How Spectrophotometers Measure Caramel Colour Additives: Using the Hue Index for Analysis

Caramel coloring is a commonly added food colorant to many foods, especially in baked goods where a homemade appearance is desirable.
Image Source: Flickr user Rebecca Siegal

For years I have been buying wheat bread as a healthier alternative to white bread, but recently I learned that the rich brown colour that I’ve come to associate with whole grains may simply be a caramel colour additive that is used to manipulate consumer perception. Well, it works! My own personal preference has not changed, despite the knowledge that two products may only vary in colour. My visual perception directly affects my taste and I still lean towards the rich brown colour that my brain has grown accustomed to.

Manufacturers are also aware of the important role that colour plays in consumer choice. Colour additives serve a very important purpose in today’s food industry, and food and beverage companies must find ways to appeal to both the oral palette as well as a visual one. Caramel colour is highly effective in altering the colour composition of many foods, and spectrophotometers offer the ability to accurately measure colour changes as caramel colour is added. In doing so, manufacturers can achieve the desired appearance that consumers demand, and with consistent results each time.

The advantages of caramel colour additives

Many processed food companies rely on caramel colour to enhance their product appeal because of its affordability, manufacturing ease, and availability. Due to its mild flavor and a bland aroma, caramel colour does not significantly impact the taste or smell of the finished product. It is used in a variety of products such as soft drinks, baked goods, seasonings, pet foods, soups, coffee products, syrups, and more.

In addition to the high desirability of caramel colour, it is also preferred as a more natural alternative than other food colour additives and does not carry the same regulations that are associated with artificial colour choices. The FDA (Food and Drug Administration) identifies caramel coloring on its list of colour additives exempt from certification, as long as the additive adheres to the specific criteria as stated:

1. The colour additive caramel is the dark-brown liquid or solid material resulting from the carefully controlled heat treatment of the following food-grade carbohydrates.
2. The food-grade acids, alkalis, and salts listed in this subparagraph may be employed to assist caramelization, in amounts consistent with good manufacturing practice.
3. Polyglycerol esters of fatty acids, identified in 172.854 of this chapter, may be used as antifoaming agents in amounts not greater than that required to produce the intended effect.
4. Colour additive mixtures for food use made with caramel may contain only diluents that are suitable and that are listed in this subpart as safe in colour additive mixtures for coloring foods.
   

As long as this criteria is met, caramel colour can be used safely and effectively to enhance the visual appeal of food products. However, it is necessary to monitor these steps carefully to ensure proper use of additives and effective measurement of colour during the heating processes.

Caramel colour as a food additive is highly effective, affordable, and exempt from the strict certification guidelines of the FDA, making it an ideal choice for food enhancement.
Image Source: Flickr user LadyDragonflyCC – >;<

Colour Measurement and the Hue Index

Caramel coloring is often measured using a ratio of absorbance values through spectral analysis. These measurements are then used for evaluation using a method called the Hue Index, which usually ranges from 3.4 (very dark walnut brown) to 7.5 (amber red brown) for caramel colours (0.1% solution). This method has various uses, and is heavily relied upon for the measurement of tea products and beer brewing colour variations as well.

Caramel colour additives are used by various industries and are measured using the Hue Index, which quantifies the colour hue or red characteristics of the caramel colour.
Image Source: Flickr user James Lee

Manufacturers in the food industry are looking for a caramel colour supply that exhibits colour strength and compatibility with other ingredients. Several factors influence colour measurement and consistency, as well as compatibility according to the desired application. Factors such as pH, positively and negatively charged ions, and product consistency (wet or dry product batches) all influence product needs and compatibility, and require advance spectrophotometers for accurate measurements. Time also influences caramel coloring, as it tends to darken with age, making constant monitoring and analysis a necessity.

Colour Measurement Instrumentation

For the measurement of the variations in caramel colour products, spectrophotometric instrumentation needs to be designed to manage various sample batches, wet or dry product samples, and a variety of viscosities. HunterLab offers an assortment of instrumentation options designed for each individual market need to accommodate a variety of sample batch sizes and consistencies. Our experienced staff is here to help you choose the right instrumentation designed to meet your specific budget and application requirements. Contact HunterLab today to learn more about how colour measurement can create uniformity and stability in your colour additive products and applications.