Respiratory quotient: innovative method for monitoring ‘Royal Gala’ apple storage in a dynamic controlled atmosphere

Anderson Weber,Elizandra Pivotto Pavanello,Auri Brackmann,Rogério De Oliveira Anese,Vanderlei Both,Fabio Rodrigo Thewes

doi:10.1590/0103-9016-2013-0429

Anderson Weber, Elizandra Pivotto Pavanello + Show 4 more

Open Access

https://doi.org/10.1590/0103-9016-2013-0429

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Journal: Scientia Agricola	Publication Date: Feb 1, 2015
Citations: 67	License type: cc-by

Affiliation: Universidade Federal de Santa Maria

Abstract

Apples (Malus domestica, Borkh.) which are not stored at low temperature or in a properly controlled atmosphere (CA) may have a high metabolic rate during the postharvest stage resulting in losses in quality. The aim of this study was to evaluate the quality of ‘Royal Gala’ apple fruit stored in accordance with a new method of dynamic controlled atmosphere (DCA).The respiratory quotient (RQ) was monitored at two temperatures which were then compared using a commercially available technology based on chlorophyll fluorescence DCA (DCA-CF) and static CA. Ethylene production and respiration rates were lower in apples stored in DCA than in CA, as a result of lower 1-aminocyclopropane-1-carboxylate oxidase activity, especially in apples stored in DCA-RQ2. Flesh firmness of apples stored in DCA did not differ from those stored in CA. Apples stored at 1 °C had less flesh breakdown occurrence and a high percentage of healthy fruit. ‘Royal Gala’ stored at DCA-RQ2 had less flesh breakdown than apples stored in CA; however, the apples stored in DCA-CF did not differ from those stored in DCA-RQ2 and CA. Apples stored at the highest RQ value (6 and 4), especially at 0.5 °C, had low O2 injury occurrence after storage. However the increase in temperature to 1.0 °C, reduced the occurrence of this disorder. Therefore, storage in DCA-RQ2 at 1 °C or DCA-CF at 0.5 °C are the recommendations of preference for ensuring maintenance of quality in ‘Royal Gala’ apples after eight months of storage.

Highlights

In Brazil, ‘Royal Gala’ apples (Malus domestica, Borkh.) are stored after harvest under controlled atmosphere (CA) conditions with about 1.0 to 1.2 kPa O2 and 2.0 to 2.5 kPa CO2 at a low temperature (0.5 to 1 °C), and relative humidity of about 94 %, for up to seven months (Weber et al, 2011; 2012)
The aim of this study was to evaluate the quality of ‘Royal Gala’ apple fruit stored in accordance with a new method of dynamic controlled atmosphere (DCA).The respiratory quotient (RQ) was monitored at two temperatures which were compared using a commercially available technology based on chlorophyll fluorescence DCA (DCA-CF) and static CA
‘Royal Gala’ stored at DCA-RQ2 had less flesh breakdown than apples stored in CA; the apples stored in DCA-CF did not differ from those stored in DCA-RQ2 and CA

Summary

Introduction

In Brazil, ‘Royal Gala’ apples (Malus domestica, Borkh.) are stored after harvest under CA conditions with about 1.0 to 1.2 kPa O2 and 2.0 to 2.5 kPa CO2 at a low temperature (0.5 to 1 °C), and relative humidity of about 94 %, for up to seven months (Weber et al, 2011; 2012). If oxygen levels are excessively reduced, hypoxic and even anoxic zones may develop and switch from aerobic respiration to fermentation, which can lead to physiological disorders (Pesis, 2005; Gasser et al, 2010). A new trend in commercial CA is to consider the use of a dynamic rather than a static controlled atmosphere. In the dynamic controlled atmosphere (DCA), the oxygen level can be changed during the storage period, but remains always slightly above the lowest oxygen limit (LOL). Since 2010, we have been testing a new method to store apples in DCA based on the respiratory quotient (RQ). Monitoring the RQ will identify the moment when apples reach a critical level of ethanol production, which might damage their tissue (Gasser et al, 2010)

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