Gas Permeability of CO2, O2 and N2 through the Peel of Satsuma Mandarin (Citrus unshiu Marc.)
1977 Volume 46 Issue 3 Pages 389-394
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1977 Volume 46 Issue 3 Pages 389-394
Even though there is a relation between the physical properties of the peel of satsuma mandarin and preservability of the fruit during the distribution process, few papers have been reported on the gas permeability through the peel and other properties.
In this paper, we presented the steady state and non-steady state methods to measure the permeability constants of CO2, O2 and N2 through the peel of satsuma mandarin. These methods were improved ones on the sweep gas method which was used to measure the gas permeability of packaging film. Furthermore some observations of the respiratory characteristics of the peel were performed in order to use in calculating the permeability constants.
1. Permeability constant of CO2 through the peel was measured by the steady state method.
(1) 92 percent of CO2 production by the peel was exhausted from the albedo side. The amounts were 1.43×10-2[cm3/cm2/hr] for the fruit collected on Nov. 14 and 2.41×10-2[cm3/cm2/hr] on Dec. 15 in 1975 respectively (Fig. 3, Fig. 4).
(2) CO2 concentration in the atmosphere enclosed with the hemispherical peel and plastic plate increased gradually and then reached its equilibrium state in more than ten hours. Equilibrium concentrations of CO2 were 4.7 percent for the fruit collected on Nov. 14 and 8.0 percent on Dec. 15 respectively (Fig. 5).
(3) By substituting these values into equation (1), the permeability constants of CO2 through the peel of satsuma mandarin were obtained to be 11.3×10-4[cm3/cm/hr/cmHg] for the fruit collected on Nov. 14 and 11.5×10-4[cm3/cm/hr/cmHg] on Dec. 15 respectively (Tab. 1).
2. In measuring by the non-steady state method, permeability constants of CO2, O2 and N2 through the peel were 8.9×10-4, 5.2×10-4 and 4.7×10-4[cm3/cm/hr/cm Hg] in order (Tab. 1).
3. The difference of the magnitude of the permeability constants among three gases was proven by measuring the gauge pressure in the atmosphere enclosed with the hemispherical peel and plastic plate when both the flavedo and albedo sides of the peel were filled with different pure gas (Fig. 8).
