How to measure the colour of tomato products

How to measure the colour of tomato products

Measuring the colour of tomato products

Tomato products, regardless of how they are prepared, should always maintain the familiar base colour of red. If the topic is ketchup, purée, pasta sauces or soup, red is generally the main identifying colour of the tomato ingredient.

If we take the manufacturing processes of most tomato based products, there are a variety of different stages where measuring colour would be beneficial, each starting with the tomato itself; why put through tomatoes of debatable appearance when they could affect the final product?

There are a few stages in which tomato products can be assessed for colour quality and measurements can be taken at either one or all of these stages, depending on how thorough operatives are or how much time can be spared. An ideal solution would be for there to be a machine that could measure the tomato product at any stage of the process, regardless of its state. Having a truly versatile machine would complement the quality control process at any phase.

If we look at the production process for ketchup, the first step actually involves whole, fresh tomatoes and is a good place to start the quality control process. There is little point in attempting to keep a good, consistent colour of ketchup throughout batches if substandard tomatoes are used to begin with. The following steps in the process could be measured as needed and at the most appropriate moment, depending on individual manufacturer procedure.

After cooking is an optimal time for measurements as the colour after this stage could indicate an error with heating, such as the batch being over or under cooked, resulting in a darker or lighter appearance than the norm,.

Additional ingredients can also have an effect on the overall final appearance of ketchup. These ingredients can either be assessed for colour quality before adding to the mix or the effect they have on the tomatoes after adding.

Right at the end of production is the last opportunity for measurements and the last quality check before shipping. A measurement at this point is essential to negate any discrepancies during manufacturing that may have produced a substandard product.

Is it complicated to include colour measurement in quality control processes?

It doesn’t have to be. The introduction of appearance analysis should be done primarily to the manufacturers own needs and can be as thorough or as basic as required. With an instrument, such as the ColorFlex EZ Tomato Spectrophotometer, the tomato at any point of the manufacturing process, be it the fresh tomato or tomato paste, can be measured. The ColorFlex EZ Tomato is equipped with the Lycopene index (the phytochemical found in tomatoes) as well as the Hunter L, a, b and the CIE L*, a*, b* colour scales, meaning it is brilliant as taking measurements of not only tomato products, but also any other ingredient that may require analysis.

That is what can make the process extremely simple and beneficial to any company. The only main concern for operatives would be with regards to sample preparation. With vast amounts of tomato products being made, it is imperative to have a procedure in place that ensures all operatives prepare, measure and record sample data in a concurrent way. Having removed the variables of human error, it can then be positively assumed that any erroneous results received are caused by the samples and therefore the batch being produced at that moment.

A straightforward method should include how to load a sample for measurement. What is going to hold the sample? A recommended container would be a circular glass sample cup that is designed for use with the ColorFlex EZ Tomato and deep enough to hold a good amount of the sample. However, in a busy environment, these glass cups may break if care is not taken. As an alternative, a plastic sample cup can be used that does not break as easily but are subject to scratching more; these scratches can affect colour measurements.

Another variable would be how much sample to use. If we are speaking in terms of a paste-like sample, an amount of sample should be used so that the sample isn’t see through but, on the other hand, shouldn’t be full to the brim as this would cause spillages that, if cleaned, would take up valuable operator time and, if negated, could cause inaccurate results (particularly if spillages are made on the instrument itself).

With an instrument that can accommodate set-ups for each stage of production, a rough method can include half filling a sample cup, loading it onto a machine, selecting the relevant set-up and reading the sample. After reading the sample, the cup should then be emptied and cleaned thoroughly to prevent any contamination between samples.

Despite appearing complicated and time consuming, including colour measurement as part of the quality control process can be easy and extremely worthwhile. When combining an extremely versatile colour measurement spectrophotometer with a perfected procedure for appearance analysis, there is no such thing as poor customer satisfaction.

Content Written by Rachael Stothard

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How to measure the colour of tomato products

HunterLab Colourflex EZ Spectrophotometer

Like all members of the ColorFlex EZ family of products, the ColorFlex EZ Tomato is specifically built to meet and exceed your colour measurement needs. Every ColorFlex EZ Tomato comes with 60 years of colour quality control experience and innovation by HunterLab, the world’s true measure of colour.

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