Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases

Area of Science:

• Enzymology
• Food Science
• Biotechnology

Background:

• Lactose intolerance affects a significant portion of the global population.
• Enzymatic lactose hydrolysis offers a solution for producing lactose-free dairy products.
• Understanding enzyme kinetics is crucial for efficient industrial applications.

Purpose of the Study:

• To evaluate the influence of enzyme concentration, temperature, and reaction time on lactose hydrolysis.
• To compare the efficacy of Aspergillus oryzae and Kluyveromyces lactis β-galactosidases.
• To determine optimal conditions for complete lactose hydrolysis in milk, cheese whey, and whey permeate.

Main Methods:

• Utilized two commercial microbial β-galactosidases: Aspergillus oryzae and Kluyveromyces lactis.
• Tested enzyme concentrations of 3, 6, and 9 U/mL.
• Evaluated reactions at varying temperatures (10°C, 37°C, 55°C) and reaction times (up to 12 hours) across different dairy matrices.

Main Results:

• Kluyveromyces lactis showed higher efficiency at 10°C compared to Aspergillus oryzae in all matrices, but did not achieve 100% hydrolysis.
• Aspergillus oryzae achieved 100% lactose hydrolysis in whey and permeate at its optimal temperature (55°C) after 12 hours, irrespective of enzyme concentration.
• Complete lactose hydrolysis in milk was achieved with Aspergillus oryzae at 55°C and 12 hours, using enzyme concentrations of 6 and 9 U/mL.

Conclusions:

• Enzyme concentration, temperature, and reaction time are critical parameters for effective lactose enzymatic hydrolysis.
• Aspergillus oryzae is more effective for complete lactose hydrolysis in whey and permeate under optimal conditions.
• Optimized enzymatic hydrolysis using β-galactosidases holds significant potential for the food industry, particularly in producing lactose-free dairy products.