Study of the respiratory pattern and application of ethylene on postharvest ripening of chilli (Capsicum annum var. MI-2)

Abstract

Chilli (Capsicum annum var.MI-2) pods harvested at different stages of maturity ranging from light green to full red were used to study the respiration changes at 15.5 °C and 83 % RH in a closed system. Respiration rates of chilli from light green to full red stage ranged between 12.7-24.2 mgC02/kg/h. The rate of respiration was low (12.7 mgC02/kg/h) at light green stage and increased with maturity reaching a peak of 24.2 mgC02/kg/h at the stage where a distinct colour change occurs. In the ripening process, at first respiration rate decreases. Then later as the red colour develops, the respiration is shown to increase. Ethylene was present in the pods between 3.2-4.3 ppm. However, there was no ethylene peak observed with the maturity. Fruits were allowed to ripen at ambient conditions (32 ± 2 °C and 37 % RH) with 0, 100, 200, 300, and 400 ppm ethylene concentrations. Observations were made on colour development of pods during storage. Ethylene treatment had no significant effect on colour development of chilli harvested at both mature green and colour break stages of maturity. Results provided that Capsicum annum var. MI-2 belongs to non-climacteric group of fruits.