Department for Innovation in Biological, Agro-Food and Forest Systems., University of Viterbo, via S. Camillo de Lellis, snc 01100, Viterbo, Italy.
Food Chem. 2012 Dec 1;135(3):1619-25. doi: 10.1016/j.foodchem.2012.05.092. Epub 2012 May 31.
Wine white grape bunches of the Grechetto variety were dehydrated at 10, 20 and 30°C, RH 45% and forced air ventilation of 1.5m/s. Chemical and metabolic changes due to the effect of dehydration were studied at various stages of weight loss: 10%, 20%, 30% and 40%. Berry colour at 10 and 20°C tended to become greener with dehydration but at 30°C, at the final sampling, the colour darkened. Acidity decreased in all samples, while sugars increased. Total phenol content increased at 10°C until 30% weight loss was reached and then declined, while at 20 and 30°C the concentration decreased immediately. The contents of lutein and β-carotene (respectively 68 and 58mg/kg d.w.), representing the 80% of total carotenoids, did not change significantly until the 30% of weight loss, when at 30°C the value increased above all for lutein while at 10 and 20°C, the contents decreased significantly. Daidzein, at 10°C, rose significantly from about 150μg/kg d.w. to 1434μg/kg d.w. at 20% weight loss and then declined; at the same weight loss percentage, the genistein concentration began to increase. At 20°C both isoflavones rose until the end of the experiment, reaching values similar to the sample at 10°C. A temperature of 30°C was deleterious to grape isoflavones. A discussion on the changes in isoflavones related to temperature and time is reported.
将白葡萄格雷切托（Grechetto）品种的葡萄串在 10、20 和 30°C、相对湿度 45%和 1.5m/s 的强制空气通风条件下进行脱水。在不同减重阶段（10%、20%、30%和 40%）研究了脱水对化学和代谢变化的影响：在 10 和 20°C，葡萄颜色随着脱水而趋于变绿，但在 30°C，在最后一次采样时，颜色变暗。所有样品的酸度都降低了，而糖分增加了。在 10°C 时，总酚含量增加，直到达到 30%的减重，然后下降，而在 20 和 30°C 时，浓度立即下降。叶黄素和β-胡萝卜素（分别为 68 和 58mg/kg 干重）的含量（代表总类胡萝卜素的 80%）在达到 30%的减重之前没有明显变化，此时在 30°C 下，叶黄素的含量增加，而在 10 和 20°C 下，含量明显下降。大豆甙元在 10°C 时从约 150μg/kg 干重显著上升至 20%减重时的 1434μg/kg 干重，然后下降；在相同的减重百分比下，染料木素浓度开始增加。在 20°C 时，两种异黄酮都上升到实验结束，达到与 10°C 样品相似的值。30°C 的温度对葡萄异黄酮有害。报告了关于温度和时间对异黄酮变化的讨论。
