Liquid Fruit Color Measurement

With vivid colors, intricate shapes, diverse and appealing flavors, Fruits are nature's sweets. Is it any wonder that humans have been eating fruit in some form since the beginning of time? The world's leading producers of fruit and fruit products understand the importance of color in a consumer's perception of ripeness and flavor. That's why for over 60 years, companies like Smuckers, PepsiCo, Kraft, ConAgra Foods and Chiquita have relied on the experience and knowledge of HunterLab in providing color measurement solutions for their products.

Fruits that are processed into a liquid such as fruit juice may require a different measurement approach, depending on the opaqueness of the liquid. Highly opaque fruit liquids should be measured using a reflectance instrument, while translucent or transparent fruit liquids should be measured using a transmittance instrument. For more on measuring liquids, please refer to the following PDF: HunterLab Solutions Chart.

Opaque Liquids are impenetrable by light and are best measured using a reflectance spectrophotometer that uses 45/0° geometry. This is the geometry that most closely matches how the human eye sees color.

Translucent Liquids allow light to pass through, but only diffusely, so that objects on the other side cannot be clearly distinguished. Either reflective and transmittance measurement modes may work well, depending on the translucency of the sample.  As a rule of thumb,

• - If at the path length that your customer will view the sample, you can see slight details of your thumb or finger through the liquid, then transmittance is the preferred measurement method.

• - If you cannot see slight details, then reflectance measurement using directional 45°/0° is preferred, though it is also possible to use diffuse d/8° sphere geometry.

Path length is defined as the thickness of the sample from where the light enters to where it exits the sample. A simple test to determine the translucency is to pour the liquid into a clear container that simulates the thickness that the sample will normally be viewed, and hold your thumb on the back of the container and look through the sample.

Transparent Liquids allow light to pass through with little or no interruption or distortion so that objects on the other side can be clearly seen. These liquids can only be measured using transmission instrumentation.