Louli V, Ragoussis N, Magoulas K
Laboratory of Thermodynamics and Transport Phenomena, School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, 157 80 Athens, Greece.
Bioresour Technol. 2004 Apr;92(2):201-8. doi: 10.1016/j.biortech.2003.06.002.
The recovery process of the phenolic compounds contained in the wine industry by-products and their antioxidant activity were examined in this work. To this purpose, a combined process of liquid and supercritical solvent extraction was employed. At first the effect of various process parameters of the liquid solvent extraction--the type of solvent and the pretreatment of the raw material (composition (skins, seeds, stems) and crushing)--on the antioxidant activity of the extract was examined. It was shown that an extract of a higher antioxidant activity was obtained by using ethyl acetate as solvent and raw material free of stems. These extracts were further treated with supercritical carbon dioxide (SC CO(2)) at various extraction pressures, which resulted in their significant enrichment in phenolic compounds and the improvement of their antioxidant and organoleptic properties, especially at pressures higher than 100 bar. The antioxidant activity of the products was determined by using the Rancimat method, as well as a simple and not time-consuming free radical method. It was proved that both the ethyl acetate extracts and those treated with SC CO(2) had antioxidant activity comparable to that of antioxidants commonly used in industry, that is butylhydroxytoluene (BHT), a synthetic antioxidant, and Rosemary extract, a widely known natural one.
本研究考察了葡萄酒工业副产品中酚类化合物的回收过程及其抗氧化活性。为此，采用了液体和超临界溶剂萃取相结合的工艺。首先，研究了液体溶剂萃取的各种工艺参数——溶剂类型和原料预处理（组成（皮、籽、茎）和破碎情况）——对提取物抗氧化活性的影响。结果表明，以乙酸乙酯为溶剂且原料无茎时可获得抗氧化活性较高的提取物。这些提取物在不同萃取压力下用超临界二氧化碳（SC CO₂）进一步处理，这使得它们在酚类化合物方面显著富集，并且其抗氧化和感官特性得到改善，尤其是在压力高于100巴时。产品的抗氧化活性通过Rancimat法以及一种简单且耗时短的自由基法测定。结果证明，乙酸乙酯提取物和经SC CO₂处理的提取物的抗氧化活性与工业上常用的抗氧化剂相当，即合成抗氧化剂丁基羟基甲苯（BHT）和广为人知的天然抗氧化剂迷迭香提取物。
