Articles
A modelling approach to explain low apparent RQ-measurements of (D)CA stored Conference pear fruit
Article number
1311_31
Pages
249 – 256
Language
English
Abstract
Recently, interest goes to the respiratory quotient (RQ), the ratio of the CO2 production rate and the O2 consumption rate of the fruit, as a bioresponse to detect low O2 stress to be used in dynamic controlled atmosphere storage (DCA). RQ shows a steep increase upon low O2 stress when fermentation becomes the dominant mode to metabolise sugars for providing energy.
This makes RQ a good indicator for low O2 stress, which can be calculated by measuring the gas composition changes in the storage room.
The technology has been shown to result in better post-storage quality for various apple cultivars.
However, sometimes, low RQ values are observed during RQ-based DCA storage which remain poorly understood until now.
In this work, the relation between non-steady-state gas conditions of the fruit-Hstorage environment system and RQ-values measured in the headspace of the storage environment is investigated.
Dedicated jar experiments were conducted to evaluate the effect of non-equilibrium gas conditions on measured rates of O2-consumption and CO2-production by fruit respiration.
A gas transport model was developed.
The experimental scenarios were simulated and results were compared to the experimentally obtained measurements.
The results indicate that non-steady-state between fruit-environment gas conditions has a significant effect on measured CO2 production rates, while little effect on measured O2 consumption rates was observed.
An apparent measured RQ of 0.65 was related to an actual RQ-value of 1.0 inside the fruit cells by the model.
This makes RQ a good indicator for low O2 stress, which can be calculated by measuring the gas composition changes in the storage room.
The technology has been shown to result in better post-storage quality for various apple cultivars.
However, sometimes, low RQ values are observed during RQ-based DCA storage which remain poorly understood until now.
In this work, the relation between non-steady-state gas conditions of the fruit-Hstorage environment system and RQ-values measured in the headspace of the storage environment is investigated.
Dedicated jar experiments were conducted to evaluate the effect of non-equilibrium gas conditions on measured rates of O2-consumption and CO2-production by fruit respiration.
A gas transport model was developed.
The experimental scenarios were simulated and results were compared to the experimentally obtained measurements.
The results indicate that non-steady-state between fruit-environment gas conditions has a significant effect on measured CO2 production rates, while little effect on measured O2 consumption rates was observed.
An apparent measured RQ of 0.65 was related to an actual RQ-value of 1.0 inside the fruit cells by the model.
Authors
N. Bessemans, B.E. Verlinden, M. Janssens, P. Verboven, M.L.A.T.M. Hertog, B.M. Nicolaï
Keywords
dynamic controlled atmosphere, non-equilibrium, respiratory quotient, gas exchange, Pyrus communis L
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