Effects of temperature and gas concentration on the respiration of fruits and vegetables.
Shiina, T.; Yamauchi, H.; Haruenkit, R.;
Postharvest Horticulture Series - Department of Pomology, University of California Year: 1997 Issue: No. 15 Pages: 71-76 Ref: 7 ref.
1997
บทคัดย่อ
A system for analysing the effects of temperature, O2, CO2 and C2H4 concentration on the respiration of fruits and vegetables was developed. The flow system developed consists of a gas mixture generator, acrylic chambers for products, gas samplers, a gas chromatograph and a data processor. Flow rates of N2, O2, CO2 and C2H4 (balanced with N2) were controlled by 4 mass flow controllers to obtain the desired gas mixture. Rates of O2 uptake and CO2 output were measured under both normal and controlled atmosphere (CA) or modified atmosphere (MA) conditions by analysing the inlet and outlet gas concentrations. Relative respiration rates (Rr) were obtained by dividing the respiration rate under CA conditions by that in air. Twelve commodities (sweetcorn, young vegetable soybean, asparagus, broccoli, cabbages, Brussels sprouts, Chinese cabbages, spinach, lettuces, red chicory, potatoes and Japanese apricots) were used in the study. Rr declined in all commodities when the O2 concentration was lowered, b
ut the extent of the decline varied among commodities. In most commodities, Rr was lower at higher temperatures. Extinction point, the lowest O2 concentration at which anaerobic respiration ceases, was measured by the evolution of acetaldehyde and ethanol. For sweetcorn, the extinction point was comparatively high at a high temperature. It is suggested that the inner O2 concentration of the respiring product is lower at a high temperature under the same ambient O2 concentration because under higher temperature the solubility of O2 is lower and the consumption rate is higher. The results suggest that the O2 concentration inside the product directly affects respiratory activity.