Related Experiment Video

Updated: Sep 20, 2026

Functional Site-Directed Fluorometry in Native Cells to Study Skeletal Muscle Excitability
12:26

Functional Site-Directed Fluorometry in Native Cells to Study Skeletal Muscle Excitability

Published on: June 2, 2023

Effect of low and high pH treatment on the functional properties of cod muscle proteins

Hordur G Kristinsson1, Herbert O Hultin

  • 1Laboratory of Aquatic Food Biomolecular Research, Aquatic Food Products Program, Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida 32611, USA. hgkristinsson@mail.ifas.ufl.edu

Journal of Agricultural and Food Chemistry
|August 9, 2003
PubMed

Insights

Altering the pH of cod myosin and myofibrillar proteins improves their functional properties, like emulsification and gel strength. Alkali treatment showed the greatest improvement, linked to partial protein unfolding.

Area of Science:

  • Food Science
  • Protein Chemistry
  • Seafood Processing

Background:

  • Myosin and myofibrillar proteins are key components of fish muscle.
  • Understanding their functional properties is crucial for seafood product development.
  • Previous research suggests pH treatment can alter protein functionality.

Purpose of the Study:

  • To investigate the impact of high and low pH treatments on cod myosin and myofibrillar protein functionality.
  • To correlate changes in functional properties with protein structural modifications.
  • To determine the optimal pH treatment for enhancing protein functionality.

Main Methods:

  • Cod myosin and myofibrillar proteins were treated at pH 11 and 2.5, then readjusted to pH 7.5.
  • Solubility, emulsification properties, gel strength, and thermal properties were analyzed.
  • Surface hydrophobicity and surface/interfacial activity were measured.

Main Results:

  • pH-treated myofibrillar proteins exhibited increased solubility across various ionic strengths.
  • Acid and alkali treatments enhanced emulsification properties of both myosin and myofibrillar proteins.
  • Acid and alkali treatments improved gel strength in myosin but not significantly in myofibrillar proteins.
  • Treated proteins showed lower unfolding and gelling temperatures, indicating reduced conformational stability.

Conclusions:

  • Partial unfolding of cod myosin and myofibrillar proteins via acid and alkali treatment can enhance functional properties.
  • Alkali treatment yielded the most significant improvements in functionality.
  • Enhanced functionality is directly linked to the degree of myosin partial unfolding during pH treatment and refolding.

More Related Videos

Assessing Functional Metrics of Skeletal Muscle Health in Human Skeletal Muscle Microtissues09:30

Assessing Functional Metrics of Skeletal Muscle Health in Human Skeletal Muscle Microtissues

Published on: February 18, 2021

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles14:02

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Published on: November 1, 2012

Related Concept Videos

Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
What are Proteins?01:28

What are Proteins?

Proteins are polymers of amino acids linked together by peptide bonds. Proteins and polypeptides are interchangeably used to refer to long chains of amino acids. However, polypeptides have a molecular weight of fewer than 10,000 daltons, while proteins have greater molecular weight.  Polypeptides with less than 20 amino acids are called oligopeptides or simply peptides. Interactions among the constituent amino acid side chains of proteins help them fold into a stable 3-dimensional structure...
Proteins and Amino Acids02:17

Proteins and Amino Acids

Proteins are chains of amino acids that are connected by peptide bonds and folded into a 3-dimensional structure. The side chains of individual amino acid residues determine the interactions among amino acid residues, and ultimately the folding of the protein. Depending on the length and structural complexity, chains of amino acid residues are classified as oligopeptides, polypeptides, or proteins.Amino Acid Residues Are the Building Blocks of ProteinsAn amino acid is a molecule that contains a...
pH Regulation in Cells01:28

pH Regulation in Cells

pH plays a critical role in maintaining normal cellular activities. It helps maintain the structure and function of various proteins, dictates the charge on cellular membranes, and is crucial for metabolic reactions inside the cell. Moreover, cells use the energy from the proton motive force to generate ATP.
Cytosolic pH
Under physiological conditions, the cytosolic pH is slightly more acidic than the extracellular pH. However, cells must prevent further acidification of their cytosol to...
Protein Denaturation01:28

Protein 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...