Biomechanics of fruits and vegetables

The scope of fruit and vegetable biomechanics is reviewed. Sources of mechanical injury to produce in harvesting, processing, storage, packaging and transportation are briefly described. A survey of produce handling and transportation environments was conducted, whereby an envelope model encompassing composite spectra of trucks, railroad, marine and cargo aircraft is presented. The protective quality, i.e. strength of shipping containers is quantified in static and dynamic loading such as encountered in storage, handling and transportation. Mechanical response of fruits and vegetables in quasistatic and dynamic loading are formulated by a nonlinear rheological model, whereby a time and deformation dependent relaxation modulus is defined. A realistic link is established between the model and real fruits and vegetables by test procedures for determination of the parameters in the governing nonlinear equations. Based on the nonlinear relaxation modulus, mechanical damage of fruits and vegetables is quantified for static compression, transients and vibration loading as well as for combined static and dynamic loading, by equations of contact circle diameter, bruise depth and contact pressure. Distribution of loads over a maximal number of contact points per fruit is linked to geometrical patterns of produce packs. The application of Shock Damage Boundary techniques for produce-package testing is described along with a case study comparing the protective qualities of two types of apple packs. Produce damage quantification by direct fruit inspection in terms of a 'Bruise Index' is described, including a practical example, comparing the protective qualities of three types of apple packs in shipping tests. Indirect methods of mechanical injury evaluation, based on weight loss and CO2 emission differences between bruised and wholesome fruits are also briefly discussed.     

Dynein branches out

Individual neurons form specific elaborate dendritic structures that receive presynaptic information. The pattern of dendritic branching is regulated by the microtubule-associated motor protein dynein, which is responsible for the transport of essential endosomes and other organelles into the dendrites.     

Ubiquitin branches out

In recent years, there has been a marked expansion of recognized roles for ubiquitin (Ub) in processes other than proteasome-dependent proteolysis, as well as a proliferation of Ub-like proteins that also function through covalent attachment to other proteins. The full diversity of functions for these proteins was on display at the American Society for Cell Biology (ASCB) meeting on "Non-Traditional Functions of Ubiquitin and Ubiquitin-Like Proteins" held at Colorado College in Colorado Springs, Colorado (August 11-14th, 2002).     

Gamma radiation effects on fruits and vegetables

Several million dollars are lost in the United States each year as a result of post harvest diseases of crops. Claim costs to railroads alone in 1958 amounted to $11 million. This work demonstrates that it is possible to extend the shelf-life of fresh fruits and vegetables at room as well as at refrigeration temperatures by gamma radiation, by surface pasteurization, sprout inhibition, and also by retarding the ripening processes. The information presented should be useful to researchers, shippers, packers, and processors.     

Market diseases of fresh fruits and vegetables

Bruising, crushing, and other mechanical injuries cause very serious losses during the handling, transportation, storage, and marketing of fresh fruits and vegetables. Spoilage caused by molds and bacteria exacts a heavy toll. Freezing, chilling injury, and various physiological disorders add to the consumer cost of living. Careful handling, proper refrigeration, good marketing practices, and the use of safe, approved chemical treatments can reduce marketing losses.     

Biosurfactant-producing yeasts widely inhabit various vegetables and fruits

The isolation of biosurfactant-producing yeasts from food materials was accomplished. By a combination of a new drop collapse method and thin-layer chromatography, 48 strains were selected as glycolipid biosurfactant producers from 347 strains, which were randomly isolated from various vegetables and fruits. Of the producers, 69% were obtained from vegetables of the Brassica family. Of the 48 producers, 15 strains gave relatively high yields of mannosylerythritol lipids (MELs), and were identified as Pseudozyma yeasts. These strains produced MELs from olive oil at yields ranging from 8.5 to 24.3?g/L. The best yield coefficient reached 0.49?g/g as to the carbon sources added. Accordingly, MEL producers were isolated at high efficiency from various vegetables and fruits, indicating that biosurfactant producers are widely present in foods. The present results should facilitate their application in the food and related industries.     

Storage characteristics of some vegetables and soft fruits

Rates of carbon dioxide production, in air and in 3 % 0₂, over a range of temperatures, were measured for over thirty commodities, and rates of evaporation, under known water vapour pressure deficit, measured for most of them. Optimum storage conditions in air for each commodity were determined. Storage life under these optimum conditions, and under the nearest practical approximation to them, was estimated. In most cases the optimum temperature is o^oC, examples of exceptions being runner beans, cucumbers, potatoes, green peppers and tomatoes. The humidity should usually be high, 100 % r.h. often being optimal, particularly for leafy vegetables, provided the temperature is low. Commodities resistant to evaporation, however, such as the onion, may with advantage be stored at lower humidities, thus reducing the microbial hazards.     

Study of allergens from vegetables, fruits and berries

Different methods of obtaining allergens from vegetables, fruit and berries have been evaluated. Two technologies for obtaining food allergens have been considered; of these, Coca's method has proved to be more technological, economical and less labor-consuming. The newly developed technology has made it possible to obtain stable, safe and specifically active allergens which may be used for diagnosing food allergy.     

Human genetics branches out in Barcelona

A report of the European Human Genetics Conference, Barcelona, Spain, 31 May-3 June 2008.     

Fungi, quality and safety issues in fresh fruits and vegetables

The role of moulds in the spoilage of fresh fruits and vegetables is discussed. Although the major problems are economic with a significant loss of useful food materials, there are a few examples implicating a role for mycotoxins in the safety of fresh fruits. The significance of the mycotoxins patulin, ochratoxin and tenuazonic acid will be reviewed.     

Recombination: homologous recombination branches out.

Homologous recombination can be divided into three key steps: strand exchange, branch migration and resolution. The identification of a protein complex that catalyses branch migration and Holliday junction resolution argues that the mechanism of homologous recombination is conserved from bacteria to man.