The pick of the crop

Top quality class fruit can demand a price double that of Class II. As the criteria for classification includes internal quality as well as external appearance, the fresh fruit and vegetable (FFV) sector would benefit greatly from inclusion of high-tech sorting methods on the production line.

The FRUITGRADING (A low cost sorting solution for the fruit sector based on the evaluation of internal fruit quality) project has just completed work on new fruit sorting technology. Goals were in line with the major objectives of the European Common Agricultural Policy: to improve European fruit quality and to promote the consumption of healthy food.

Research focused on apple, pear, peach, and kiwi and used two technologies - magnetic induction spectroscopy (MIS) and diffuse reflectance spectroscopy for evaluating electrical and optical characteristics, respectively. The data from these tests was then analysed and correlated with commercially important fruit features.

Sugar and acidity were predictable from the optical data and firmness in apples correlated well. Electromagnetic spectrum results can be linked to post-harvest changes in firmness as well as ripeness from the radio frequency band in the range. However, further refinements are necessary to reduce sensor noise and minimise errors.

The two sensors have been integrated into a fruit sorting line, calibrated for even better fruit property correlations and validated. The MIS sensor has been made more rugged for the rigours of on-line use.

FRUITGRADING has organised training and dissemination to optimise use of the new technologies in the FFV sector. Activities include magazines, newsletters, participation in conferences and workshops.

For producers, new sorting methods permit production on the basis of 'premium quality' using suitable quality benchmarks for critical parameters. As the technology is non-invasive, percentage of discarded fruit will be reduced. Moreover, fruit farmers can implement pre-sorting strategies before fruit storage in maturation chambers.

There has been a steady rise in the demand for premium fruit - an average of 8.9 % increase per year in the last 5 years in the United States - despite a drop in overall consumption. FRUITGRADING technology will enable the producer to respond to these market changes and increase profitability.