Exploring oxygen diffusion and respiration in pome fruit using non-destructive gas in scattering media absorption spectroscopy
Manju Joseph, Robbe Van Beers, Annelies Postelmans, Bart Nicolai and Wouter Saeys
Postharvest Biology and Technology, Volume 173, March 2021, 111405
2021
บทคัดย่อ
Abstract
Pome fruit stored under a controlled atmosphere (CA) often suffers hypoxia due to the mismatch of O2 level in the storage rooms and the fruit’s O2 consumption. Fruit response-based O2 sensing and control could be an efficient approach to reduce the hypoxia-related physiological disorders and therefore increase the shelf life of stored fruit. This research aims to validate and evaluate the application of nondestructive gas in scattering media absorption spectroscopy (GASMAS) O2 sensing in fruit post-harvest. In the first stage, the GASMAS O2 sensor was validated on a fruit mimicking multilayer model system where a high correlation was observed between the measured and reference O2 partial pressures (r2 ≥ 0.9). Later, the GASMAS sensor was evaluated on two apple cultivars (Malus x domestica ‘Golden delicious’, Malus x domestica ‘Nicoter’) and one pear cultivar (Pyrus communis ‘Conference’). The observed GASMAS signal from the ‘Golden delicious’ apples were nearly 2 times higher than the signal from ‘Nicoter’ apples and 5 times higher than from the ‘Conference’ pears. In the next stage, GASMAS measurements were taken on water submerged ‘Golden delicious’ apple and ‘Conference’ pear to investigate the difference in O2 consumption in those fruit. The calculated relative O2 changes during respiration and evolution of the O2 partial pressure after nitrogen treatment for both the fruit were found different. It was hypothesized that these findings may be attributed to variations in fruit porosity. And finally, the influence of skin and additional surface coating on the gas exchange was studied by immersing unpeeled, peeled and coated samples in the gaseous nitrogen for 2 h before measurement. The coating was found to reduce the gas exchange compared to the unpeeled samples which already exhibited a lower exchange rate than the peeled samples.