Efeito de infusões aquosas de diferentes espécies de plantas sobre o escurecimento da maçã e atividade da enzima tirosinase isolada de agaricus bisporus

Abstract

Fruits and vegetables have essential nutrient to human metabolism, therefore the deterioration these nutrients results on food quality loss. The nutrient loss associated to the enzymatic or no-enzymatic browning. The enzymatic browning occurs because of chemical alterations ensuring the microorganism deterioration activity or answering to phenolic compound oxidation into dark polymers and it caused by polyphenol oxidase (PPO) action, also known as tyrosinase. The phenolic substrate type and concentration directly affects enzymatic browning. The PPO in contact to oxygen, oxidize phenolic compounds (as Catecol), removing hydrogen from its branches, and as products has water and quinine, which can condense forming dark and insoluble polymers, such as Melanin. The aim of this work was to test the leaves aqueous infusions potential of Sida cordifolia L. (flannel weed), Mikania glomerata Spreng. (guaco), Cynara scolymus L. (artichoke), Bauhinia forficata Link (Brazilian orchid-tree), Camellia sinensis (L.) Kuntze (green tea) and Baccharis trimera (Less.) DC. (carqueja), on browning apple juice inhibition, on the Agaricus bisporus isolated tyrosinase activity inhabitation, and analyze the infusions interaction with copper metal which is present on this enzymatic activity site. Were evaluated the apple juice absorbance at 400 nm for 5 min incubation in the presence and absence of different infusions volumes. The tyrosinase activity was given by delta absorbance at 510 nm obtained on the last of one hour analysis. The infusions interactions with copper was done based on copper spectrum which has a 800 nm absorbance peak, and compared with EDTA interaction and ascorbic acid (Chelanting ready known). Was observed that greentea, Brazilian orchid-tree, carqueja and guaco were the most efficient to prevent the apple juice browning. The green-tea, guaco, carqueja and Brazilian orchid-tree demonstrated better tyrosine activity inhibition. The copper interaction was more clear to green-tea, guaco, Brazilian-orchid-tree and artichoke infusions. This study demonstrated that aqueous infusions of medicinal plants pres ent potential to act as food preservative agents via the enzyme tyrosinase inhibition.