Soy Protein Peptide Solution Purification by Membrane Separation Technology

Soy protein peptide is a high‑value small‑molecule active substance hydrolyzed from soybean protein, widely applied in health food, functional beverage, cosmetics and bio‑fermentation industries. However, crude soy peptide stock liquid usually contains macromolecular proteins, suspended particles, pigments and miscellaneous polysaccharides, which lead to dark color, poor clarity and unstable product quality. Traditional filtration methods such as plate‑frame filter press can only remove visible insoluble impurities, and fail to separate macromolecular hetero‑proteins and soluble pigments, limiting the application of final peptide products.

Membrane separation technology offers an efficient physical separation route for soy protein peptide purification and clarification, without adding chemical reagents and high‑temperature heating. It retains bio‑activity of target small‑molecule peptides.

As shown in the comparison sample photo:

• Raw peptide feed liquid: Dark brown crude hydrolysate, loaded with residual large protein molecules, pigments and colloidal impurities. High turbidity and dark color restrict downstream formulation.

• Permeate filtrate after membrane treatment: Light yellow clear liquid. Most macromolecular impurities and chromogenic substances are intercepted by membrane elements, while target small‑molecule soy protein peptides pass through the membrane channel. Obvious improvement on transparency and sensory property.

Core process selection for soy protein peptide

1. Ultrafiltration for impurity removal & clarification

   Select proper molecular weight cutoff (MWCO) ultra‑filtration membrane. It intercepts invalid macromolecular proteins, colloids and suspended solids, lets small‑molecule soy protein peptides go through. This step mainly achieves de‑contamination, turbidity reduction and clarification.

2. Nanofiltration for desalination & concentration

   After ultrafiltration, nanofiltration membrane can further concentrate peptide components, remove inorganic salt and partial pigment. It increases peptide concentration and reduces ash content, to meet standards of food‑grade soy peptide raw material.