Hydroxyl Radical Oxidation Processes in Vegetables: Review and Safety Criteria
Abstract
Ethylene is an invisible, colorless and odorless gas, which has no known dangerous effect in humans, on concentrations found within the storage chain and sale of fruits and vegetables. The ethylene molecule is relatively small and simple: it consists of two carbon atoms associated with four hydrogen atoms. The molecular weight of ethylene is 28.05 gmol-1 and fruits and vegetables produce different amounts of ethylene as they mature. Usually, ethylene cannot be detected by humans, although sometimes only people with well-developed olfactory ability can smell large amounts, but to this fact other volatile organic compounds of fruits and vegetables also contribute. Since its specific weight (1,178 kgm-3 to 15oC) is similar to that of air (1,225 kgm-3 to 15oC), ethylene freely diffuses to any other adjacent fruit or vegetables and to the spaces in which they are stored.
In addition to CO and O , ethylene is the most important gas to be monitored and controlled in the fruit and vegetable supply 2 2 chain. Less than one part per million (1 ppm) in volume of ethylene gas, is enough to trigger the maturation process of the climatic fruit (which can continue to mature, once collected). Ethylene is considered a plant hormone that controls a wide range of physiological processes. During storage, after harvesting fruits and vegetables, ethylene may induce effects including senescence, over-maturation, accelerated quality loss, increased susceptibility to fruit pathogens and affecting different physiological processes. In addition to the endogenous production of ethylene by plant tissues, there are also external sources such as contaminants and the own metabolism of plants and fungi.
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Introduction
It is known that ethylene concentration in of ethylene in fruit and vegetable storage areas and the presence of harmful elements for products stored in cold rooms is a problem for production and consumer companies as fruits and vegetables produce different amounts of ethylene as they ripen (1). Among the harmful elements are volatile organic compounds (VOCs) (2), as a result of the metabolism of stored products the same, fungi, dispersed by the air through their spores and ethylene which, although encompassed in VOCs, deserves attention apart, given its character as a vegetable hormone, triggering the ripening processes in fruits.
Conclusion
Based on the results of this review, we could suggest that the preservation of fruits and vegetables in cold rooms is dependent on the accumulation of VOC, the proliferation of microorganisms, the conditions of the chambers and the characteristics of each vegetable. The elimination of VOCs (including ethylene) can be used as an indicator of the operation of oxidizing processes as environmental scrubbers of the storage and storage chambers.
The previously determined results of this review, it allows to affirm that the radical OH• is the oxidizing element responsible for the AOP used and, consequently, presents a potential action on the modulation of ethylene levels that favourably affect fruits and vegetables, as well as its microbiological control.
