dsm-firmenich egg yolk pigmentation guidelines

A golden yolk can only come from a healthy hen

In order for a yolk to present an attractive golden color, carotenoids have to:

  • Be ingested in sufficient quantities
  • Absorbed (via a healthy gut)
  • Not be used as antioxidants (low immunological challenges)
  • Not be used as vitamin precursor (good vitamin status).

Therefore the hen, the environment and the feed have to work in concord to deliver an attractively pigmented yolk. In nature, the male birds with the best coloration will attract the females. This makes sense, because only the healthier individuals will be able to obtain appealing feathers. The same goes for the females: the healthier hens will have more carotenoids for their eggs. So, in order to have a golden yolk, you need a good-quality feed, the correct husbandry practices and - more importantly - a healthy hen.

Factors affecting egg yolk pigmenting efficiency

The egg yolk pigmenting efficiency of carotenoids is determined by two main factors: egg yolk deposition rate and carotenoid color (wavelength).

Deposition in egg yolk

Deposition of dietary carotenoids in the egg yolk depends on the individual carotenoid molecule (Figure 1). As the content of carotenoids in the feed increases, their concentration in the egg yolk rises in direct proportion.

Figure 1. Egg yolk deposition rates of various carotenoids

The color of carotenoids

The wavelengths of the colors of the carotenoids used for egg yolk pigmentation fall between 400 nm and 600 nm within the visible range of the color spectrum.
To the human eye, such compounds are yellow to red in color. Lutein, zeaxanthin and apo-ester are yellow carotenoids (wavelength from 445 to 450 nm), whereas canthaxanthin is a red carotenoid (wavelength from 465 to 470 nm).

Figure 2. Wavelengths of various carotenoids used for yolk pigmentation.

The principle of egg yolk pigmentation

There are two components of egg yolk pigmentation. The first (referred to as the saturation phase) involves the deposition of yellow carotenoids to create a yellow base corresponding to a dsm-firmenich YolkFan™ score around 7. Such a yellow base is very important for good saturation of the final color. Once the yellow base is established, the addition of the red carotenoid canthaxanthin (CAROPHYLL® red) changes the hue to a more orange-red color (the second component, or color phase). The dose-related color response to red carotenoids is higher than the response to yellow carotenoids, and the combination of yellow and red carotenoids is therefore more cost-effective for egg yolk pigmentation. Figure 3 illustrates this principle.

Figure 3. Egg yolk pigmentation phases

Regarding the relative pigmenting efficiencies of the yellow carotenoids, apo-ester (CAROPHYLL® yellow) is more efficient than lutein and zeaxanthin, the main carotenoids in feedstuffs. The very high deposition rate of apo-ester (CAROPHYLL® yellow) makes it the most suitable yellow carotenoid for the saturation phase. Table 1 below shows the relative pigmenting efficiency of yellow carotenoids (based on deposition rates).

Table 1. Relative pigmenting efficiency of yellow carotenoids

How to use the dsm-firmenich YolkFan™

The dsm-firmenich YolkFan™ provides a simple means of measuring yolk color. However, attention should be paid to the following factors during the procedure:

  1. The evaluation should be carried out against a white non-reflective surface, in order to eliminate the influence of adjacent colors.
  2. Use indirect daylight with no strong artificial light. It is important to avoid reflection from the glossy surface of the yolk.
  3. The blades of the fan should be held immediately above the yolk, viewed vertically from above, with the blade numbers facing down and the yolk between the tips of the blade. The reader should always face the side of the blade with no numbers and show the number to the assistant for recording. Between each egg, the fan should be closed to ensure the independency of every measurement.
  4. The evaluation of any experimental series should be carried out by the same trained observer. The series should comprise between four and 15 eggs (depending on variability), and they should be evaluated individually.
  5. When finished, please clean the fan and keep it away from direct sources of light.

How to obtain the required dsm-firmenich YolkFan™ score with CAROPHYLL®

First set the dsm-firmenich YolkFan™ score. If you choose 12/13, most of your eggs will fall between these two scores.

Refer to table 3 and calculate the amount of xanthophyll contained in the ingredients used in the formulation; and to finish, review table 4 to know how much CAROPHYLL® yellow and red is needed to obtain the required dsm-firmenich YolkFan™ score.

Example: the target dsm-firmenich YolkFan™ score is 13. The feed contains 15% yellow corn, 2% corn gluten (60%) and 1% DDGS. Table 3 shows that the yellow xantophyll content of this feed is 6 ppm.

At this point, you can use least cost formulation or use table 5 to fix the required levels of CAROPHYLL® yellow and CAROPHYLL® red.

Table 3. Example for calculating the xanthophyll content of feed


An example of a possible least cost formulation:

To obtain a dsm-firmenich  YolkFan™ score of 13, you need 10.5 ppm of yellow carotenoids (yellow base). Following the example from Table 3, we have to add 4.5 ppm of yellow carotenoids on top of the feed content (10.5-6). When using Apo-ester, we divide this amount by 3 (Table 1), reflecting its higher pigmenting efficacy. Therefore, we have to add 1.5 ppm of Apo-ester (15 ppm of CAROPHYLL® yellow 10%) and 4 ppm of Canthaxanthin (40 ppm of CAROPHYLL® red 10%).

Table 4. Total carotenoids needed for least cost formulation

Recommended levels

Table 5. Recommended levels 1,2 of CAROPHYLL® yellow and CAROPHYLL® red for yolk pigmentation according to the target dsm-firmenich YolkFan™ score

Development of the new dsm-firmenich YolkFan™ with 16 blades

During the last few years, the global egg industry (especially in Asia) has been experiencing an accelerated development, leading to a proliferation of brands and market offers. The idea of a golden yolk always coming from a healthy hen is being adopted widely, and as a consequence, we have consumers asking for a deeper shade of color in their eggs. For this very reason, dsm-firmenich customers asked us a few years back for the new and higher blade numbers for the dsm-firmenich YolkFan™.  Our scientists in France and Switzerland set about constructing the requisite blade and developing the accompanying recommendations, with the support of our Marketing team in Asia-Pacific. Trials were carried out, yolks were evaluated via chemical and optical analysis, and the appropriate samples were sent to the ink developing supplier. The ink and the blade have to reflect the selected yolk hue and present a consistent appearance under different lighting conditions (like the rest of the dsm-firmenich YolkFan™ blades). Blades 1 to 15 are exactly the same shades as before, so you can still use the same standards. After two years of work and the recreation of the entire dsm-firmenich YolkFan™ range, we are very proud to present the new 16-blade dsm-firmenich Yolk Fan™.

dsm-firmenich YolkFan™

CAROPHYLL® products - consistent egg yolk color

Many years of experience in carotenoid chemistry have given dsm-firmenich the expertise to manufacture CAROPHYLL® products of exceptional quality.

CAROPHYLL® yellow 10% and CAROPHYLL® red 10% are free-flowing, granulated carotenoid products. They consist of small beadlets in which the carotenoid is finely distributed in a starch-encapsulated plant and carbohydrate matrix to which antioxidants have been added, making CAROPHYLL® products animal-free.

The special manufacturing process, known as ‘spray-dried coating’, protects the carotenoids against oxidation and gives them high stability, water dispersability, outstanding mixing properties, and very good absorption characteristics.

CAROPHYLL® beadlets
Table 2. Specifications of CAROPHYLL® yellow 10% and CAROPHYLL® red 10%

Published on

05 September 2018


  • Carotenoids
  • Layer
  • Poultry


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