Coupling Ultrafiltration-Based Processes to Concentrate Phenolic Compounds from Aqueous Goji Berry Extracts

Area of Science:

• Food Science
• Chemical Engineering
• Biotechnology

Background:

• Goji berries (Lycium barbarum L.) are rich in antioxidant compounds, particularly phenolic compounds.
• Efficient extraction and purification methods are needed to isolate these valuable compounds from complex matrices.
• Membrane technology offers a promising approach for selective separation and concentration.

Purpose of the Study:

• To investigate a membrane-based process for purifying and concentrating antioxidant compounds from aqueous Goji berry extracts.
• To evaluate the performance of ultrafiltration (UF) membranes with varying molecular weight cut-off (MWCO) and transmembrane pressure (TMP).
• To assess the impact of diafiltration on the purification efficiency of phenolic compounds.

Main Methods:

• Aqueous Goji berry extract was initially clarified using hollow fiber UF membranes.
• Three UF flat sheet polyamide membranes (1000-3500 Da MWCO) were tested for purification and concentration.
• The effects of MWCO and TMP on membrane performance (productivity, selectivity) were evaluated.
• Diafiltration was incorporated using a spiral-wound configuration with the optimal membrane.

Main Results:

• The 2500 Da membrane showed superior performance with a lower fouling index and higher cleaning efficiency.
• This membrane achieved higher rejection of phenolic compounds ( >50%) and lower rejection of carbohydrates ( <30%).
• Incorporating diafiltration enhanced phenolic compound purification in the retentate and sugar concentration in the permeate.

Conclusions:

• Membrane filtration, particularly using a 2500 Da UF membrane, is effective for purifying and concentrating phenolic antioxidants from Goji berry extract.
• The process allows for selective separation, retaining valuable phenolic compounds while reducing carbohydrate content.
• Diafiltration further refines the separation process, offering potential for high-purity antioxidant fractions.