Vacuum-Assisted Block Freeze Concentration Studies in Cheese Whey and Its Potential in Lactose Recovery

Area of Science:

• Food Science and Technology
• Chemical Engineering
• Dairy Processing

Background:

• Block freeze concentration (BFC) is an emerging technology for producing high-quality organoleptic products.
• Low temperatures in BFC preserve product quality.
• Whey, a dairy byproduct, contains valuable lactose that can be recovered.

Purpose of the Study:

• To investigate vacuum-assisted BFC for whey processing.
• To determine the effects of vacuum time, pressure, and initial solids concentration on BFC efficiency.
• To evaluate lactose recovery yield and concentration index in whey.

Main Methods:

• Vacuum-assisted block freeze concentration (BFC) was applied to whey.
• Key process variables studied: vacuum time, vacuum pressure, and initial solids concentration.
• Solute yield (Y) and concentration index (CI) were measured to assess efficiency.

Main Results:

• Vacuum time, pressure, and initial solids concentration significantly impacted solute yield (Y) and concentration index (CI).
• Optimal conditions for high solute yield (Y): 10 kPa, 7.5 °Bx, and 60 min.
• Optimal conditions for high concentration index (CI): 10 kPa, 7.5 °Bx, and 20 min.
• Over 70% lactose recovery (Y) achieved in a single step across three whey types.
• Lactose concentration index (CI) exceeded soluble solids CI.

Conclusions:

• Vacuum-assisted BFC is a viable technology for efficient lactose recovery from whey.
• The process can achieve high lactose recovery rates (>70%) in a single step.
• This technology presents an interesting alternative for valorizing whey byproducts.