The DA-Meter - developed by Prof. Costa's team from the University of Bologna - is an instrument that, by means of its absorbency properties, allows tomeasure the chlorophyll's content in a fruit. The content in chlorophyll in a fruit is a precise index of a fruit's ripening state.

Thus, the DA-Meter allows to know the ripeness state, and the way it works does not depend on the season’s weather conditions, a factor which influences other kinds of measurement In fruit and vegetables, establishing the optimal harvest time is a crucial issue, since fruit shelf-life potential and quality are closely related to the ripening stage at the harvest. In cold store it is very importants to establish maturity changes as well.
The DA index, measured with the DA-Meter, is useful at many stages in the production and consumption's cycle of fruit. As a matter of fact, it can be used:
1) by the farmer, in order to optimize the trees pruning, to obtain a very homogeneous product and, as a result, to reduce the number of picking stages;
2) by the farmer, during the harvest-time, in order to identify the best moment for the picking;
3) in the cold rooms, in order to know the maturation state of the stored fruit;
4) in the packing-house, the DA-Meter has been used to select the correct fruit for different marketing destinations (less ripe fruit for distant markets, riper fruit for local market).
5) at the retailer, in order to buy products at the intended maturation level and in order to select the most ripened product for selling.
The DA-Meter is a very promising tool both for practical and scientific applications, since it allows to monitor on-tree fruit ripening (as well on the same fruit):as a matter of fact, decreasing index ranges correspond to increasingly advanced stages of the ripening process, as showed by the differences in ethylene emissions, and by the quality traits of fruit with different DA values.