Fruit ripening is a coordinated process involving changes in colour, texture, flavour, aroma and other attributes of fruit quality. Recognition of the central role of ethylene as the natural ripening agent in climacteric fruits has led to the current systems of handling, storage and transport of fruits that have evolved over the years. All these systems directly or indirectly subdue the synthesis or action of ethylene.
The principle underlying the use of controlled or modified atmospheres is to reduce respiration and ethylene synthesis and action, by increasing carbon dioxide and decreasing oxygen levels. The introduction of barrier plastics has permitted the modification of the atmosphere in the field container, shipping bushel and retail package. The main aim of this programme concerns the improvement of fruit storage including the control of ethylene action at the genetic, metabolic, and technological level.
The project has involved investigation of methods of improving the storage capability of fresh fruits, principally by control of ethylene. Techniques which have already shown promise include the use of carbon dioxide shocks, new means for removing ethylene in storage rooms, adapting the physical properties of plastic films by microperforation and the use of food compatible coatings to reduce the incidence of scald during the storage of apples.
The principal aim of the project is to improve the shelf life of stored fruits by controlling ethylene synthesis and action. For that purpose several means have been investigated. Industrial stimulation of the new techniques being devised have not yet been performed. Due to the advancement of the work some large scale experiments have been made (gas antagonists, microperforation of films, etc). Using practical parameters for determining quality, and assessment of the heterogeneity of melons the changes in the environmental conditions at various stages of the commercial circuit have been followed. They show great fluctuations especially at the level of the distribution platform and transport.
Based on the knowledge already established of the major role of this hormone in the ripening and senescence of climacteric fruits, the innovative aspects of this programme can be divided on 3 parts:
The control, through genetics and genetic engineering, of the expression of genes involved directly in ethylene synthesis, or closely correlated with the action of ethylene. The goal is to create new plants with fruits of better storage capabilities. The suitability of the new varieties to technological treatments and their resistance to chilling and low oxygen injury will be determined in close cooperation with participants working on storage processes.
The control of ethylene action during fruit storage by external factors, in particular the gaseous environment. The action of carbon dioxide shocks, low oxygen levels and of new gases or chemicals antagonizing ethylene action will be studied.
The control of ethylene effects through technological processes. This part of the study is based on the control of shelf life of the fruits by acting on the composition of the internal atmosphere through modified (MA) or controlled (CA) atmospheres. The general approach consists of an integrated study of the fruit in its environment (temperature, gases). It includes the application of new techniques of storage, packaging and coating for the maintenance of fruit physiology and quality. This research will be extended by studies of the industrial feasibility of the new proposed procedures.
The study will be applied not only to the model fruits (tomatoes and melons), but also to other fruit species of economic importance.
Funding SchemeCSC - Cost-sharing contracts
RG6 6AH Reading / Silchester