Enzymatic carotenoid degradation and aroma formation in nectarines ( Prunus persica)

Abstract

C-13 norisoprenoids such as β-ionone, 3 hydroxy-β-ionone, and 3 hydroxy-5,6-epoxy-β-ionone are important carotenoid related aroma compounds in fruits. Apart from chemical degradation (photo-oxygenation, (auto)oxidation, thermal degradation), enzymatic cleavage is an important flavor formation pathway [ Enzell, C. (1985). Biodegradation of carotenoids – an important route to aroma compounds. Pure and Applied Chemistry, 57(5), 693–700; Winterhalter, P., & Rouseff, R. (Eds.). (2001). Carotenoid-derived aroma compounds. ACS symposium series 802, Washington, DC: American Chemical Society (ISBN 0-8412-3729-8)]. In nectarines, the content of carotenoid degradation products depends on the degree of maturity. In fully ripened fruit up to 40% of the aglycons are C-13 norisoprenoids [Aubert, C., Günata, Z., Ambid, C., & Baumes, R. (2003). Changes in physicochemical characteristics and volatile constituents of yellow- and white-fleshed nectarines during maturation and artificial ripening. Journal of Agriculture and Food Chemistry, 51(10), 3083–3091]. Regiospecific carotenoid cleavage enzymes have been shown to be involved in aroma formation in different plants and fruits [Bouvier, F., Suire, C., Mutterer, J., & Camara, B. (2003). Oxidative remodeling of chromoplast carotenoids: identification of the carotenoid dioxygenase CsCCD and CsZCD genes involved in crocus secondary metabolite biogenesis. Plant Cell, 15(1), 47–62; Fleischmann, P., Studer, K., & Winterhalter, P., (2002). Partial purification and kinetic characterization of a carotenoid cleavage enzyme from quince fruit ( Cydonia oblonga). Journal of Agriculture and Food Chemistry, 50(6), 1677–1680; Fleischmann, P., Watanabe, N., & Winterhalter, P., (2003). Enzymatic carotenoid cleavage in star fruit ( Averrhoa carambola). Phytochemistry, 63(2), 131–137; Schwartz, Qin & Zeevaart, 2001]. This paper describes the isolation and partial characterization of carotenoid cleavage enzymes in nectarines, isolated from ripe skin of commercially available fruit. The enzyme is characterized by its kinetic parameters ( v max, K m, time constant, temperature dependence, activation energy).