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Abstract(s)
Recentemente, com a evolução do mercado do chá e devido à crescente procura pela novidade por parte dos consumidores, as empresas de plantas têm vindo a desenvolver novos produtos de valor acrescentado, com características exclusivas. Entre estes produtos, os lotes de reserva de plantas aromáticas, surgem como uma seleção de partes específicas de plantas, preparadas através de técnicas de colheita distintas, que lhes confere características organoléticas singulares.
No presente estudo foram avaliados quatro espécies de plantas amplamente consumidas em Portugal, entre elas a Mentha spicata L., Cymbopogon citratus (DC.) Stapf, Aloysia citriodora (L’Herit.) Britton, e Thymus × citriodorus L., de forma a explorar as diferenças entre infusões preparadas a partir dos lotes normais e reserva, no que respeita à sua composição fenólica e às suas propriedades antioxidantes. As infusões obtidas pelos lotes reserva de M. spicata, C. citratus e A. citriodora revelaram uma maior concentração em compostos fenólicos do que os preparados através dos lotes normais. Por outro lado, a infusão obtida através do lote normal de T. citriodorus apresentou maiores quantidades de ácidos fenólicos do que o lote reserva, no entanto, a quantidade de flavonoides totais e compostos fenólicos não foi significativamente diferente do lote reserva.
Ambos os lotes de M. spicata apresentam o ácido rosmarínico como sendo o composto fenólico maioritário, no entanto o lote reserva foi o que apresentou maior teor em compostos fenólicos totais. C. citratus revelou uma prevalência de flavonoides, com uma elevada contribuição de luteolina 2”-O-deoxi-hexosil-6-C-glucósido, mas o composto mais abundante foi o ácido 5-O-cafeoilquínico em ambos os lotes. Relativamente à A. citriodora a luteolina-7-O-diglucurónido e verbascósido foram os compostos maioritários identificados. Em T. citriodorus, em ambos os lotes registou-se uma prevalência de ácidos fenólicos, sendo o ácido rosmarínico o mais abundante, seguido do ácido litospérmico A e de um hexósido de ácido rosmarínico.
Em termos de atividade antioxidante, as diferenças entre lotes foram mais evidentes nas infusões de C. citratus e M. spicata do que nas restantes infusões, sendo o lote reserva, aquele que apresentou maior atividade antioxidante. Em geral, a atividade antioxidante das infusões preparadas a partir de diferentes lotes de plantas está correlacionada positivamente com a sua composição fenólica.
Recently, with the evolution of the tea market, given the increasing consumers demand for novelty, tea companies have been presenting new added value products with alternative traits. Among these products, the reserve lots of aromatic plants arise as a selection of specific parts of the plants, prepared through distinct harvesting techniques that confer them singular organoleptic characteristics. In the present study, four widely consumed specimens in Portugal, Mentha spicata L., Cymbopogon citratus (DC.) Stapf, Aloysia citriodora (L’Herit.) Britton, and Thymus × citriodorus L. were assessed to explore the differences between infusions prepared from their standard and reserve lots, in what concerns the phenolic composition and related antioxidant properties. The infusions obtained from M. spicata, C. citratus and A. citriodora reserve lots revealed higher concentration in phenolic compounds than those prepared from the respective standard lots. Otherwise, the infusion of T. citriodorus standard lot presented higher amounts of phenolic acids than the reserve lot, nonetheless, total flavonoids and phenolic compounds were not significantly different between both lots. The two types of M. spicata lots presented rosmarinic acid as the most abundant phenolic compound, but the reserve lot had the highest total phenolic compounds content. C. citratus revealed a prevalence of flavonoids, with the highest contribution of luteolin 2”-O-deoxyhexosyl-6-C-glucoside, but the most abundant compound was 5-O-caffeoylquinic acid in both lots. Regarding A. citriodora, luteolin-7-O-diglucuronide and verbascoside were the major compounds identified. In T. citriodorus, both lots revealed the prevalence of phenolic acids, with rosmarinic acid as the most abundant, followed by lithospermic acid A and rosmarinic acid hexoside. In terms of antioxidant activity, the differences between both lots were more noticeable in C. citratus and M. spicata than in the other plants infusions, with the reserve lot presenting the highest activity. In general, the antioxidant activity of the infusions prepared from the different lots of the plants was positively correlated to their phenolic composition.
Recently, with the evolution of the tea market, given the increasing consumers demand for novelty, tea companies have been presenting new added value products with alternative traits. Among these products, the reserve lots of aromatic plants arise as a selection of specific parts of the plants, prepared through distinct harvesting techniques that confer them singular organoleptic characteristics. In the present study, four widely consumed specimens in Portugal, Mentha spicata L., Cymbopogon citratus (DC.) Stapf, Aloysia citriodora (L’Herit.) Britton, and Thymus × citriodorus L. were assessed to explore the differences between infusions prepared from their standard and reserve lots, in what concerns the phenolic composition and related antioxidant properties. The infusions obtained from M. spicata, C. citratus and A. citriodora reserve lots revealed higher concentration in phenolic compounds than those prepared from the respective standard lots. Otherwise, the infusion of T. citriodorus standard lot presented higher amounts of phenolic acids than the reserve lot, nonetheless, total flavonoids and phenolic compounds were not significantly different between both lots. The two types of M. spicata lots presented rosmarinic acid as the most abundant phenolic compound, but the reserve lot had the highest total phenolic compounds content. C. citratus revealed a prevalence of flavonoids, with the highest contribution of luteolin 2”-O-deoxyhexosyl-6-C-glucoside, but the most abundant compound was 5-O-caffeoylquinic acid in both lots. Regarding A. citriodora, luteolin-7-O-diglucuronide and verbascoside were the major compounds identified. In T. citriodorus, both lots revealed the prevalence of phenolic acids, with rosmarinic acid as the most abundant, followed by lithospermic acid A and rosmarinic acid hexoside. In terms of antioxidant activity, the differences between both lots were more noticeable in C. citratus and M. spicata than in the other plants infusions, with the reserve lot presenting the highest activity. In general, the antioxidant activity of the infusions prepared from the different lots of the plants was positively correlated to their phenolic composition.
Description
Mestrado em cooperação com a Universidade de Salamanca
Keywords
Tomilho-limão Hortelã-vulgar Limonete Erva-príncipe