Costantini Vincenzo, Bellincontro Andrea, De Santis Diana, Botondi Rinaldo, Mencarelli Fabio
Department of Food Science and Technology, University of Viterbo, via S. Camillo de Lellis, snc 01100 Viterbo, Italy.
J Agric Food Chem. 2006 May 3;54(9):3334-40. doi: 10.1021/jf053117l.
Malvasia (Vitis vinifera L.) grapes were harvested at 17.8% of soluble solids content (SSC) and placed inside an innovative dehydration room where temperature, relative humidity, and air flow were maintained, respectively, at 15 degrees C, 40%, and 1-1.5 m s(-1). Weight loss of bunches reached approximately 33% in 29 days. SSC increased inversely proportionally with the weight decrease, reaching at the end of experiment 23%. Abscisic acid (ABA) increased rapidly from around 29 to 80 microg g(-1) of dry weight at 11.7% of bunch weight loss and then declined gradually. Lipoxygenase (LOX) showed the same behavior as ABA, whereas alcohol dehydrogenase (ADH), read in the way of ethanol oxidation, increased continuously when the weight loss reached approximately 19.5%. In parallel with the activity of LOX, C6 compound [hexanal, hex-1-enol, (E)-hex-2-enal] concentrations reached a peak at 11.7% of weight loss, whereas ethanol and acetaldehyde increased with the increase of ADH and successively decrease and ethyl acetate increased. Proline increased initially as ABA and successively with the increase of ADH, 5.3-fold increase versus 4.2-fold increase of proteins. Postharvest dehydration of Malvasia grapes shows a biphasic pattern: a first metabolic stress response up to 11.7% of bunch weight loss and a second stress response beyond 19.5% of weight loss. The metabolic mechanism of these postharvest water stress responses is discussed.
马尔瓦西亚（Vitis vinifera L.）葡萄在可溶性固形物含量（SSC）为17.8%时采收，并放置在一个创新的脱水室中，该脱水室内温度、相对湿度和气流分别维持在15℃、40%和1 - 1.5 m s⁻¹。在29天内，葡萄串的重量损失达到约33%。SSC与重量减少成反比增加，在实验结束时达到23%。脱落酸（ABA）在葡萄串重量损失11.7%时，从约29迅速增加到80 μg g⁻¹干重，然后逐渐下降。脂氧合酶（LOX）表现出与ABA相同的行为，而以乙醇氧化方式测定的乙醇脱氢酶（ADH）在重量损失达到约19.5%时持续增加。与LOX的活性平行，C6化合物[己醛、己-1-烯醇、（E）-己-2-烯醛]浓度在重量损失11.7%时达到峰值，而乙醇和乙醛随着ADH的增加而增加，随后下降，乙酸乙酯增加。脯氨酸最初与ABA一样增加，随后随着ADH的增加而增加，脯氨酸增加了5.3倍，而蛋白质增加了4.2倍。马尔瓦西亚葡萄的采后脱水呈现出双相模式：在葡萄串重量损失达到11.7%之前为第一次代谢应激反应，在重量损失超过19.5%之后为第二次应激反应。本文讨论了这些采后水分胁迫反应的代谢机制。
