Symonds P
Ann Nutr Aliment. 1978;32(5):957-68.
We shall distinguish the case of non aromatic organic acids from that one of phenolic acids. In the first one, we have applied to wines a method used for fruit-juices by Palmer and List, 1973. After contact of the wine with a strong acid resin, its is injected on anion exchange resin Aminex A 25 precolumn (formiate form) which retains all the organic acids. The precolumn is washed with water to eliminate neutral components, then connected with the chromatographic column which contains the same resin. The different acids are eluted with a solution of natrium formiate at 70 degrees C. They are detected by differential refractometry (galacturonic, lactic, malic, succinic, tartric acids) and by ultraviolet at 254 nm (shikimic acid). Beside these compounds which are identified by their retention volumes, others not yet attributed peaks are detected. The limits of detection are 2 mg/l for shikimic acid, 30 mg/l for tartric acid and 15 mg/l for the others. Analysis time is about one hour. In the case of phenolic acids, we extract them from wine by diethyl ether after saturation with NaCl or by demixtion. The determination of phenolic acids is done on the ether extract or on the organic layer of the demixtion. Chromatography is obtained on octadecylsilanised column (RP 18) with solvent gradient (from 10% methanol in KH2PO4O,1 M pH 2,1 to 60% methanol in the same buffer) and detection in ultraviolet at 254 nm. The knowledge of recovery of acids by diethyl ether or by demixtion permits to obtain their concentrations in wine. The different so determinated phenolic acids are: gallic, 4 hydroxybenzoic, cafeic, vanillic, syringic and para coumaric acids. We have applied these methods to 32 wines for phenolic acids and 80 wines for non aromatic acids. Some results are presented in the case of 24 wines issued from Gamay and 8 wines from Pinot and it appears that tartric and shikimic acids have more important average concentrations in the former than in the latter.
我们将区分非芳香族有机酸的情况与酚酸的情况。对于前者，我们对葡萄酒应用了帕尔默和利斯特于1973年用于果汁的一种方法。葡萄酒与强酸性树脂接触后，注入阴离子交换树脂Aminex A 25预柱（甲酸根形式），该预柱保留所有有机酸。用清水冲洗预柱以除去中性成分，然后将其与装有相同树脂的色谱柱相连。不同的酸用70℃的甲酸钠溶液洗脱。通过示差折光法（检测半乳糖醛酸、乳酸、苹果酸、琥珀酸、酒石酸）和在254nm处的紫外检测（检测莽草酸）进行检测。除了通过保留体积鉴定的这些化合物外，还检测到其他未归属峰。莽草酸的检测限为2mg/L，酒石酸为30mg/L，其他酸为15mg/L。分析时间约为1小时。对于酚酸，我们用氯化钠饱和后用乙醚从葡萄酒中萃取，或通过分液萃取。酚酸的测定在乙醚萃取物或分液的有机层上进行。在十八烷基硅烷化柱（RP 18）上进行色谱分析，采用溶剂梯度（从0.1M pH 2.1的KH₂PO₄中10%的甲醇到同一缓冲液中60%的甲醇），并在254nm处进行紫外检测。通过乙醚或分液萃取酸的回收率的知识，可以得到它们在葡萄酒中的浓度。如此测定的不同酚酸有：没食子酸、4-羟基苯甲酸、咖啡酸、香草酸、丁香酸和对香豆酸。我们将这些方法应用于32种葡萄酒以检测酚酸，80种葡萄酒以检测非芳香族酸。给出了24种佳美葡萄酒和8种黑皮诺葡萄酒的一些结果，结果表明，酒石酸和莽草酸在前一种葡萄酒中的平均浓度比后一种葡萄酒中的更高。
