How Colour Signifies Freshness in Canned Tomato Paste

The desired red colour of canned tomato paste comes from a mature tomato fruit with a sweet flavor and high concentration of lycopene. The United States Department of Agriculture (USDA) uses the tomato paste score (TPS) to grade the product and ensure it meets quality and consumer expectations.

Colour and appearance matter because they are the first purchasing factors customers consider. When customers cook with tomato paste, they have certain expectations tomato paste manufacturers must meet to indicate the product's freshness.

What Colour Should Tomato Paste Be? 

Consumers expect tomato paste from fresh tomatoes to be red or deep red. When the USDA first established tomato paste colour classifications, ratings relied on visual assessments.

The USDA has three colour classifications for tomato paste:

1. Grade A: The tomato paste is a “good colour” of a bright red and scores 45 to 50 points.
2. Grade C: The tomato paste has a “fairly good colour,” generally red with a dull or brown cast, and scores 40 to 44 points.
3. Substandard: The tomato paste fails to meet Grade C standards and scores 0 to 39 points.

What Causes Colour Changes in Tomato Paste?

Various factors may lead to browning or other colour changes, including:

• Oxidation: Tomato paste may be exposed to the air during canning due to improper sealing, which leads to discoloration.
• High temperatures: Tomato paste may lose pigments due to excessive heat during canning or storage.
• pH levels: Tomato paste may turn yellow as it ages if the acidity is too high.
• Light exposure: Tomato paste may lose colour over time due to UV light exposure.

What Solutions Work for Measuring Tomato Paste Colour?

Spectrophotometers are the trusted colour measurement solutions for ensuring tomato paste colour falls within prescribed tolerances. These devices determine the tomato paste's colour measurement results based on a specific formula. These parameters are used to calculate the TPS. The United States Department of Agriculture's (USDA) Processed Products Standards and Quality Certification allocates more than one-fourth of the tomato paste quality grade to this colour index reading.

A spectrophotometer can also support the determination of lycopene concentration using a Lycopene Index measurement, as high concentrations of lycopene create the sweet flavor and vibrant red colour consumers want from their tomato products.

How to Measure Tomato Paste Colour With a Spectrophotometer

Here's a general overview of the process of measuring tomato paste colour with a spectrophotometer:

1. Calibrate: Verify the solution will provide accurate measurements by calibrating it according to the manufacturer's instructions.
2. Select: Navigate the menu to find the desired colour measurement scale.
3. Prepare: Create a representative sample by distributing tomato paste into a sample cup and covering it.
4. Run: Measure the sample with the spectrophotometer and record the results.
5. Compare: Determine whether the sauce falls within the accepted tolerances you have set around the target standard

Improve Tomato Product Quality and Consistency With HunterLab

HunterLab is a pioneer in tomato paste colour measurements, with over 70 years of expertise in the field. Our spectrophotometers were the equipment of choice for the USDA when the agency created the first colour-scoring system for tomato product quality in the late 1970s.

Today, we continue to innovate with the debut of ColorFlex L2. This model is our most powerful spectrophotometric solution for tomato-based goods to date, specially engineered for colour measurement in every form, from fresh tomatoes to pastes, juices, soups, and sauces. ColorFlex L2 is ready to integrate right out of the box with smart, user-friendly features and the industry's most comprehensive library of tomato colour scales.

Learn more about how ColorFlex L2 can boost your efficiency and support better quality control by contacting our experts online for details.