Influence of ethylene and ethephon treatments on the peel color and carotenoids of Gannan Newhall navel orange during postharvest storage

Abstract

Gannan Newhall navel orange was treated by ethylene and ethephon separately. The color of Gannan Newhall navel orange peel was influenced significantly by ethylene and ethephon treatments. During postharvest storage, the ratio of chlorophylls and carotenoids in the peel reduced which led the peel color changing from green to yellow when treated by ethephon and to orange‐red when treated by ethylene. Results of the CIELAB chroma system evaluation were consistent with sensory evaluation. Ethylene and ethephon treatments decreased β‐carotene and lutein contents and increased β‐cryptoxanthin content largely (converted β‐carotene to β‐cryptoxanthin) in citrus peel. Besides, ethylene and ethephon treatments could convert yellow violaxanthin to neoxanthin or zeaxanthin. In ethylene treatment, its peel color changing to orange‐red due to β‐cryptoxanthin converted to β‐citraurin, which made Gannan Newhall navel orange exhibited the welcomed color (orange‐red). It was desirable for citrus postharvest process. Practical applications The color of citrus fruit has become an important factor affecting fresh fruit price and market competitiveness. Studies have shown that citrus peel color is mainly affected by the content and proportion of chlorophylls and carotenoids. This study is aimed to illustrate the transformation of carotenoids and the mechanism of regulation of ethylene on the navel orange peel changing from green to orange‐red. The results of this research could provide scientific supports for citrus's atmosphere controlled storage, which could produce added value.

Impact of ethylene degreening treatment on sensory properties and consumer response to citrus fruits

“…With the 'Navelina' oranges, degreening treatment enhanced the colour from pale orange tones at harvest to intense orange tones (Figure 2 and 3). Orange colour development of the citrus peel as result of the degreening treatment has been associated with the accumulation of carotenoid pigments, such as zeaxanthin and mainly β-cryptoxanthin and β-citraurin (Hu et al, 2018;Sumiashi et al, 2018). It is noteworthy that temperature itself had an effect on the rind colour of the studied three mandarins as the control fruit showed enhanced colour compared to the fruit at harvest (Figure 3).…”

“…In fact, in European Union markets, the proportion of the fruit surface with a minimum colouration is one of the maturity indexes used to define fruit quality (Lado et al, 2018). Thus a common practice to enhance the skin colour development of early citrus cultivars is to apply the ethylene degreening treatment (Machado et al, 2015;Da Costa et al, 2017;Hu et al, 2018). Citrus fruit are classified as non-climateric according to their respiration and ethylene production patterns (Kader, 2002).…”

The Effect of Ethylene on the Color Change and Resistance to Botrytis cinerea Infection in ‘Kyoho’ Grape Fruits

“…Which is evident from the various past research findings in climacteric fruits [44]. Although relatively few studies have been carried out on non-climatic fruits, recent studies have shown that ethylene also has an important role to play in the coloring and maturation of grape berries [45,46]. However, the application of ethephon observed dual effect on grape fruit ripening.…”

Effects of Degreening Treatment on Quality and Shelf-Life of Organic Lemons

“…Thus, the degreening treatment developed Agronomy 2022, 12, 270 2 of 12 in controlled chambers is considered as one of the postharvest strategies used to promote the optimal harvest time of lemon fruits independently of environmental conditions. In organic production, temperature, relative humidity, and carbon dioxide concentrations are controlled during the postharvest storage of lemon fruits until they change their skin colour from green to favourable yellow, since nowadays the exogenous application of ethylene is banned [7].…”