Analysis of Capsaicinoids for Scoville Heating Unit (SHU)

The Scoville Heat Scale, devised by Wilbur Scoville in 1912, has long been the benchmark for measuring the pungency of chili peppers and other spicy foods. While the original method was a sensory test, modern laboratory professionals rely on more...

by | Jan 19, 2023

SHU for chili peppers

Capsaicinoid Analysis for Scoville Heating Unit (SHU)

The Scoville Heat Scale, devised by Wilbur Scoville in 1912, has long been the benchmark for measuring the pungency of chili peppers and other spicy foods. While the original method was a sensory test, modern laboratory professionals rely on more objective, precise analytical chemistry methods to determine the Scoville Heat Units (SHUs) of a substance by quantifying its capsaicinoid content.

Capsaicinoids and Pungency

Capsaicinoids are the chemical compounds responsible for the heat sensation in chili peppers, with capsaicin being the most prevalent and pungent of these compounds. The SHU measures the concentration of capsaicinoids, primarily capsaicin and dihydrocapsaicin, which together account for about 90% of the heat sensation.

High-Performance Liquid Chromatography (HPLC)

The analytical standard for measuring capsaicinoids is High-Performance Liquid Chromatography (HPLC). This method separates, identifies, and quantifies the individual capsaicinoid compounds present in a chili pepper extract. The process is as follows:

  1. Sample Preparation: The laboratory professionals prepare a sample by drying and grinding the chili peppers into a fine powder. This powder is then mixed with an organic solvent, typically an alcohol, which dissolves the capsaicinoids.
  2. Chromatographic Separation: The chili extract is injected into the HPLC system. As the sample passes through the column, capsaicinoids are separated based on their chemical affinity to the column material.
  3. Detection and Quantification: As separated capsaicinoids exit the column, a detector measures their amount. UV detectors are commonly used because capsaicinoids absorb UV light. The detector’s data is analyzed to quantify the capsaicinoids, providing a chromatogram with peaks that correspond to different capsaicinoids.
  4. Calculation of SHUs: The concentrations obtained from the HPLC are converted into SHUs by multiplying the amount of capsaicinoids by a factor that relates the chemical concentration to sensory heat units. This factor is derived from the historical correlation between Scoville’s sensory method and the chemical concentrations.

Advantages of HPLC

Using HPLC for capsaicinoid analysis has several advantages:

  • Objectivity: It removes the subjectivity and variability of human testers.
  • Sensitivity: HPLC can detect capsaicinoids at very low concentrations.
  • Speed: The analysis is relatively quick, often completed within minutes.
  • Accuracy: HPLC provides precise measurements of each capsaicinoid compound.

Other Methods

While HPLC is the gold standard, other techniques, such as capillary electrophoresis and mass spectrometry, can also measure capsaicinoids. These methods offer their own advantages regarding sensitivity and specificity but may not be as widely used as HPLC.


The following are test requests Contract Laboratory has helped facilitate for chili peppers and other spicy foods:
  • Food analytical chemistry laboratory needed for Scoville heat units (SHU) rating testing for liquid Chilli hot sauce.
  • Australia Agriculture Laboratory needed for SHU tests of chili peppers
  • FDA GLP Food laboratory with approved test methods needed for enzyme testing of jalapeno peppers for enzyme activity of the following: Peroxidase Polygalacturonase
  • US Customs Broker needs private FDA Laboratory for salmonella testing on Korean chili peppers.
  • USA FDA and EPA Laboratory are needed for FDA and EPA pesticide testing. Analysis of pesticide residues on water and food samples as per FDA/EPA requirements. Food samples include bell and chili peppers. Sample amount: approx. 200 per month.
  • USA Food Analytical Chemistry Laboratory needed for testing chili peppers for Scoville heat units
  • USA (Puerto Rico) Food analytical chemistry lab needed for testing of peppers to adhere to FDA safety standards
  • Food Laboratory needed for chili oil testing: nutritional labeling and shelf life studies.
  • USA FDA-approved microbiology laboratory needed for sampling of imported Chili Power and Salmonella testing
  • Food laboratory needs for food artificial coloring testing for Ponceau 4R and FD&C yellow 6. Analysis by UPLC with PDA; in hot sauce and chili pepper.
  • Analytical chemistry laboratory needed for deformation of a spice mix (cayenne, chili, …).


 Are you a food laboratory interested in viewing more of our incoming food testing projects?  View food test requests


Are you a food manufacturer, distributor, importer, or restaurant that needs a laboratory to perform an analysis of capsaicinoid for Scoville Heating Unit (SHU) or other food testing, let Contract Laboratory save you time and money! Contact Us to see how we can help, or visit us online to submit your test request!

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