ABSTRACT

This study was conducted to identify reliable science-based maturity indices for ‘Lamb Hass’ avocado fruit and evaluate the effect of harvest maturity on the fruit postharvest performance. Fruits were harvested from outside and inside canopy positions at early and mid-season for quality assessment. The results showed that the canopy position had a highly significant effect (p < .001) on all maturity parameters: dry matter (DM) content, moisture content (MC) and oil content (OC). The outside canopy fruit were more mature (30% DM, 70% MC, 14.9% OC) than those harvested from the inside canopy (28.9% DM, 71.1% MC, 11.75% OC) at minimum maturity. However, fruit DM and MC did not differ significantly (p > .05) between the early and mid-season fruit, whilst significant differences in OC were found between the two harvesting stages. In both harvesting stages, the canopy positions did not affect the rate of fruit mass loss. Nonetheless, the overall analysis showed that early season fruit had a significantly (p < .001) higher fruit mass loss rate than the mid-season fruit. Notably, fruit maturity did not have a significant effect (p > .05) on the fruit softening rate as insignificant differences between the two harvesting stages were observed. In both the harvesting stages, inside canopy fruit were characterized by a higher concentration of mannoheptulose and perseitol than the outside canopy fruit. The early and mid-season fruit also differed significantly (p < .05) in phenolic content; with the mid-season fruit having a high phenolic content (2.7 µm/g) than the early season fruit (1.8 µm/g), suggesting the possibility of increased mesocarp discolouration with the advancement in maturity. These findings will be a valuable tool to assist growers in assessing fruit readiness for harvest and understanding the influence of maturity on the fruit postharvest behavior.

摘要

本研究旨在确定“Lamb Hass”鳄梨果实的可靠的基于科学的成熟度指数，并评估收获成熟度对果实收获后性能的影响。在季节早期和中期从树冠位置的外部和内部收获水果以进行质量评估。结果表明，树冠位置对所有成熟度参数都有非常显着的影响（p < .001）：干物质（DM）含量、水分含量（MC）和油含量（OC）。在最低成熟度时，外冠果实（30% DM、70% MC、14.9% OC）比从内部冠层收获的果实（28.9% DM、71.1% MC、11.75% OC）更成熟。然而，水果 DM 和 MC 没有显着差异（p> .05)，而在两个收获阶段之间发现了 OC 的显着差异。在两个收获阶段，冠层位置不影响果实质量损失率。尽管如此，总体分析表明，早季果实的果实质量损失率显着（p < .001）高于中季果实。值得注意的是，果实成熟度对果实软化率没有显着影响 ( p > .05)，因为观察到两个收获阶段之间的差异不显着。在两个收获阶段，内部冠层果实的特征是甘露庚酮糖和甘露糖醇的浓度高于外部冠层果实。早、中季果实也有显着差异（p< .05) 酚含量；中果皮的酚类含量（2.7 µm/g）比早熟果（1.8 µm/g）高，这表明随着成熟期的推进，中果皮变色增加的可能性。这些发现将成为帮助种植者评估果实收获准备情况和了解成熟度对果实收获后行为的影响的宝贵工具。