Effect of Postharvest Methyl Jasmonate Treatment on Early-Matured “Hass” Avocado Fruit Exocarp Colour Development during Ripening

Kingsly Shikwambana,Nhlanhla Mathaba,Tieho P Mafeo

doi:10.4236/as.2021.128056

Kingsly Shikwambana, Nhlanhla Mathaba + Show 1 more

Open Access

https://doi.org/10.4236/as.2021.128056

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Abstract

Poor exocarp colour development is a common postharvest problem for early harvested “Hass” avocado fruit during ripening, which affects fruit quality and consumer preference. Therefore, measures to improve “Hass” avocado fruit colour developments are of great importance in the industry. This study investigated the effectiveness of postharvest methyl jasmonate treatment to improve early matured “Hass” avocado fruit exocarp colour during ripening. The results showed that T1 (10 μmol∙L−1) and T2 (100 μmol∙L−1) MeJA treatment increased visual colour, and decreased objective colour parameters (L*, C* and h˚) during ripening when compared with control fruit. Moreover, MeJA treated “Hass” avocado fruits had lower total chlorophyll content and higher total anthocyanin and cyanidin-3-O-glucoside concentration during ripening. In conclusion, “Hass” avocado fruit post-harvest treated with either T1 (10 μmol∙L−1) or T2 (100 μmol∙L−1) MeJA concentration improved exocarp quality attributes such as colour parameters (L*, C* h˚ and visual colour) and pigments (total anthocyanin and cyanidin-3-O-glucoside) during ripening, therefore, can be recommended for avocado fruit.

Highlights

This study investigated the effectiveness of postharvest methyl jasmonate treatment to improve early matured “Hass” avocado fruit exocarp colour during ripening
There was an increase in exocarp visual colour for T1 (10 μmol∙L−1) and T2 (100 μmol∙L−1) methyl Jasmonate (MeJA) treatment when compared with control fruit (Figure 1(a))
Objective exocarp colour parameters (L*, C* and h) of MeJA treated fruit were lower than those of control fruit on days 4 and 6 at 25 ̊C. Such results indicated that MeJA treatment stimulated exocarp purple colour development for “Hass” avocado fruit during ripening. These results could be attributed to the role of MeJA in regulating anthocyanin biosynthesis and implied that an improved exocarp colour development was enhanced by MeJA treatment when compared with control fruit

Summary

Introduction

Mathaba et al [2] found that “Hass” avocado fruit harvested at early maturity tended to show poor exocarp colour development during ripening. “Hass” avocado fruit changes exocarp colour from green to purple and eventually black, mainly owing to chlorophyll degradation and synthesis and anthocyanin accumulation [1] [3]. In “Hass” avocado fruit exocarp, cyanidin-3O-glucoside is the most abundant specific anthocyanin pigment during ripening [1]. According to Ashton et al [4], cyanidin-3-O-glucoside is an anthocyanin compound responsible for the purple and black colour development during the ripening of “Hass” avocado fruit. There is an interest in exploring postharvest treatment which triggers the enhancement of anthocyanin synthesis and accumulation, leading to improved early matured “Hass” fruit exocarp colour development during ripening

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