Comparison of reverse osmosis (X‐20, RO‐99) and nanofiltration (NF‐270) membranes in the concentration of hawthorn fruit and anise seed extracts

Abstract

SummaryHawthorn fruit and anise seeds are considered medicinal plants. Both have a long history of medical use, which dates back to traditional medicine and has been supported by scientific studies that have demonstrated their effectiveness in many areas. Through pressure‐driven membrane processing, this study describes an environmentally friendly approach to concentrating bioactive compounds in extracts of these plants. Two reverse osmosis membranes (RO‐99 and X‐20) and one nanofiltration membrane (NF‐270) were tested. The composition of initial extracts and the resulting streams (permeates and concentrates) was compared, and the process efficiency was assessed based on the flux profiles and the contents of examined compounds such as antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC). For the concentration of these extracts, the X‐20 membrane presented the most effective results, showing the lowest overall decrease in permeability. RO99 and NF‐270 followed this. In addition, X‐20 shows the lowest fouling index, followed by RO‐99, and both exhibit reversible contamination. In contrast to the NF‐270 membrane, the contamination was irreversible. Additionally, TPC increased 20 and 18‐fold, respectively, in the final retentate of anise seed extract and hawthorn fruit extract. TFC increased 8‐fold for both extracts compared to the initial content. Furthermore, the process using X‐20 showed an improvement of around 12‐fold for anise extracts, 15‐fold for hawthorn extracts for antioxidant activity by FRAP, and around 9‐fold by the DPPH method for both anise and hawthorn extracts. The phenolic and flavonoids compounds were detected at values <0.4 mg/g in the permeate from X‐20.