A revolutionary device for predicting grape maturity based on NIR spectrometry

Near Infrared spectrometry can be used for measuring the evolution of fruit quality traits. The main characteristics that can be measured are sugar content but also in some case acidity. In conjunction with IFV (institute of Vine and wine), Cemagref research centre and Pellenc SA company have conducted long term researches to get accurate measures of grape sugar and acidity in field conditions, without destroying the fruits. The aim of this collaboration is also to design and build a reliable and low cost portable apparatus. First issues to cope with were the highly variable environmental conditions (temperature, sun light…). Second issues were to find an appropriate design to reduce costs. Until now, more than five prototypes have been developed and tested either in Europe or in Australia, on several varieties and in various conditions. This paper presents the results obtained with this revolutionary device. The calibrations and predictions have been carried out on sugar content (R²= 0,95 and SECV= 1,12 Brix), on acidity (R²= 0, 84 and SECV= 1,35g H2SO4/l) and on water content (R²= 0,8 SECV= 1,89 on red grape). This system will be commercialized soon by PELLENC SA.