Membrane technologies for the separation and purification of functional oligosaccharides: A review

Functional oligosaccharides have numerous health benefits. They hold considerable promise in the food processing and healthcare sectors. However, oligosaccharides derived from microbial fermentation, chemical decomposition, and enzymatic hydrolysis often contain impurities, necessitating further purification to enhance the quality and economic value of the final product. Among various purification techniques, membrane separation stands out owing to its operational simplicity, low energy requirements, and scalability, making it ideal for industrial applications. Recently, this method has increasingly been used to separate and purify functional oligosaccharides. Microfiltration and ultrafiltration membranes are typically used in the early stages of filtration to remove proteins, bacterial contaminants, and particulates. In contrast, nanofiltration membranes offer higher separation precision, making them preferable for the detailed purification, concentration, and classification of functional oligosaccharides. This review article mainly focuses on the applications of nanofiltration membrane technologies in the processing of typical functional oligosaccharides, such as fructooligosaccharides, galactooligosaccharides, and xylooligosaccharides. Recent advancements in nanofiltration are discussed, and the properties of the feed liquid, operational parameters, and challenges related to membrane fouling are analyzed. This review aims to serve as a comprehensive guide for the efficient separation and purification of functional oligosaccharide membranes, and advocates for the broader implementation of membrane technologies in the food and medical industries.