Production of Lactose-Free Milk Products

After successful completion of this session, participants should be able to:

Explain lactose intolerance: Define what lactose intolerance is and why it occurs.
Understand lactose-free production: Describe how lactose-free milk is produced industrially in detail.
Identify technologies: Name different technologies for lactose removal and list their advantages and disadvantages.
Nutritive strategies: Point out strategies to affect the nutritive value of lactose-free products via processing.
Link with eating disorders: Understand the connection between eating disorders and lactose intolerance.

Lactose: A disaccharide sugar present in milk and dairy products.
- Found in all mammalian milks.
- Functions as an ingredient providing texture, binding water, and serving as a carrier for color.
- Commonly found in foods like chocolate, ice cream, margarine, sausages, breaded meats, fish, soups, crisps, puddings, and sweets.

Definition: A condition where the body lacks lactase, the enzyme necessary to digest lactose.
Types of Lactose Intolerance:
- Primary: The most common type, where lactase production decreases with age, typically occurring in late childhood or early adulthood.
- Secondary: Results from injury to the small intestine.
- Developmental: Typically found in premature babies and usually improves over time.
- Congenital: Extremely rare genetic disorder characterized by little or no lactase production.
Prevalence statistics:
- Approximately 65% of adults worldwide experience lactose malabsorption.
- There are regional differences in prevalence:
- North-western Europe: Very low incidence due to high consumption of unmodified milk.
- Central and southern Europe: Higher incidence as milk is primarily consumed as cheese and butter.
- Eastern Europe: Moderate incidence with traditions of fermented milk consumption (Capcanari et al., 2021).

Growth Rate: Notable Compounded Annual Growth Rate (CAGR) estimate of the lactose-free dairy market from 2017 to 2022.
- Total yearly turnover in millions of euros mentioned (Dekker et al., 2019).

Methods of Lactose Removal:
- Filtration: Removes lactose from milk.
- Enzymatic Hydrolysis: Degrades lactose into glucose and galactose.
- Fermentation: Transforms lactose into lactic acid.

Diagrammatic Overview: Illustrates the process of filtration, types of membranes (microfiltration, ultrafiltration), and their roles in separating components of milk.
Combination Techniques: Utilizing a combination of microfiltration and nanofiltration to produce lactose-free milk that retains the original composition and quality.

β-Galactosidase: The enzyme responsible for hydrolyzing lactose, derived from various sources:
- Plant sources such as almonds, peaches, apricots, and apples.
- Animal organs and microorganisms like yeasts, bacteria, and fungi.
- First introduced for dairy applications in 1950 (Van Dam et al.). Commercial availability began in the 1970s, becoming a vital enzyme in food processing.
Production Process Variants:
- Batch Process: Pre-hydrolysis stage.
- Aseptic Process: Post-hydrolysis stage.

Production Effects: The conversion of lactose results in a product with more reducing sugars (glucose and galactose) which may lead to increased sweetness compared to lactose, resulting in potential browning and changes in taste.
Heat and Storage Considerations:
- Mild heat treatment is recommended to preserve quality.
- Proper storage temperature maintains product integrity.
Lactase Side Activities: The presence of unwanted side activities in lactase could affect the sensory quality of products.

Uses in Industry:
- Aroma and stability agent for pharmaceutical products, infant formulas, and in food items such as milk stout and cream stouts.

Process Summary:
- Bacteria produce enzymes to hydrolyze lactose into glucose and galactose, subsequently fermenting glucose into lactic acid.
- Degree of lactose reduction is influenced by fermentation duration.

Current Production Trends: Commercial production of milk using either
- Enzymatic batch hydrolysis or
- Enzymatic batch hydrolysis coupled with membrane filtration is common.
Economic Insights: Enzymatic hydrolysis is more cost-effective than filtration, only incrementing milk prices by 0.06 - 0.08. Transitioning from batch to continuous production could provide economic and environmental benefits.
Future Research Needs: Continuous enzymatic hydrolysis faces challenges in scaling, enzyme recovery, and cleaning processes, necessitating further innovation (Schulz & Rizvi, 2021).

Lactose Intolerance and Eating Disorders:
- Form groups to investigate scientific literature and discuss how eating disorders may affect lactose digestion, including questions on permanence and physiological impacts.
- Hands-on exercises like tasting various lactose and sugar samples to observe differences.