Accumulation of anthocyanins (Anth) in whole winegrape (Vitis vinifera L.) bunches still attached to vine plants was followed non-destructively using a fluorescence-based sensor. The method is based on the screening of fruit chlorophyll fluorescence and allows the Anth contents of intact berry skin to be measured. With increasing Anth content, less excitation light is transmitted to the deeper chlorophyll layers, and thus the chlorophyll fluorescence signal decreases proportionally. Tests were carried out in 2009-2010 in vineyards of Central Italy. Measurements were performed weekly from véraison to harvest on Sangiovese, Cabernet Sauvignon, Merlot, Shiraz and Petit Verdot cultivars. The ANTHRG index showed a different time evolution and Anth accumulation for the cultivars. The data obtained from the sensor were compared with the spectrophotometric analyses in order to assess the anthocyanoside content. The fluorescence-based sensor used in the present study represents a rapid and non-invasive tool for assessing grape phenolic maturity and quality, and may represent in perspective an alternative to destructive laboratory analyses, which are time-consuming and require an accurate sampling approach.
A non-invasive optical method for quality control of maturing wine grapes
MIELE, SERGIO
2011-01-01
Abstract
Accumulation of anthocyanins (Anth) in whole winegrape (Vitis vinifera L.) bunches still attached to vine plants was followed non-destructively using a fluorescence-based sensor. The method is based on the screening of fruit chlorophyll fluorescence and allows the Anth contents of intact berry skin to be measured. With increasing Anth content, less excitation light is transmitted to the deeper chlorophyll layers, and thus the chlorophyll fluorescence signal decreases proportionally. Tests were carried out in 2009-2010 in vineyards of Central Italy. Measurements were performed weekly from véraison to harvest on Sangiovese, Cabernet Sauvignon, Merlot, Shiraz and Petit Verdot cultivars. The ANTHRG index showed a different time evolution and Anth accumulation for the cultivars. The data obtained from the sensor were compared with the spectrophotometric analyses in order to assess the anthocyanoside content. The fluorescence-based sensor used in the present study represents a rapid and non-invasive tool for assessing grape phenolic maturity and quality, and may represent in perspective an alternative to destructive laboratory analyses, which are time-consuming and require an accurate sampling approach.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
