Browsing by Author "Vargas, Helion"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Application of photoacoustic spectroscopy in monitoring emission of C2H4 and CO2 in passion fruit stored under different atmospheres.
    (2012) Correa, Savio Figueira; Oliveira, J. G.; Santos, W. C.; Souza, A. F.; Vargas, Helion; Silva, M. G.
    The present work shows the application of the photoacoustic spectrometer in the monitoring of the ethylene emission rate in passion fruit submitted to different types of atmosphere storage. Three types of modified atmosphere were applied: 1) 100% N2 and 0% O2 (MA1), 2) 97% N2 and 3% O2 (MA2) and 3) 94% N2 and 6% O2 (MA3). The respiratory rate and parameters of the skin color as CIE a, b and angle hue were monitored and correlated with the ethylene emission rate. The loss of mass was also evaluated. Results indicated that atmospheres with oxygen concentrations below 3% cause fruit damage, evident as fermentation and presence of fungus in the skin, while 6% oxygen led to a 2 day increased in shelf life.
  • No Thumbnail Available
    Item
    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.
    (2011) Corrêa, Savio Figueira; Mota, Leonardo; Paiva, Luisa Brito; Couto, Flávio Mota do; Silva, Marcelo Gomes da; Oliveira, Jurandi Gonçalves de; Sthel, Marcelo Silva; Vargas, Helion; Miklós, András
    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.
  • No Thumbnail Available
    Item
    Influence of hydrothermal treatments on papaya fruit (Carica papaya L.).
    (2012) Corrêa, Savio Figueira; Silva, Marcelo Gomes da; Pereira, Talita; Almeida Júnior, Paulo Sérgio Gomes de; Vargas, Helion; Oliveira, Jurandi Gonçalves de; Berili, Sávio Silva
    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.