Influence of hydrothermal treatments on papaya fruit (Carica papaya L.).

Four postharvest hydrothermal treatments were applied on papaya fruit (Carica papaya L.) ?Golden? and the stress stimulated by the treatments was monitored by the ethylene (C2H4), carbon dioxide (CO2) emission rates and fruit quality. The postharvest hydrothermal treatments consisted of submerging alternately the fruit into two water baths, the first one with water at a temperature of 49?C and the second at 12?C. An increase in the emission rates of both gaseous species (C2H4 and CO2) was observed as a response to the stress. Typical quality parameters as pulp firmness, pH, titratable acidity and total soluble solids were simultaneously determined and correlated with the gases emitted from the fruits

Effects of ozone exposure on ?golden? papaya fruit by photoacoustic phase-resolved method : physiological changes associated with carbon dioxide and ethylene emission rates during ripening.

This work addresses the effects of ozone activity on the physiology of ?Golden? papaya fruit. Depth profile analysis of double-layer biological samples was accomplished using the phase-resolved photoacoustic spectroscopy. The feasibility of the method was demonstrated by singling out the spectra of the cuticle and the pigment layers of papaya fruit. The same approach was used to monitor changes occurring on the fruit during ripening when exposed to ozone. In addition, one has performed real time studies of fluorescence parameters and the emission rates of carbon dioxide and ethylene. Finally, the amount of pigments and the changes in waxy cuticle have been monitored. Results indicate that a fruit deliberately subjected to ozone at a level of 6 ppmv underwent ripening sooner (at least 24-48 h) than a fruit stored at ambient conditions. Moreover, ozone caused a reduction in the maximum quantum yield of photosynthetic apparatus located within the skin of papaya fruit. VC 2011 American Institute of Physics