Cardoon (Cynara cardunculus L.) flowers as sources of phenolic compounds with high biological potential
Artigo de Conferência
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resumo
Cardoon (Cynara cardunculus L.) belongs to Asteraceae Dumortier family and its flower aqueous
extracts have been used for centuries as coagulants in the production of traditional ewes’ milk
cheeses, obtaining specific characteristics of textures and flavour [1]. The use of cardoon flowers
(Cynara spp.) as a coagulant is obligatory for many Portuguese and Spanish cheeses due to their
high content of aspartic proteases and high milk-clotting activity [1,2]. Cardoon flowers from
specific genetic resources distributed in Serra da Estrela region have been studied and approved
for the application as cheese coagulant in order to obtain cheeses with higher quality and
confirming the authenticity of cheeses, simultaneously [3], with consequently increase of the
bioactive properties of these products. Therefore, it is very important to know the phenolic
composition and the bioactive properties of C. cardunculus. Three different cardoon genotypes
from Serra da Estrela region were used to prepare hydromethanolic extracts that were further
characterized in terms of phenolic compounds and bioactivities. Genotype, components of the
flowers and harvesting time proved to have a great influence in the content of phenolic
compounds (the major compounds found were apigenin and caffeoylquinic acid derivatives). For
the antioxidant activity, the stigma and the fibrous white inner presented the lowest EC50 values.
Regarding antibacterial assays, all the samples presented activity against Gram-positive bacteria,
mainly Listeria monocytogenes. The presence of phenolic acids and non-anthocyanin flavonoids
showed high correlations with antioxidant/antibacterial activities. Besides its proteolytic action for
milk clotting process, cardoon inflorescences show the potential to be sources of bioactive
compounds in PDO cheeses. To obtain simultaneously proteolytic action, high phenolic content
and high biological activity, these results could help defining the best combination of harvesting
procedure time of conservation and processing of cardoon flowers.
