Articles
Chitosan-based bio-coatings: preharvest treatment improves color quality of ‘Gala’ apple under sun exposure
Article number
1433_25
Pages
197 – 202
Language
English
Abstract
Apples are vulnerable to excessive solar radiation and high temperature, which would induce fruit damage.
In order to defend apples from sunburn injury during preharvest stage and improve the storability through long-term storage, a bio-coating with reflective TiO2 as active ingredient was developed and applied in the field by spray application.
The coating recipe was adapted based on elastic modulus of coating material, resulting in the final formulation with 1 wt% chitosan and 0.25 wt% glycerol as substrate material for better adhering of coating on the apple surface.
Eventually, chitosan (1 wt%)/glycerol (0.25 wt%)/rapeseed (1 wt%)/TiO2 (1 wt%) coating was applied on the apples, before T-stage and before harvest, on June 29 and August 30. In the commercial harvest window on September 21, fruit were harvested separately from the inner part of canopy and exposed part of canopy, capturing control and coated apples.
The four treatments were stored for 2- and 5-months storage in RA and CA conditions, resulting in eight variants.
Among fresh samples, enhanced L* and water content of coated apples, compared to control fruit, were found.
On November 27, coated samples showed higher L*, b*, fruit firmness, and water content, than those of control samples from in inner canopy part under CA condition.
On February 13, there were lower L* and b* and higher Fmax of coating samples than control samples from exposed growth location in the canopy under RA condition.
The coating treatment improved the brightness and water content of fresh samples as well as the brightness and b* variable of samples from internal growth location as measured on November 27, 2023. The coating treatment maintained the quality of apples during five-month storage as indicated by the fruit flesh firmness.
In order to defend apples from sunburn injury during preharvest stage and improve the storability through long-term storage, a bio-coating with reflective TiO2 as active ingredient was developed and applied in the field by spray application.
The coating recipe was adapted based on elastic modulus of coating material, resulting in the final formulation with 1 wt% chitosan and 0.25 wt% glycerol as substrate material for better adhering of coating on the apple surface.
Eventually, chitosan (1 wt%)/glycerol (0.25 wt%)/rapeseed (1 wt%)/TiO2 (1 wt%) coating was applied on the apples, before T-stage and before harvest, on June 29 and August 30. In the commercial harvest window on September 21, fruit were harvested separately from the inner part of canopy and exposed part of canopy, capturing control and coated apples.
The four treatments were stored for 2- and 5-months storage in RA and CA conditions, resulting in eight variants.
Among fresh samples, enhanced L* and water content of coated apples, compared to control fruit, were found.
On November 27, coated samples showed higher L*, b*, fruit firmness, and water content, than those of control samples from in inner canopy part under CA condition.
On February 13, there were lower L* and b* and higher Fmax of coating samples than control samples from exposed growth location in the canopy under RA condition.
The coating treatment improved the brightness and water content of fresh samples as well as the brightness and b* variable of samples from internal growth location as measured on November 27, 2023. The coating treatment maintained the quality of apples during five-month storage as indicated by the fruit flesh firmness.
Authors
C. Shi, A. Boini, W. Li, B. Morandi, M. Zude-Sasse
Keywords
apple, chitosan bio-coating, storage quality
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