A prototype of a stationary DA device to group apricot fruits in classes of homogeneous ripening

In apricot ( Prunus armeniaca L.), fruit quality at consumption and shelf-life potential are strictly related to the ripening stage reached at harvest. As a result, definition of the optimal harvest time is a crucial issue and, nowadays, this is performed on the basis of fruit size, skin color and some internal quality traits, such as flesh firmness ( FF), soluble solids content ( SSC) and titratable acidity ( TA), that are determined by standard techniques that require destruction of the fruit sample. Recently, extensive research has focused on the development of non-destructive visible/ near-infrared spectroscopy ( vis/NIRs) techniques that allow the ripening stage to be expressed as a new maturity index, called the index of "absorbance difference" ( IAD). The IAD is used to establish, under field conditions, the optimal harvest time related to the ripening stage at harvest with a portable DA meter. More recently, a stationary DA machine prototype has been realized, allowing the grouping of fruits in classes of homogeneous ripening at the packing-house level. Preliminary results obtained with this prototype on some apricot cultivars grown in Valais ( Sion, Switzerland) are reported. The results obtained showed that the IAD values obtained with the stationary DA allow fruit to be grouped according to their ripening stage. The data were comparable with those obtained with a portable DA meter, and correlate with standard internal quality traits.