Microfiltration (MF) Membranes: With pore sizes ranging from 0.1–10 μm, MF membranes are primarily used to remove large particles such as pulp fibers, yeast, and bacteria. They are the most widely applied membrane type in juice clarification, suitable for preliminary purification of citrus, apple, and grape juice.

Ultrafiltration (UF) Membranes: Featuring smaller pores (1–100 nm), UF membranes can further separate colloids, soluble proteins, and high-molecular-weight pectins. UF-clarified juice exhibits superior transparency and stability, making it ideal for premium products like clear apple juice and peach juice.

Nanofiltration (NF) Membranes: Though less commonly used for clarification alone, NF membranes (pore size <1 nm) are occasionally employed in combination with UF to remove trace colloids and adjust sugar content, enhancing juice quality and consistency.

Superior Clarification Effect: Produces juice with high transmittance (usually >95%) and stable quality, free from turbidity and sediment during storage.

Retention of Nutrients: Operates under low-temperature conditions, minimizing the loss of heat-sensitive nutrients such as vitamin C, polyphenols, and antioxidants.

No Chemical Additives: Avoids the use of coagulants, flocculants, or clarifiers (e.g., bentonite, gelatin), ensuring "clean label" products that meet consumer demands for natural and healthy food.

High Efficiency and Energy Saving: Continuous operation with simple process flow, reducing water and chemical consumption compared to traditional methods.

Improved Shelf Life: Removes microorganisms and spoilage-causing substances, extending the juice’s shelf life without excessive thermal processing.

Apple Juice: Ultrafiltration membranes (molecular weight cutoff: 10–50 kDa) are commonly used to remove pectins and proteins. Industrial data shows that UF-clarified apple juice retains over 90% of vitamin C and polyphenols, with a shelf life extended to 12 months under refrigeration.

Grape Juice: Microfiltration (ceramic membranes, pore size 0.2 μm) effectively separates grape skins, seeds, and colloidal particles, producing clear juice that maintains the characteristic color and aroma of grapes. This process is widely used in the production of grape juice concentrates and wine base materials.

Citrus Juice: Combination of microfiltration and ultrafiltration addresses the challenge of high pectin content in citrus juice. The integrated process removes turbidity-causing substances while retaining limonene and other flavor compounds, resulting in clear orange or lemon juice with natural taste.

Tropical Fruit Juices (Mango, Pineapple): Ultrafiltration membranes resistant to organic acids are used to clarify viscous tropical fruit juices. This technology solves the problem of sedimentation caused by protein-pectin interactions, improving product stability.

Membrane Fouling: Accumulation of proteins, pectins, and colloids on the membrane surface reduces flux and increases operating costs. Current solutions include optimizing operating parameters (e.g., cross-flow velocity, TMP), periodic chemical cleaning (using citric acid or sodium hydroxide), and membrane surface modification.

High Initial Investment: The cost of membrane modules and equipment is relatively high, which may limit adoption by small and medium-sized enterprises.

Development of Anti-Fouling Membranes: Novel membranes with hydrophilic, anti-adhesive surfaces (e.g., modified ceramic membranes, graphene oxide composite membranes) to reduce fouling and extend service life.

Integration with Other Technologies: Combining membrane filtration with processes such as pulsed electric field (PEF) or enzyme treatment to improve clarification efficiency and reduce fouling.

Process Intensification: Design of compact, energy-efficient membrane systems (e.g., hollow fiber membrane modules) to lower operating costs and enhance scalability.

Application Expansion: Extending membrane filtration to the clarification of functional juices (e.g., berry juices rich in antioxidants) and plant-based beverages, meeting the growing demand for high-value products.