Extremely low-oxygen storage: aerobic, anaerobic metabolism and overall quality of apples at two temperatures

Vagner Ludwig,Erani Eliseu Schultz,Fabio Rodrigo Thewes,Lucas Mallmann Wendt,Suele Fernanda Prediger Schmidt,Auri Brackmann,Magno Roberto Pasquetti Berghetti

doi:10.1590/1678-4499.20190496

Abstract

ABSTRACT The objective of this work was to evaluate the effect of extremely low-oxygen storage on the aerobic, anaerobic metabolism and overall quality maintenance of ‘Royal Gala’ and ‘Galaxy’ apples stored at two temperatures. For ‘Royal Gala’ apples, four treatments were evaluated in a two-factor scheme (2 × 2), with two storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; and two temperatures (1.0 and 1.5 °C). For ‘Galaxy’ apples, the experiment was conducted in a two-factor (3 × 2) scheme with three storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; [3] 0.4 kPa O2 + 1.2 kPa CO2, and two temperatures (1.0 and 1.5 °C). The ‘Royal Gala’ apples stored under 0.8 kPa O2 + 1.6 kPa CO2 at 1.5 °C had higher flesh firmness, healthy fruit and soluble solids along with lower incidence of flesh breakdown and mealiness. The ‘Galaxy’ apples stored under 0.4 kPa O2 + 1.2 kPa CO2, at temperature of 1.5 °C had lower 1-carboxylic acid-1-aminocyclopropane (ACC) oxidase enzyme activity, ethylene production, occurrence of mealiness, when compared to 1.0 °C. The storage of these two cultivars at 1.5 °C with extremely low O2 partial pressures is possible. The possibility to increase the storage temperature from 1 °C, which is traditionally used for these mutants, to 1.5 °C allows to keep better quality with the advantage of energy saving.

Highlights

Most apples produced in Brazil belong to the ‘Gala’ cultivar and its spontaneous mutants, including ‘Galaxy’ and ‘Royal Gala’, totalizing a production of 326,658 t in 2017/2018 crop, representing 66% of the national apple production (Agapomi 2018)
Fruit stored under 0.4 kPa O2 + 1.2 kPa CO2 and 0.8 kPa O2 + 1.6 kPa CO2 had a correlation to flesh firmness, healthy fruit, titratable acidity, acetaldehyde concentration, decay, pulp cracking and flesh breakdown, fact that did not lead to these treatments having a lower healthy fruit percentage (Fig. 2)
Fruit stored under 0.4 kPa O2 + 1.2 kPa CO2, after seven days of shelf life, had a lower ethylene production than the fruit kept under 0.8 kPa O2 + 1.6 kPa CO2, this may be explained by the lower activity of the ACC oxidase enzyme of fruit stored under 0.4 kPa O2 + 1.2 kPa CO2 at 1.5 °C (Fig. 3a), similar results were found by Both et al (2014b), Thewes et al (2015), and Weber et al (2013)

Summary

Introduction

Most apples produced in Brazil belong to the ‘Gala’ cultivar and its spontaneous mutants, including ‘Galaxy’ and ‘Royal Gala’, totalizing a production of 326,658 t in 2017/2018 crop, representing 66% of the national apple production (Agapomi 2018). The application of 1-methylcyclopropene (1-MCP) to apples stored under controlled atmosphere (CA) allowed an increase of the storage temperature to 2.5 °C, obtaining an electrical energy saving of 26 and 35% for the ‘Jonagold’ and ‘Gala’ apples, respectively (Kittemann et al 2015). The use of dynamic controlled atmosphere by chlorophyll fluorescence (DCA-CF) allowed 20% of energy savings in apples stored for seven months (Kittemann et al 2015) In both studies, the increase in temperature did not result in Extremely low-oxygen storage fruit quality losses; quality maintenance varied among cultivars and some were more sensitive to the increase in temperature. It is important to conduct studies to verify the feasibility to increase the storage temperature and its interaction with extremely low O2 partial pressures in maintaining fruit quality

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