Ceramic Membrane for Syrup Purification in Sugar Industry

Soybean protein enzymatic hydrolysis is a common process for producing soybean peptides. After protease hydrolysis, the feed liquid is a complex mixture. Apart from expected small‑molecule active peptides, there remain unhydrolyzed macromolecular proteins, denatured protein aggregates, polysaccharides and fine insoluble residues. If these impurities are not removed, finished peptide powder will have poor solubility, high turbidity and unstable shelf‑life performance.

Centrifugation and acid precipitation are widely‑used traditional purification methods in workshops. Centrifugal force removes partial solid particles but has limited capability for separating dissolved macromolecular protein. Acid precipitation relies on pH adjustment to make protein precipitate out. Yet the process may cause peptide co‑precipitation, lowering final product yield. In addition, pH modification brings extra salt content into solution and increases burden for subsequent desalting treatment.

Ultrafiltration membrane system performs physical fractionation based on molecular weight difference. Choosing proper MWCO membrane element can retain macromolecular undigested protein and protein aggregates in retentate stream. Small‑molecule soybean peptides go through membrane as permeate stream. The whole separation process runs under mild temperature condition without chemical precipitation agents. It avoids introducing extra acid or alkali for precipitation step.

Membrane fouling is the main challenge during continuous hydrolysis liquid processing. Denatured protein and polysaccharide tend to adhere to membrane surface and form fouling layer, which decreases permeate flux. Effective pre‑treatment is essential to eliminate coarse suspended solids before entering ultrafiltration unit. Strict control over feed concentration can mitigate severe fouling. Scheduled CIP cleaning with alkaline and acidic solution is required to remove organic deposits and recover membrane flux for long‑term production.

For soybean peptide manufacturers, ultrafiltration fractionation brings multiple benefits. It improves purity and water‑solubility of soybean peptide products. It reduces peptide loss compared with acid precipitation process and raises overall yield. The membrane equipment can work in continuous cross‑flow mode and connect with follow‑up nanofiltration concentration and spray drying units.

Ultrafiltration alone cannot complete full production workflow. After ultrafiltration fractionation, permeate peptide solution usually needs nanofiltration for concentration and desalination. Combined membrane process of ultrafiltration plus nanofiltration becomes a mature solution for plant peptide industry. With the development of membrane material technology, ultrafiltration will be more broadly applied in various enzymatic hydrolysate purification fields.