Effect of ripening temperature on early-season 'Hass' avocado fruit exocarp colour development and pigmentation during ripening

Abstract

South African ‘Hass’ avocado fruit harvested early season are vulnerable to colour desynchronisation with softening during ripening, reducing their international and local market aesthetic value. So far, research has proven that ‘Hass’ avocado fruit exocarp colour desynchronization is an early season conundrum. However, there is insufficient literature on underlying factors causing exocarp colour desynchronisation. Therefore, the study aimed to investigate the ripening temperature effect on early season ‘Hass’ avocado fruit exocarp colour development and pigments during ripening. Early season ‘Hass’ avocado fruit were stored at 5.5 °C for 28 days thereafter, ripened at 16, 21 and 25 °C and evaluated for firmness, visual and objective colour (L*, C* and h°), total chlorophyll and anthocyanin content. The results showed that the visual colour of fruit ripened at 25 °C was significantly higher compared to 21 and 16 °C after 2 and 4 ripening days. This study found that ripening temperature had no significant influence on chlorophyll degradation. However, fruit ripened at 25 °C accumulated significantly higher exocarp anthocyanin concentration compared to lower ripening temperatures. In conclusion, ripening early season ‘Hass’ avocado fruit at 25 °C resulted in improved exocarp colour development and anthocyanin accumulation.