Related Experiment Video
Updated: May 22, 2026
12:12
Transformation of Probiotic Yeast and Their Recovery from Gastrointestinal Immune Tissues Following Oral Gavage in Mice
Published on: February 8, 2016
Structural changes imposed on whey proteins by UV irradiation in a continuous UV light reactor
Eleana Kristo1, Artan Hazizaj, Milena Corredig
1Department of Food Science, University of Guelph, Guelph, Ontario, Canada. ekristo@uoguelph.ca
Journal of Agricultural and Food Chemistry
|May 29, 2012
Summary
UV light alters whey protein structure, increasing thiol groups and forming aggregates. This structural change enhances protein susceptibility to pepsin digestion, impacting food processing.
Area of Science:
- Food Science
- Protein Chemistry
- Biophysical Chemistry
Background:
- Whey proteins are vital in food and nutrition.
- Understanding their structural changes is crucial for processing.
- UV treatment is a potential method for protein modification.
Purpose of the Study:
- To investigate structural modifications in whey proteins under continuous-flow UV irradiation.
- To correlate UV dosage with changes in whey protein physicochemical properties.
Main Methods:
- Continuous-flow UV reactor with controlled flow rates and mixing speeds.
- Analysis of intrinsic fluorescence, surface hydrophobicity, thiol groups, and size-exclusion chromatography.
- Assessment of pepsin hydrolysis susceptibility.
Main Results:
- UV exposure altered tertiary protein structure, indicated by fluorescence and hydrophobicity.
- Increased total and accessible thiol groups in 1% WPI solutions, but not 5%.
- Formation of UV-induced aggregates and oxidized aromatic amino acids (N-formylkynurenine, dityrosine).
Conclusions:
- Continuous-flow UV treatment induces significant structural changes in whey proteins.
- Concentration-dependent effects of UV on thiol group accessibility were observed.
- UV-modified whey proteins exhibit increased susceptibility to enzymatic digestion by pepsin.
Related Concept Videos
01:35Mutations
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:26Physical Methods for Controlling Microbial Growth: Radiation and Filtration
Radiation and filtration are essential tools for microbial control, targeting microorganisms through distinct mechanisms. Radiation eliminates microbes by damaging their DNA, either killing them or inhibiting their growth. Based on wavelength, radiation is classified into two types: nonionizing and ionizing radiation.Non-ionizing radiation, such as UV radiation (200–400 nm), is absorbed by DNA, causing defects that effectively disinfect surfaces, air, and water, including safety cabinets.
01:08Nucleotide Excision Repair
Overview
01:28Protein Denaturation
The function of proteins depends on their native three-dimensional structure, which is dictated by the amino acid sequence of the specific protein. Folding of the polypeptide chain takes place under specific conditions that energetically favor the folded conformation. In contrast, protein denaturation occurs spontaneously under unfavorable conditions that disrupt the integrity of the folded conformation. Thus, the chemical and physical environment of a protein, such as significant changes in pH...