The stage of fruit ripeness at the harvest is a fundamentally important part of determining the final quality of the product and its conservation potential.
The quality of each fruit is determined by a set of attributes or characteristics.
The challenge is to identify one only parameter that will determine fruit quality at the harvest and will guarantee the best quality.
In the ‘80s, the industrial research world took its first steps toward the study and development of non-destructive technologies to determine the quality of fruit. They tried to achieve, using non-destructive tests, the same results usually attained by destructive tests, such as the hardness, the Brix degree, acidity and so on.
With the appropriate correlations, these parameters can effectively be obtained using visible and near infrared spectroscopic analysis. The measures achieved are subjected to the same problems as the ones achieved with canonical methods, and they are also subjected to seasonal problems. The same correlation between the spectrum and the parameters depends on many factors, therefore it is necessary to destroy and analyze a big amount of fruit in order to obtain the calibration model.
At the end of the ‘90s, the Department of Tree Cultivation (Coltura Arborea) at the University of Bologna started studying the near infrared spectroscopy as a possible non-destructive solution to determine the quality of fruit.
With the patent application M02005A000211 registered at “Alma Mater Studiorum-University of Bologna“, an invention by Costa Guglielmo, Noferini Massimo and Fiori Giovanni was protected. This invention refers to an index called DA, which is specifically connected to the stage of maturity of fruit and to the methods and instruments used to measure the above mentioned DA.
The DA Index® was created to evolve and simplify the systems mentioned above, in order to avoid the problems associated with them. It works by measuring a value that is not actually correlated to the seasonality (the presence of chlorophyll) and that consequently does not require calibrations. Furthermore, measuring the absorbance of only two wavelengths allows one to perform the measurement using simple, low cost devices.
Based on the encouraging results obtained using this technology and the optical characteristics of the fruits, the DA-Meter ™ , or what we now know as the DA-meter®, was born.
Several years of tests have allowed to develop this portable instrument and non-destructive that allows to analyze a large number of samples on different types of fruits and be used in the field, in a fast and economical.