Related Experiment Video
Updated: Aug 5, 2026
04:41
Measuring Lactase Enzymatic Activity in the Teaching Lab
Published on: August 6, 2018
Inhibition of bacteria by lactulose preparations
C N Huhtanen1, F W Parrish, K B Hicks
1Eastern Regional Research Center, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118.
Applied and Environmental Microbiology
|July 1, 1980
Summary
Lactulose syrups effectively lower water activity, similar to sucrose. However, lactulose exhibits greater antimicrobial properties, especially when heat-treated, offering enhanced preservation potential.
Area of Science:
- Food science
- Microbiology
- Food preservation
Background:
- Sucrose is a common humectant in food products.
- Lactulose, a functional disaccharide, is gaining interest for its potential prebiotic and health benefits.
- Understanding the antimicrobial properties of lactulose syrups is crucial for food preservation applications.
Purpose of the Study:
- To compare the water activity-lowering effects of lactulose and sucrose syrups.
- To evaluate the antimicrobial efficacy of lactulose syrups against various microorganisms.
- To investigate the impact of heat treatment on the antimicrobial activity of lactulose syrups.
Main Methods:
- Water activity measurements of lactulose and sucrose syrups.
- Microbiological assays using representative foodborne microorganisms.
- Comparative analysis of inhibitory effects based on syrup composition and heat treatment.
Main Results:
- Lactulose and sucrose syrups demonstrated comparable water activity reduction.
- Lactulose syrups exhibited significantly higher inhibition of tested microorganisms compared to sucrose syrups.
- Heat-treated commercial lactulose syrups displayed the most potent antimicrobial activity.
Conclusions:
- Lactulose syrups offer comparable water activity reduction to sucrose syrups.
- Lactulose syrups possess superior antimicrobial properties, particularly when heat-treated, suggesting their utility as effective food preservatives.
- Further research into optimized processing of lactulose syrups could enhance their application in food preservation.
Related Concept Videos
01:20Drugs Affecting GI Tract Motility: Other Laxatives
Laxatives are primarily used to alleviate constipation, a common gastrointestinal disorder characterized by infrequent bowel movements and difficulty passing stools. They work by various mechanisms to increase the volume or frequency of bowel movements. The primary modes of action of laxatives include increasing stool bulk, softening the stool, stimulating intestinal motility, and osmotically drawing water into the intestines.
Osmotic or saline laxatives, like magnesium hydroxide or milk of...
Osmotic or saline laxatives, like magnesium hydroxide or milk of...
01:21Drugs for Treatment of Constipation-Predominant IBS
Pharmacological therapies for IBS-C are designed to alleviate abdominal discomfort and enhance bowel function. In patients with IBS-C, fiber supplements may help soften stools and decrease straining, but may also lead to increased gas production and bloating. Osmotic laxatives like milk of magnesia are frequently used to soften stools and increase stool frequency in IBS-C patients. In addition, two drugs approved for use in severe IBS-C adult cases are linaclotide (Linzess) and lubiprostone...
01:25Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...
01:21Microbiota Modulation by Antibiotics
Antibiotics have revolutionized modern medicine by saving countless lives from bacterial infections. However, their widespread use has inadvertently harmed the delicate balance of the human gut microbiota. The gut microbiota, a complex community of bacteria, archaea, viruses, and fungi, plays a vital role in regulating metabolism, immune responses, and maintaining intestinal health. Antibiotics, especially broad-spectrum types, disrupt this ecosystem by eradicating both harmful and beneficial...
01:23Inhibitors of Gram-positive Cell Wall Synthesis
Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
01:25Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...