Question

Name the membrane process which uses membranes with larger pores to allow permeation of many organic compounds such as sugars

• A. Reverse osmosis
• B. Ultrafiltration
• C. Nanofiltration
• D. Microfiltration

Hint:

Membrane Separation: ULTRAFILTRATION allows permeation of SUGARS (Lactose) and minerals while retaining and concentrating PROTEINS.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Ultrafiltration selectivity in dairy processing: Ultrafiltration (UF, pore size 0.01--0.1 $\mu ext{m}$, MWCO 10--100 kDa) retains colloidal caseins and globular whey proteins in the retentate while allowing smaller organic molecules like lactose sugars, non-protein nitrogen, and soluble minerals to permeate freely.
Key Formula or Approach:
\[ \text{Ultrafiltration (UF) Separation: } \underbrace{\text{Proteins (Caseins, } \beta\text{-Lg, } \alpha\text{-La)}}_{\text{Retentate (Concentrated)}} \quad \longleftrightarrow \quad \underbrace{\mathbf{Lactose \text{ (Sugar)} + \text{Minerals} + \text{Water}}}_{\mathbf{Permeate \text{ (Freely Permeates)}}} \]

Step 2: Detailed Explanation:
In dairy membrane fractionation and whey protein concentration:
- Ultrafiltration (UF) (B): A selective pressure-driven membrane process operating at intermediate pressures ($200 - 800\text{ kPa}$):
1. UF membranes possess pore sizes ($0.01 - 0.10\;\mu\text{m}$, MWCO $10,000 - 50,000\text{ Da}$) that are large enough to allow free permeation of smaller organic molecules—predominantly lactose sugar (MW 342 Da), urea, peptides, and soluble minerals into the permeate stream.
2. Simultaneously, UF tightly retains high-molecular-weight macromolecules (micellar casein and whey proteins) in the retentate.
3. It is universally used for manufacturing Whey Protein Concentrates (WPC-34 to WPC-80) and in standardized cheese milk protein standardization.

Step 3: Final Answer:
Therefore, the membrane process is Ultrafiltration, corresponding to option (B).