Plaza Andrea, Romero Julio, Silva Wladimir, Morales Elizabeth, Torres Alejandra, Aguirre María J
Laboratory of Membrane Separation Processes (LabProSeM), University of Santiago de Chile (USACH), Chile.
Laboratory of Membrane Separation Processes (LabProSeM), University of Santiago de Chile (USACH), Chile
Food Sci Technol Int. 2014 Oct;20(7):501-10. doi: 10.1177/1082013213494900. Epub 2013 Jul 29.
Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH < 1 was treated by membrane extraction at 25 ℃. This operation is based on a hydrophobic Hollow Fiber Contactor, which separates the acidified red wine in the shell side and a diluted aqueous sodium hydroxide solution as receiving solution into the lumenside in countercurrent. Sulfite and bisulfite in the acidified red wine become molecular SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability.
亚硫酸盐[化学式：见原文]或二氧化硫（SO₂）是一种广泛用于水果及其衍生产品的防腐剂。本研究旨在提出一种膜接触器工艺，用于从葡萄酒中选择性去除和回收SO₂，以实现其可靠定量。目前，抽吸法和里珀法对红葡萄酒中亚硫酸盐含量的定量分析存在困难，因为它们分别涉及稀释化合物的蒸发步骤和比色测定。因此，目前在液体食品工业中还没有一种廉价且准确的方法用于连续监测SO₂。初始pH<1的红葡萄酒在25℃下进行膜萃取处理。该操作基于疏水性中空纤维接触器，它将壳侧的酸化红葡萄酒与作为接收溶液的稀释氢氧化钠水溶液在管腔内逆流分离。酸化红葡萄酒中的亚硫酸盐和亚硫酸氢盐变成分子态SO₂，通过充满气体的膜孔蒸发。因此，SO₂被困在无色溶液中，膜接触器控制其转移，减少了传统方法中产生的实验误差。使用已知浓度值[化学式：见原文]的模型溶液进行的实验结果表明，4分钟后平均萃取率为98.91%。另一方面，使用同一系统对两种智利赤霞珠葡萄酒进行分析，以量化游离和总亚硫酸盐的含量。结果表明，这些方法与所提出的技术之间具有良好的一致性，所提出的技术显示出较低的实验变异性。
