For infant lactose intolerance intervention and daily lactase supplementation, acid lactase and neutral lactase are two common enzyme preparations. They differ significantly in terms of source safety, working conditions, and labeling & application. Understanding these differences correctly is key to selecting the right product.
1. Source and Safety
Acid Lactase: Primarily derived from Aspergillus oryzae and Aspergillus niger, it has U.S. FDA "GRAS" certification. It can be directly used as a dietary supplement, suitable for lactose intolerance supplementation in populations such as infants and adults.
Neutral Lactase: Mainly sourced from yeast (Kluyveromyces lactis), it is mostly used in industrial dairy production (e.g., lactose-free milk, ice cream, cheese). After hydrolyzing lactose, it undergoes inactivation to ensure no residual activity in final products.
2. Working Conditions
Acid Lactase: Its stable activity range is well-adapted to the human physiological environment. The conditions for determining its activity are 37°C and pH 4.5; however, practical studies have shown that acid lactase can maintain 80% activity in the range of pH 3–8 and 40–60°C. Therefore, it is suitable not only for adult gastric acid environments but also for children's gastric acid environments.
Neutral Lactase: Its stable activity range is more suited for industrial production. The conditions for determining its activity are 30.0°C ± 0.1°C and pH 6.50. It maintains stable activity in a neutral environment but has poor tolerance to gastric acid, making it difficult to retain activity in the human stomach. When supplied to consumers as a lactase preparation, its usage instructions typically specify that it should be added to milk, shaken well, and then refrigerated for a certain period before consumption.
3. Labeling and Application
Acid Lactase: Labeled with "ALU" (Acid Lactase Unit), it is mainly used for infant lactose intolerance supplementation and adult daily lactase supplementation. It features high safety and flexible usage, suitable for on-demand feeding and daily diets.
Neutral Lactase: Labeled with "NLU" (Neutral Lactase Unit), it is mostly used in industrial production of lactose-free dairy products. It is suitable for large-scale industrial use but not recommended as a direct oral dietary supplement.
Acid lactase and neutral lactase are not "superior or inferior" but "functionally different." When choosing, consider source safety, condition adaptability, and needs.By accurately distinguishing the two types through enzyme activity unit labeling, you can choose a lactase product that truly meets your needs.