Future trends

It is clear that the conventional thermal methods can lead to desirable destruction of microbial pathogens and spoilage organisms and endogenous, desirable changes such as protein coagulation, starch swelling, textural softening and formation of aroma components. However, undesirable changes also occur, such as loss of vitamins and minerals, formation of thermal reaction components of biopolymers, and in minimal processing terms, loss of fresh appearance, flavor and texture. The classical...

References

1 abeues f b, morgan p w and sautveit jr m e, Ethylene in Plant Biology, London, Academic Press, 1992. 2 yang s f and hoffman n e, 'Ethylene biosynthesis and its regulation in higher plants', Annu Rev Plant Physiol, 1984 35 155-89. 3 de vries h s m, wasono m a j, harren f j m, woutering e j, van der vauk h c p m and reuss j, 'Ethylene and CO2 emission rates and pathways in harvested fruits investigated, in situ, by laser photothermal deflection and photoacoustic techniques', Postharvest Biol...

Online detection of plant stress nonvolatile compounds

One of the crucial problems in this field, especially in the case of fruit and vegetable samples, is the detection and identification of non-volatile organic compounds present at low concentration levels, as is the case for most of the phytoalexins produced by the plants. The development of new analytical methods based on both mass spectrometry and laser spectrometry is of major interest75-78 in this field at the time of writing. Although mass spectrometry is widely used in the analysis of...

Antioxidants from fruits and berries overview

Fruits and berries are good sources of antioxidants, including carotenoids, ascorbic acid, tocopherols, flavonoids and phenolic acids. It has been known for a long time that the phenolics, as well as some of the other antioxidant components, are closely associated with the sensory attributes of fresh and processed fruits, berries and other plant foods. Especially, the contribution to colour by carotenoids (yellow to orange and red) and anthocyanins (red to purple and blue) is well known. Also...

Health benefits of whole foods over isolated components

There are many claims made in the media and promotional literature about the qualities and benefits of specific (or groups of) compounds found in fruits and vegetables. We are told that wrinkles, absentmindedness, cancer and clogged arteries (among many other disorders) can be prevented, or alleviated, by consuming these compounds in the form of isolates or concentrated extracts. In such claims the words 'tested', 'effective', 'safe', 'essential' and 'proven' are freely used. In the world of...

The HACCP study

As a preventative approach to ensuring consumer safety, the HACCP concept of food safety management fits with QA philosophy generally and the operation of HACCP systems should fall within the scope of a grower's QA strategy. The resources needed to develop, implement and maintain HACCP systems should be furnished as part of a grower's overall QA provision. Though the employees of a business can directly influence the safety of products through their actions, the business as a whole carries a...

Types of tomato production

The dual use of the tomato has led to two major cultivation systems, one under cover and one in the field. Protected cultivation is specific to production for the fresh market. Its rationale is a gain in productivity. This goal can be achieved through application of transparent cover which reduces the convective and radiative heat losses4 and increases the crop temperature. Productivity can be increased by extending the production period and by reducing the number of limiting factors through...

Increasing consumption what is being done

The strength of the scientific base for the health benefits of diets rich in fruits and vegetables has also guided national policy making in diet and health issues and facilitated community and local programmes that address national dietary goals to increase fruit and vegetable consumption. An example of this is the '5-A-Day for Better Health' programme in the USA that aims to increase consumption of fruits and vegetables to an average of five or more servings a day. The aim is to improve the...

Heat treatment blanching and canning

Heat treatments are responsible for irreversible denaturation of cellular tissue in fruits or vegetables causing softening and juice loss. Vacuum infusion technology was consequently used before heat treatment such as blanching, pasteurising and canning with an aim of limiting thermal damages in the product. It is of particular interest to note the treatment of button mushrooms (McArdle et al., 1974 Gormley and Walshe, 1986 Demeaux et al., 1988), strawberries (Main et al., 1986), apricots...

Grapes

Grapes (vitis vinifera and vitis lubruscana), especially the dark red varieties, contain generous amounts of flavonoids and relatively high levels also of hydrox-ycinnamates that all exert potent anti-oxidant activities in various assay systems. The antioxidant activity of wines have received much attention owing to their possible physiological benefits. However, several of the phenolics present in fresh grapes and grape juice are also potent antioxidants in various in vitro assays, including...

Determining diffusivitiesoffruits

Knowledge of the diffusivities of gases inbulkyplantorgans isessentialinunder-standing physiological changes, gas exchangesandinternalgas composition.The internal gas composition of fruits is and stem (Burg and Burg, 1965 Cameron and Yang, 1982). Burg and Burg (1965) designed a system to determine gas resistancefactorswhichcan beusedtoesti-mate gas diffusivities in bulky plant organsusingtheratioof internalconcentra-tion to the ratio of the production of carbon dioxide and ethylene in the...

Application of plant phytoalexins

As indicated earlier, at the time of writing tens of thousands of secondary plant metabolites have been identified and there is a growing evidence that most of these compounds are involved in the defence mechanisms of plants, representing a large reservoir of natural pesticides to be used for pest control.159 In the particular case of vine plants, one of the most important mechanisms for their resistance to fungal diseases involves the synthesis of trans-resveratrol as a response to the...

Mass and energy balances of tomato crops 541 Carbon

Basically, the production of biomass by a canopy relies on the net assimilation of atmospheric CO2, that is the balance between gross photosynthesis and respiration. It depends on the amount of available energy light and carbon substrate CO2 , and on the ability of the canopy to intercept light and assimilate CO2. In greenhouses, the assimilation of CO2 is not only important for crop growth, it interacts strongly with the composition of the atmosphere. The daily consump tion of carbon by a...

Yield formation

Tomato has been a pioneer species for crop modelling. The formation of yield organ appearance, dry matter production and partitioning has been thoroughly studied and formalised by various approaches, again either mechanistic or empirical. The approach of fruit growth has been based on models of dry matter production. Water fluxes towards the fleshy tomato fruits around 95 water have only recently been studied and modelled. Different approaches of modelling biomass production have been developed...

Areas of application yield prediction and crop management

Management can be defined as the sequence of three operations planning, implementation and control. The planning operation sets up the strategy which encompasses the goals assigned to the cropping system and the means to achieve these goals. Implementation performs the translation from the strategy into actions, while control ensures the proper applications of these actions by constantly monitoring the process and revising the mode of application of the action. The decision process leading to...