LAUSR

Abstract This study aimed at evaluating the effect of organic and conventional farming systems on enzymatic profiles of tomatoes so as to find a biomarker for their safe traceability and certification. Three tomato varieties (Khaki, Italian and Cherry), officially certificated and sold in fruit shops, were collected in different seasons. The fruits of each variety were standardized in analytical samples in relation to their ripeness indicators (color, sugar/acidity rate). Assays used for determining enzymatic activities were previously standardized to invertases (INV), polygalacturonases (PG), peroxidases (PO), polyphenoloxidases (PPO), catalases (CAT) and phenylalanine ammonia lyase (PAL). Enzymatic activities were correlated with the farming systems by the Principal Component Analysis (PCA). Enzymatic activities of PO, PPO, CAT and PAL proved to be useful for tomato certification and traceability, since their correlation was above 0.9. The statistical analysis confirmed that PO and CAT activities were the most promising to find a model of response to the farming system. Enzymatic profiles of both Italian and Cherry varieties were the most affected by the farming system.