Assessment of quality parameters in grapes during ripening using a miniature fiber-optic near-infrared spectrometer.
Changes in the chemical properties of wine grapes during ripening were studied using near-infrared (NIR) spectroscopy. A miniature fiber-optic NIR spectrometer system working in transmission mode in the spectral region (700 - 1,060 nm) was evaluated for this purpose. Spectra and analytical data were used to develop partial least square calibration models to quantify changes in the major parameters used to chart ripening in this fruit. NIR spectroscopy provided excellent precision for soluble solid content and for reducing sugars, and good precision for maturity index, while for pH and titratable acidity the miniature NIR spectroscopy instrument proved less accurate. The performance of the instrument in classifying wine grapes by grape type and by irrigation regime was also studied. Percentages of correctly classified samples ranged from 82.7% to 96.2%. The results show that the monitoring of soluble solid content and reducing sugars' changes in wine grape quality parameters during ripening, as well as the classification of grapes, can be performed non-destructively using a miniature fiber-optic NIR spectrometer.
Fernández-Novales
Juan
J
Centro de Investigación y Formación Agraria de Cabra-Priego, Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Consejería de Agricultura y Pesca, Junta de Andalucía, Cabra, Córdoba, Spain.
López
María-Isabel
MI
Sánchez
María-Teresa
MT
García-Mesa
José-Antonio
JA
González-Caballero
Virginia
V
D000383:Agriculture / Q000379:methods; D002138:Calibration; D002264:Carboxylic Acids / Q000032:analysis; D018556:Crops, Agricultural / Q000737:chemistry*; D004040:Dietary Carbohydrates / Q000032:analysis; D016002:Discriminant Analysis; D005240:Feasibility Studies; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005524:Food Technology; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development*; D006863:Hydrogen-Ion Concentration; D008904:Miniaturization; D015233:Models, Statistical; D018521:Plant Physiological Phenomena; D011786:Quality Control; D015203:Reproducibility of Results; D013045:Species Specificity; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation*; D027843:Vitis / Q000737:chemistry* / Q000145:classification; D014920:Wine
D002264:Carboxylic Acids; D004040:Dietary Carbohydrates