Rózek Aleksandra, Achaerandio Isabel, Almajano María Pilar, Güell Carme, López Francisco, Ferrando Montserrat
Unitat d'Enologia del CeRTA, Generalitat de Catalunya, Departament d'Enginyeria Química, Universitat Rovira i Virgili, Avenida Països Catalans 26, 43007 Tarragona, Spain.
J Agric Food Chem. 2007 Jun 27;55(13):5147-55. doi: 10.1021/jf070427q. Epub 2007 May 31.
Osmotic dehydration was assessed as an operation for supplementing a solid foodstuff (a gel was used as the model food) with grape phenolics from a concentrated red grape must to increase its antioxidant properties. The model food was processed for up to 24 h, and the osmotic pressure was adjusted by diluting the concentrated red grape must. In all conditions tested, low molecular weight phenolics (<or=610 g/mol) and, in particular, trans-caftaric acid, trans-coutaric acid, ferulic acid, coumaric acid, caffeic acid (hydroxycinnamic acids), gallic acid (hydroxybenzoic acids), quercetin, and rutin (flavonols), were quantified in the red grape must and also in the osmo-dehydrated food. Other flavonoids such as (+)-catechin and (-)epicatechin (flavan-3-ols) were detected only in the red grape must. Trolox equivalent antioxidant activity (TEAC) and ferric reducing antioxidant power (FRAP) were determined in the osmo-dehydrated food. Under the conditions that maximized phenolic infusion, the total phenolic content of the gel was close to the values reported in some rich-in-phenolic fruits and vegetables, whereas TEAC was 3 times that of fresh fruit with the highest antioxidant capacity. Regression analysis showed that the individual phenolics analyzed significantly explain the antioxidant capacity of the osmo-dehydrated food.
渗透脱水被评估为一种操作，即从浓缩红葡萄汁中提取葡萄酚类物质，用于补充固体食品（以凝胶作为模型食品），以提高其抗氧化性能。对模型食品进行长达24小时的处理，并通过稀释浓缩红葡萄汁来调节渗透压。在所有测试条件下，均对红葡萄汁以及渗透脱水后的食品中的低分子量酚类物质（≤610 g/mol）进行了定量分析，尤其是反式咖啡酸、反式香豆酸、阿魏酸、香豆酸、咖啡酸（羟基肉桂酸）、没食子酸（羟基苯甲酸）、槲皮素和芦丁（黄酮醇）。其他黄酮类化合物，如（+）-儿茶素和（-）-表儿茶素（黄烷-3-醇）仅在红葡萄汁中检测到。对渗透脱水后的食品测定了Trolox当量抗氧化活性（TEAC）和铁还原抗氧化能力（FRAP）值。在酚类物质注入量最大化的条件下，凝胶的总酚含量接近一些富含酚类的水果和蔬菜中报道的值，而TEAC是具有最高抗氧化能力的新鲜水果的3倍。回归分析表明，所分析的单个酚类物质能够显著解释渗透脱水食品的抗氧化能力。
