Measuring food color equals quality

Susanne Hauder, HunterLab

Measuring the colour of food is more and more important in the food and beverage product industry. As consistent colour means high standard quality, colour measurement is able to confirm company’s slogans of best offers.

“Colour is an important attribute for food and we frequently judge food quality based on colour.”
-Christian Jansen, European Manager Sales HunterLab

Today the range of food and beverage for the end-consumer is tremendous. Companies compete for the best products to offer. And the single consumer is selective as never before. Values like freshness and unchanging flavor convinces customers and boosts sales. HunterLab machines support food makers in manufacturing for values like safety, genuineness and quality. A range of portable, bench, and on-line systems for the most different measuring types is offered by HunterLab and the unique service support attends to every HunterLab customer.

However food processors are often limited in their ability to adjust colour in the final food product. Because of this, they pay strict attention to the colour of ingredients and to the changes that occur during each step of production. Colour measurement instruments can be used to check ingredient colour and to evaluate the efficiency of processes in obtaining or maintaining the desired product colour

The food industry provides an almost infinite variety of product shapes, textures and optical characteristics. For this reason, methods and instruments for colour measurement are selected based on the optical characteristics of the food product.

• Opaque Food - These are seen wholly by reflected light and include such foods as; fruit, crackers, corn flakes, cheese puffs, flour, tomato juice, cheese and meat.
• Translucent Food - These are seen partially by reflected and partially by transmitted light. Many fruit juices, jams, and custards fall into this category.
• Transparent Food - Clear juices, wines, jellies, gelatins, vegetable oil and soft drinks are some examples of foods in this category.

The best system to measure opaque liquids, pastes, powders and small granules is a 45º/0º geometry instrument with a horizontal sample port like the HunterLab ColorFlex or LabScan XE. The sample is simply poured into a sample cup and placed over the instrument port for measurement. For flat slab samples such as blocks of cheese or slices of meat the sample is placed directly on the sample port of the ColorFlex or LabScan XE. A sample port aperture with glass insert is recommended to prevent juices from dripping into the instrument.

When measuring coarse granules, flakes, chips, and disks (i.e. cookies and crackers), the best system is a 45º/0º geometry instrument with circumferential illumination and a large measurement port such as the HunterLab D25L-9000 Tristimulus Colorimeter. This geometry compensates for the directional effect of the sample, and the large measurement area provides a good optical average of the non-uniform sample. The system is network and PC compatible and its built-in printer provides a hard copy of results.

Translucent samples require special handling when being evaluated. The colour of a translucent sample will change when the light path length through it is changed. Thus the path length must be fixed. HunterLab has developed a "Ring and Disk" assembly to measure this type of sample. A cup with ring, disk and sample are placed on the instrument port for measurement. The LabScan XE or ColorFlex are the instruments of choice for this type of application.

Transparent food is measured by transmission instead of reflection. Products such as clear juice, soft drink, vegetable oil, and brewed tea are poured into a transmission cell. The cell with sample is then placed in the transmission compartment of an instrument having sphere geometry (such as HunterLab UltraScan PRO and ColorQuest XE). Both the UltraScan PRO and ColorQuest XE have the ability to measure transmission haze as well as color. This haze value is frequently related to turbidity for products such as clear juices and brewed tea.

The primary reason why many food companies use HunterLab instrumentation is attributed to the unique optical designs and sample handling techniques the company has developed for the variety of food products. From oils and translucent liquids, to coarse or fine ingredients, sauces, pastes, and textured or non-uniform products, HunterLab offers portable, bench-top and in-line system

About HunterLab:

HunterLab is the world leader in the colour measurement of food products. A wide range of portable, laboratory and on-line colour measurement systems are available to meet specific application requirements. Their corporate philosophy is focused on total customer satisfaction. HunterLab is a global company that provides worldwide support through local representation in more than 65 countries.

For more information, please call HunterLab at (703) 471-6870, send e-mail to info@hunterlab.com or visit www.hunterlab.com.