Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

Tomato (Solanum lycopersicum) is one of the most consumed fruit in the world as fresh or processed products. Its chemical composition is influenced by genetic factors, stage of development, climatic conditions, soil and cultivation systems, such as organic and conventional. Plant resistance to pathogens are associated to the phenylpropanoid pathway where stand out the enzyme phenylalanine-ammonia-lyase. The Oxido-reductase enzymes (superoxide dismutase, polyphenoloxidase, catalase and peroxidase) also contribute to plant defense. The study evaluated the effect of the crop management (conventional and organic) on the activity of the enzymes related to defense mechanisms in Italian variety tomatoes available in the market. Six Representative sampling were carried out in supermarkets of Rio Grande – RS. Organic cultivation of the samples were guaranteed by MAPA certification label. The uniformity of the maturation stage of the samples was established by color, pH and sugar/acid ratio and lyophilization. The activities of the enzymes peroxidase (PO), polyphenoloxidase (PPO) and phenylalanine-ammonia-lyase (PAL) were determined in saline extract (NaCl 0.9%) and catalase (CAT) with 0.1 M phosphate buffer pH 5, 0 and expressed as specific activity. Italian tomatoes from organic cultivation showed higher activities of the enzymes PO (76.0 U. mg-1 protein), PPO (363.6 U. mg-1 protein) and PAL (14.1 U. mg-1 protein). Therefore, it can be inferred that this variety cultivated under organic system manifests its defense potential against abiotic and possibly biotic damage with greater intensity. This fact suggests the possibility of these enzymes being used for the traceability and certification of this fruit.