Lai and Sighicelli - Gas markers to monitor postharvest quality of horticultural commodities

Antonia Lai* e Maria Sighicelli
UTAPRAD-DIM (Diagnostics and Metrology Laboratory), ENEA Centro Ricerche di Frascati

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Key words: Gas-marker, Acetaldehyde, Ethanol, Ethane, Nitric Oxide, Ethylene.

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Abstract

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One of the most important aims for the food industry is the monitoring and control of variations in fresh horticultural products in post-harvest. The food quality and in particular the food safety have become central in recent years, with particular attention to the risk-free and nutritional beneficial. In fact there is a constant and growing request for a quality food product, that respect both the environment and the foods themselves. The distribution of horticultural products from production zone to marketing, forces the time interval between harvesting and consumption, which could cause, especially if this time is prolonged, loss of taste and aroma, as well as nutrients. So it is necessary to development very sensitive control systems to monitor both biotic and abiotic stress factors as well as in post-harvest and during transport and storage. Although the horticultural products are always selected for their quality and health, during the transport they could be damaged by pathogens or metabolic alterations. The measurement of five of the main biogas (acetaldehyde, ethanol, ethane, ethylene and nitric oxide) emission from fruit and vegetables to different conditions of storage and transport and their detection thresholds is proposed as an important support for monitoring early and non-destructive examination of the health status of fruit and vegetables. These parameters are important in order to develop specific and more sensitive sensors capable to evaluate online health status of the horticultural products and therefore also apply to any emergency and application throughout the food chain. Environmental stresses, such as temperature and/or oxygen concentration, induce alcoholic fermentation instead of respiration. The final products of this different metabolic pathway is Acetaldehyde (AA) and Ethanol (ETOH) instead of CO2 and H2O. Their emission show that the horticultural products are coming in anaerobiosis and there are physiological and metabolic changes leading the development of other off -flavors with losses of characteristic of quality. Both Ethane and Nitric Oxide (NO) are released in answer to oxidative stress. Ethane is detected for cell damage due to lipids peroxidation in animal systems but it has been demonstrated to be also released in plants affected by brown-core. NO induces the hypersensitive disease resistance response and recently, his role in ripening and aging plants has been demonstrated. About ethylene is proposed its monitoring in response of pathogens infestation in non climacteric fruits The minimum levels of these five bio-markers proposed for stress monitoring in harvest horticultural products are shown. More investigations and further biomarker are necessary in order to improve the quality monitoring.

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