2.6. Measurement of respiration rate
The effect of coating on CO2 was measured by analyzing the
headspace gas composition. Typically, apple slices (100 g), coated or
noncoated, were stored in a 100 mL tight-sealed glass container at 25 °C
for 24 h. Headspace samples were withdrawn at various time intervals
and analyzed for CO2 by gas chromatography (Hitachi Model 163, USA),
equipped with a thermal conductivity detector and a CTR 1 column
(Alltech Associates, Inc., USA). Helium was the carrier gas at 35 mL/min.
The injector was 50 °C, detector 100 °C, and the column was 50 °C. All
respiration rate measurements were done in three replicates.