SDS-PAGE in Food Science: Elevating Protein Insight and Product Integrity
SDS-PAGE in Food Science: Elevating Protein Insight and Product Integrity
In today’s food industry, ingredient quality and transparency are paramount for maintaining standards and consumer trust. As consumers increasingly seek high-protein options, selecting the right protein ingredients becomes even more critical. One powerful method for evaluating proteins is Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE).
Originally developed by molecular biologists, SDS-PAGE is now widely used in food science to assess proteins in everything from meat and dairy to plant-based products. Its ability to separate proteins based on molecular weight makes it an indispensable tool for research and development and quality assurance.
What is SDS-PAGE?
SDS-PAGE, short for sodium dodecyl sulfate polyacrylamide gel electrophoresis, is a method used to separate proteins by their molecular weight. First, samples are prepared for analysis. Sodium dodecyl sulfate (SDS) is used to denature proteins and coat them in a negative charge proportional to their size. Proteins may also be exposed to a reducing agent, such as β-mercaptoethanol, to break apart disulfide bonds.
Second, prepared samples are loaded onto a gel and an electric field with positive and negative electrodes. The proteins, which are negatively charged due to the SDS, migrate towards the positive electrode. However, migration is much easier for the smaller proteins, and they can travel further than the larger ones in the same amount of time. This is how the protein bands are separated.
Finally, after the proteins have been separated, the gel is stained and protein bands between approximately 10 and 250 kDa can be visualized. Gels can be scanned and run through specialized software to obtain optical densitometry data, which can estimate molecular weights and band intensity.
Food Industry Applications for SDS-PAGE
Here are a few ways we have used SDS-PAGE to support product development efforts at Eurofins Product Development and Innovation:
- Assessing process impact – processes such as enzymatic or chemical hydrolysis and exposure to heat can affect the molecular weight distribution of proteins. This can also affect performance of ingredients in the end application. SDS-PAGE can be used to visualize the effect of these processes on molecular weight distribution
- Supply chain – whether switching suppliers or building supply chain redundancy, SDS-PAGE can let you assess how similar two protein ingredients are to each other based on molecular weight and ability to resolve protein bands
- Product characterization – SDS-PAGE analysis provides a valuable approach for understanding reference products, ingredient selection and process history (e.g., use of native proteins or hydrolyzed versions).
- Investigate ingredient and product quality issues – Lot-to-lot variability may affect how an ingredient performs in an application, and batch-to-batch differences may affect a finished product. In cases where large differences are noted, SDS-PAGE can be a helpful tool to determine if differences are due to the proteins or other ingredient components
- Investigate potential adulteration –SDS-PAGE can help determine if the sample is potentially adulterated by comparing the banding pattern to a known reference
- Stability studies – SDS-PAGE can help assess changes in protein integrity during product shelf life (e.g., enzymatic hydrolysis)
- Process control – SDS-PAGE can help define complex processes such as fermentation and aging (e.g., cheese aging involves proteolysis of dairy proteins to a variety of peptides of different molecular weights, with major flavor contributions).
Turning Protein Profiles into Brand Confidence
As experienced food scientists, the team at Eurofins Product Development and Innovation has the technical expertise necessary to interpret SDS-PAGE results and translate them into strategic insights that enhance product quality, ensure consistency, and reinforce consumer confidence. In addressing protein-related challenges, SDS-PAGE serves as a reliable and effective analytical tool.
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Additional Resources
Case Study: High Protein Yogurt Innovation
Understanding Protein Quality: How PDCAAS Shapes Nutritional Claims
