ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Determination of the low oxygen limit for several commercial apple cultivars by respiratory quotient breakpoint.

Gran, C. D.; Beaudry, R. M.;

Postharvest Biology and Technology Year: 1993 Vol: 3 Issue: 3 Pages: 259-267 Ref: 19 ref.

1993

บทคัดย่อ

Low oxygen limits for apple fruits, cultivars Empire, Red Fuji, Golden Delicious, Ida Red, Jonathan, Law Rome, McIntosh (strain MacSpur), Northern Spy and Red Delicious, were determined using modified atmosphere packaging (MAP) techniques. Fruits were sealed in low density polyethylene (LDPE) packages and placed at 0 deg C until steady-state respiration was reached. Steady state O2 and CO2 partial pressures were varied by altering package thickness, package surface area and the total fruit weight within the package. Based on measured permeabilities of the LDPE packages to O2 and CO2, package partial pressures were used to determine the gas flux for O2 and CO2 for each package, with gas flux rates representing respiratory rates. The effect of O2 partial pressure on O2 uptake, CO2 production and the respiratory quotient (RQ) was then determined. As the O2 partial pressure decreased to approx. 2 kPa, RQ remained relatively constant. A marked increase in the RQ (the RQ breakpoint) occurred below 2 k Pa O2, which was associated with elevated ethanol concentrations. The low O2 tolerance limit was then estimated for each cultivar as the O2 level at the RQ breakpoint; these values ranged from 0.7 kPa O2 for cv. Red Delicious and 0.8 kPa for cv. Law Rome to approx. 1.9 kPa for cv. McIntosh.