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• References1. L.Hooper, A. Cassidy, A review of the health care potential of bioactive compounds. J Sci Food Agri., 86 (2006) 1805–1813.2. Y.T.Szeto, T.C.Kwok, I.F.Benzie. Effects of a long-term vegetarian diet on biomarkers of antioxidant status and cardiovascular disease risk, Nutrition, 20 (2004) 863-8663. , J.K. Brecht., M.E. Slatveit, S.T. Tacoltt, K.R.Schneider, K.Felkey, J.A. Bartz, Fresh-cut vegetables and fruits. Hortic Rev., 30(2004) 185-250.4. M.E. Saltveit, Physical physiological changes in minimally processed fruits and vegetables. In phytochemistry of fruit and vegetables; Tomas-Barberan, F.A., Robins, R.J., Eds.; Oxford University Press: London, 1997.
• 5. F.A. Tomas-Barberan, M.Gill, M.Castaner, F. Artes, M.E. Saltveit, Effect of selected browning inhibitors on phenolic metabolism in stem tissue of harvested lettuce. J Agri Food Chem., 45(1997) 583-589.6. M.E. Saltveit, Chilling injury is reduced in cucumber and rice seedlings and in tomato pericarp discs by heat-shocks applied after chilling. Postharvest Biol Technol 21 (2000) 169–177.
• 7. A.G. Ponce, C.E. Del Valle, S.I. Rural, Natural essential oils as reducing agents of peroxidase activity in leafy vegetables. Lebensm-Wiss Technol, 37(2004) 199-204.8. E. Degl`Innocenti,.A. Pardossi, F.Tattini, L. Guidi, Phenolic compounds and antioxidant power in minimally processed salad.J. Food Biochem. 32(2008) 642-653.9- A.Altunkaya, V.Gökmen, Effect of various inhibitors on enzymatic browning, phenol content and total antioxidant activity of fresh lettuce (L.sativa). Food Chem. 107(2008) 1173-1179. 10. M.A., Bradford, A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem., 72 (1976) 248–254.
• 10. H. Lineweaver, D. Burk, The determination of enzyme dissociation constants. J Am Chem Soci., 56(1934) 658–666.11- M.A.Amerine, C.S. Ough, Methods for analysis of musts and wines, Wiley, Newyork. 1980.12- U.Gawlik-Dziki, U.Zotek, M. O. Ewieca,. Characterization of polyphenol oxidase from butter lettuce (Lactuca sativa var. capitata L.), Food Chem.. 107(2008) 129–135.13. R.K.: Scopes, Protein Purification: Principles and Practice, Springer- Verlag, Berlin, Germany 1987.
• 14. C.T. Mant, R.S. Hodges, High Peformance Liquid Chromatography of Peptides and Proteins: Seperation, Analysis and Conformation, CRC Press, Boca Raton, FL, USA, .1991.
• 15. K.M. Mdluli, Partial purification and characterisation of polyphenol oxidase and peroxidase from marula fruit (Sclerocarya birrea subsp. Caffra), Food Chem., 92(2005) 311–323.16. S. Dogan, M.Dogan, Determination of kinetic properties of polyphenol oxidase from Thymus (Thymus longicaulis subsp. Chaubardii var. chaubardii). Food Chem. 88(2004) 69–77.17. F. Aylard, D. R. Haisman, Oxidation systems in fruits and vegetables.-their relation to the quality of preserved products. Anal. Biochem., 72(1969) 248-25818. D. Kavrayan, T. Aydemir, Partial purification and characterization of polyphenoloxidase from peppermint (Mentha piperita). Food Chem., 74(2001) 147–154.19. S. V. Jovanovic, , S. Steenken, , M.Tosic, , B. Marjanovic, M. G. Simic, Flavonoids as antioxidants. J. Am. Chem.Soci. 116 (1994) 4846–4851.20.C. Kandaswami, J.R.Middleton. Free radical scavenging and antioxidant activity of plant flavonoids. Adv. Exp. Med.Biol. 366 (1994),351-376.21. N. J. Miller, C. Rice-Evans, The relative contributions of ascorbic acid and phenolic antioxidants to the total antioxidant activity of orange and apple fruit juices and blackcurrant drink. Food Chem., 60 (1997) 331–337.22. J. Darkwa, C.Mundoma, , R. H. Simoti, Antioxidant chemistry reactivity and oxidation of DL cysteine by some common oxidants. J Chem Soci.-Faraday Transac., 94 (1998) 1971–1978.23. F. C. Richard-Forget, P. M. Goupy, J. J. Nicolas, Cysteine as an inhibitor of enzymatic browning 2. Kinetic studies. J Agric Food Chem., 40 (1992) 2108–2113.