um dos principais fatores que influi na composição e bioactividade de azeitonas de mesa,
bem como na obtenção de azeites de qualidade. Neste sentido, no presente trabalho foram estudadas as
alterações sofridas por frutos da Cv. Cobrançosa ao nível da sua actividade antioxidante e composição fenólica
ao longo da maturação do fruto, entre finais de setembro e novembro. A atividade antioxidante foi avaliada pelo
efeito bloqueador de radicais livres de DPPH e pelo método do poder redutor e o perfil fenólico foi avaliado por
cromatografia líquida de alta resolução com um detector de díodos (HPLC/DAD).
Foram identificados e quantificados sete compostos fenólicos que variaram ao longo da maturação do fruto. A
oleuropeína foi o composto mais abundante nas fases iniciais, reduzindo o seu teor drasticamente ao longo da
maturação até ao seu desaparecimento completo. O hidroxitirosol foi o composto maioritário nas fases de
maturação intermédias e avançadas. O teor total em compostos fenólicos variou entre 33856 mg/kg e 960 mg/kg,
respectivamente, da primeira para à última data de amostragem. O potencial poder redutor dos frutos da Cv.
Cobrançosa foi reduzindo ao longo da maturação, facto que se revelou estar relacionado com a composição
fenólica.
A aplicação de técnicas quimiométricas ajudou a entender o efeito da maturação ao nível da actividade
antioxidante e perfil fenólico. Os dados obtidos poderão também auxiliar na determinação de um momento
óptimo de colheita para a Cv. Cobrançosa, de modo a melhorar as propriedades e composição tanto de azeite
como de azeitonas de mesa.
Olive’s maturation degree is one of the main factors influencing the composition and bioactivity of table olives, as well as the production of high quality olive oils. In this sense, olive fruits from Cv. Cobrançosa were studied for their antioxidant activity and phenolic composition during maturation, between September and November. Antioxidant activity was assessed by the scavenging effect on DPPH free radicals and reducing power methods and the phenolic profile was assessed by high-performance liquid chromatography with diode array detection (HPLC/DAD). During olives maturation seven phenolic compounds were identified and quantified. Oleuropein was the most abundant compounds in the earlier phases of maturation, followed by an intense decrease up to its complete disappearance. Hydroxytyrosol was the most abundant compound in middle and advanced maturation phases. Total phenols content varied from 33856 mg/kg and 960 mg/kg from first to the last sampling date. The reducing power of Cv. Cobrançosa olive fruits decreased during the maturation process, a fact revealed to be related with the phenolic composition. The application of chemometric tools helped to understand the effect of maturation process on antioxidant activity and phenolic profile. The data obtained could also aid in the determination of a proximate optimum harvest date for Cv. Cobrançosa, so that table olives and olive oil composition and properties could be enhanced.
Olive’s maturation degree is one of the main factors influencing the composition and bioactivity of table olives, as well as the production of high quality olive oils. In this sense, olive fruits from Cv. Cobrançosa were studied for their antioxidant activity and phenolic composition during maturation, between September and November. Antioxidant activity was assessed by the scavenging effect on DPPH free radicals and reducing power methods and the phenolic profile was assessed by high-performance liquid chromatography with diode array detection (HPLC/DAD). During olives maturation seven phenolic compounds were identified and quantified. Oleuropein was the most abundant compounds in the earlier phases of maturation, followed by an intense decrease up to its complete disappearance. Hydroxytyrosol was the most abundant compound in middle and advanced maturation phases. Total phenols content varied from 33856 mg/kg and 960 mg/kg from first to the last sampling date. The reducing power of Cv. Cobrançosa olive fruits decreased during the maturation process, a fact revealed to be related with the phenolic composition. The application of chemometric tools helped to understand the effect of maturation process on antioxidant activity and phenolic profile. The data obtained could also aid in the determination of a proximate optimum harvest date for Cv. Cobrançosa, so that table olives and olive oil composition and properties could be enhanced.
Description
Keywords
Maturação Cultivar, Cv. Cobrançosa Atividade antioxidante Composição fenólica
Citation
Sousa, Anabela; Malheiro, Ricardo; Casal, Susana; Bento, Albino; Pereira, J.A. (2014). A maturação como fator determinante na atividade antioxidante e composição fenólica em frutos da Cv. Cobrançosa = The maturation process as a determinant factor of the antioxidant activity and phenolic composition of Cv. Cobrancosa olive fruits. In 7th Iberian Congress of Agricultural Engineering and Horticultural Sciences. Madrid, p. 1866-1871. ISBN 978-84-695-9055-3
Publisher
Universidad Politecnica de Madrid