Nanofiltration Membrane Low-Temperature Concentration Technology for Botanical Extract Processing

Plant extracts are rich in natural active substances such as polyphenols, flavonoids, terpenoids and glycosides. Most of these functional ingredients are heat-sensitive and easily degraded under high-temperature and aerobic conditions. In traditional industrial production, after clarification and filtration, the dilute extract needs multi-stage vacuum evaporation to increase solid content. However, continuous high-temperature boiling changes the molecular structure of natural ingredients, destroys original biological activity, and causes irreversible browning and flavor deterioration of plant liquid. At the same time, the traditional evaporation process consumes a large amount of steam and cooling water, resulting in high energy consumption and high production cost for extract enterprises.

In addition to thermal damage defects, traditional concentration equipment cannot screen and separate soluble heterologous substances. A large number of tiny inorganic salts, residual organic acids and miscellaneous sugars remain in the concentrated liquid, which increase the ash content of finished powder, reduce product solubility, and cause moisture absorption and deterioration during storage. For high-end plant extracts used in cosmetics, functional food and pharmaceutical raw materials, traditional thermal concentration seriously restricts product grade and market competitiveness.

Nanofiltration membrane technology completely changes the traditional thermal concentration mode of plant extracts. Relying on precise molecular weight screening and charge selective separation, the nanofiltration membrane efficiently intercepts medium and macromolecular effective active ingredients, allowing water molecules and part of small-molecule impurity ions to penetrate the membrane and discharge. The whole concentration process is completed under normal temperature and closed environment, without boiling, phase change or thermal degradation, which maximally retains the activity, color and natural flavor of plant active substances.

Different from the single concentration effect of evaporators, nanofiltration realizes simultaneous concentration and fine purification. While reducing the liquid volume and improving the solid content of extracts, it removes residual small-molecule salts and heterozygous impurities, effectively reducing product ash content and improving powder fineness and solubility. The cross-flow circulating operation mode avoids membrane surface blockage caused by plant colloids and micro-impurities, maintains stable filtration flux during long-term concentration, and meets the requirements of large-scale continuous industrial production.

In the standardized plant extract production process, nanofiltration equipment is matched with ultrafiltration clarification process. After ultrafiltration removes macromolecular colloids, proteins and pectin impurities, the clear dilute extract enters the nanofiltration system for low-temperature concentration. Compared with the traditional process of “evaporation + drying”, the membrane concentration process greatly reduces the water treatment volume of subsequent drying equipment, significantly reduces drying energy consumption, and improves production efficiency.

The fully automatic membrane system supports 24-hour uninterrupted operation, with adjustable concentration multiple, operating pressure and circulating flow, which can adapt to different types of plant materials and customized product indicators. Equipped with perfect CIP online cleaning system, the equipment can quickly eliminate organic dirt and pigment deposition, ensure stable separation performance for a long time, and realize consistent quality of each batch of products. The permeate water produced during the process is clean and recyclable, which can be reused for raw material leaching and workshop flushing, realizing energy-saving and water-saving clean production.

With the upgrading of the natural plant extract industry, low-temperature, green and high-precision processing has become the mainstream development trend. Nanofiltration low-temperature concentration technology effectively solves the industry pain points of high energy consumption, serious active ingredient loss and unstable product quality in traditional thermal concentration. It helps botanical processing enterprises improve product added value, reduce production costs and realize intelligent and green industrial upgrading.