Articles
Use of optical coherence tomography (OCT) to detect and quantify changes during shrivel development in kiwifruit (Actinidia chinensis Planch.)
Article number
1396_21
Pages
149 – 158
Language
English
Abstract
Shrivel is a common postharvest storage quality problem in kiwifruit.
It is characterized by wrinkled skin and deformation of the fruit surface.
Shrivel is associated with water loss; generally, fruit is at risk of shrivel when approximately 4-5% of the at-harvest fresh weight has been lost during storage.
However, some fruit with high levels of water loss (>5%) may not show shrivel symptoms, suggesting that shrivel may be related to other fruit parameters including tissue structure.
Typically, shrivel symptoms are evaluated by imprecise, subjective visual assessment; comparatively, optical coherence tomography (OCT) could provide an objective method of evaluation.
Optical coherence tomography is a fast, non-invasive, real-time, in vivo technique that allows the acquisition of consistent and high-resolution two-dimensional (2D) and three-dimensional (3D) images of near-surface internal structures.
This technology has been used to evaluate the near-surface cellular structure of various fruit, including kiwifruit.
This research utilised OCT to visualise subsurface structural changes during shrivel development.
Kiwifruit from several cultivars were stored for up to 8 weeks at 1 and 10°C (55-75% RH) to induce a range of shrivel symptoms.
An OCT system with 820 nm central wavelength and 5.5 µm resolution was used to monitor changes in the near-surface structure of kiwifruit over the course of storage during shrivel progression.
Early indications confirm data derived from OCT images such as periderm thickness, and sub-peridermal cell attributes such as volume, number and shape are amenable to analysis and can be tested as predictors of subsequent shrivel risk.
Initial observation of Gold3 and Gold9 raw OCT images indicated changes in the near-surface cellular layers with shrivel advancement; cell layers appeared uniform in fruit without shrivel compared to more compact cell layers in severely shrivelled fruit.
These results suggest that changes in the microstructure of fruit beneath the skin may be associated with the development of shrivel and have potential to be detected by OCT imaging technology.
It is characterized by wrinkled skin and deformation of the fruit surface.
Shrivel is associated with water loss; generally, fruit is at risk of shrivel when approximately 4-5% of the at-harvest fresh weight has been lost during storage.
However, some fruit with high levels of water loss (>5%) may not show shrivel symptoms, suggesting that shrivel may be related to other fruit parameters including tissue structure.
Typically, shrivel symptoms are evaluated by imprecise, subjective visual assessment; comparatively, optical coherence tomography (OCT) could provide an objective method of evaluation.
Optical coherence tomography is a fast, non-invasive, real-time, in vivo technique that allows the acquisition of consistent and high-resolution two-dimensional (2D) and three-dimensional (3D) images of near-surface internal structures.
This technology has been used to evaluate the near-surface cellular structure of various fruit, including kiwifruit.
This research utilised OCT to visualise subsurface structural changes during shrivel development.
Kiwifruit from several cultivars were stored for up to 8 weeks at 1 and 10°C (55-75% RH) to induce a range of shrivel symptoms.
An OCT system with 820 nm central wavelength and 5.5 µm resolution was used to monitor changes in the near-surface structure of kiwifruit over the course of storage during shrivel progression.
Early indications confirm data derived from OCT images such as periderm thickness, and sub-peridermal cell attributes such as volume, number and shape are amenable to analysis and can be tested as predictors of subsequent shrivel risk.
Initial observation of Gold3 and Gold9 raw OCT images indicated changes in the near-surface cellular layers with shrivel advancement; cell layers appeared uniform in fruit without shrivel compared to more compact cell layers in severely shrivelled fruit.
These results suggest that changes in the microstructure of fruit beneath the skin may be associated with the development of shrivel and have potential to be detected by OCT imaging technology.
Authors
J.M. Longuet-Higgins, M. Li, M.A. Urbańska, S.A. Rivera, J.A. Heyes, A.R. East
Keywords
Actinidia, postharvest, water loss, non-destructive, image analysis, cellular structure, disorder
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