Biochemical characterization of the flavedo of heat-treated Valencia orange during postharvest cold storage

PEROTTI, VALERIA; MORENO, ALEJANDRA; TRIPODI, KARINA; DEL VECCHIO, HERNÁN; MEIER, GUILLERMO; BELLO, FERNANDO; COCCO, MARIÁNGELES; VÁZQUEZ, DANIEL; PODESTÁ, FLORENCIO

POSTHARVEST BIOLOGY AND TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 99 p. 80 - 87

0925-5214

Heat treatment is a powerful and eco-friendly method to prevent Penicillium infection in citrus fruit during the postharvest. Several studies have been dedicated to investigate the general chemical changes thatjustify the immediate reaction responsible for the induced tolerance; but just how primary metabolismand enzymology are affected by heat treatment and along a prolonged cold storage is still unclear. Inthis work, the main enzymes ofcarbon metabolism ofValencia orange flavedo were analyzed during thepostharvest period after a heat treatment (HT) of 48 h at 37 ◦C. Enzymatic activity measurements indicated thatthe NADPH producingenzymes glucose 6-phosphate dehydrogenase and non-phosphorylatingglyceraldehyde 3-phosphate dehydrogenase have lower levels in HT fruit. In parallel, a higher synthesis of sucrose from organic acids was observed in HT epicarp. Sucrose-phosphate synthase would havean important role in sucrose accumulation. The pathway of carbon through glycolysis was affected bycold storage, independently of HT, in a way that it favors the ATP-dependent phosphofructokinase overthe PPi-dependent homologous enzyme and the use of phosphoenolpyruvate (PEP) by PEP carboxylase instead of pyruvate kinase. Similarly, phenylpropanoid compounds did not show major changes inresponse to HT, although some ofthem showed a marked descent along the cold storage. Proteomic studies revealed alterations in the abundance of ascorbate peroxidase, two germin-like proteins and smallHSPs, completing the description ofthe main metabolic changes in this tissue.