Dushkova Mariya, Mihalev Kiril, Dinchev Angel, Vasilev Kiril, Georgiev Diyan, Terziyska Margarita
Department of Food Preservation and Refrigeration Technology, University of Food Technologies, 26 Maritza Blvd., 4002 Plovdiv, Bulgaria.
Research Institute of Mountain Stockbreeding and Agriculture, 281 Vasil Levski Str., 5600 Troyan, Bulgaria.
Membranes (Basel). 2022 Oct 23;12(11):1032. doi: 10.3390/membranes12111032.
The aim of the present work was to study the potential of ultrafiltration with three polyacrylonitrile membranes (1, 10, and 25 kDa) to concentrate polyphenolic antioxidants in apple juice and extract. The permeate flux, total polyphenols, polyphenolic profile, phenolic acid content, and total antioxidant capacity were determined using the FRAP and DPPH tests, the content of water-soluble proteins during ultrafiltration was established, and the concentration factors and rejections were determined. The permeate flux decreased by increasing the volume reduction ratio and decreasing the molecular weight cut-off of the membranes. The concentration factor and rejection of polyphenolics increased with the increase in the volume reduction ratio (VRR) for all membranes and both liquids. The concentration and rejection effectiveness of the 1 kDa membrane was higher than those observed for 10 and 25 kDa during the ultrafiltration of the apple extract, while these values were comparable for 1 and 10 kDa during the ultrafiltration of the apple juice. The concentration factors and rejections of total polyphenols were higher in the extract than in the juice. Chlorogenic acid was the main compound in the polyphenol profile of apple juice. The total content of phenolic acids, determined by using HPLC, increased by 15-20% as a result of the membrane concentration, but the separation process did not significantly change the ratio between the individual compounds.
本研究的目的是探讨使用三种聚丙烯腈膜（1、10和25 kDa）进行超滤，以浓缩苹果汁和提取物中多酚类抗氧化剂的潜力。使用FRAP和DPPH测试测定渗透通量、总多酚、多酚谱、酚酸含量和总抗氧化能力，确定超滤过程中水溶性蛋白质的含量，并测定浓缩因子和截留率。随着体积减少率的增加和膜截留分子量的降低，渗透通量下降。所有膜和两种液体的多酚类物质的浓缩因子和截留率均随着体积减少率（VRR）的增加而增加。在苹果提取物的超滤过程中，1 kDa膜的浓缩和截留效果高于10 kDa和25 kDa膜，而在苹果汁的超滤过程中，1 kDa和10 kDa膜的这些值相当。提取物中总多酚的浓缩因子和截留率高于果汁。绿原酸是苹果汁多酚谱中的主要化合物。通过HPLC测定，膜浓缩后酚酸的总含量增加了15%-20%，但分离过程并未显著改变各化合物之间的比例。
