In part one of this series, it was explained that a bright-colored egg yolk always comes from a healthy hen. It was also explained that the pigmentation depends on several factors but that a key one is the source and feed stability of the carotenoids used for the process. Carotenoids are by nature susceptible to degradation by light, heat and oxidative agents. Storage, milling, premixing, feed processing and feed storage consequently present multiple opportunities to reduce the number of active particles per gram of final product. Technology has therefore been developed to protect them throughout the entire feed manufacturing process.
DSM uses a beadlet technology containing canthaxanthin in a cornstarch-coated matrix of lignosulfonate. Butylated hydroxytoluene (BHT) is added as an antioxidant. The aim is to have the best-performing and most stable red carotenoid in the animal nutrition market. In order to verify the process, DSM’s Nutrition Innovation Center in Kaiseraugst, Switzerland, carried out an experiment involving the most important brands of red carotenoids. Samples were received from different markets, analyzed for initial content verification, and stored at 4 °C until they were ready to be tested. They were then subjected to three different processes in order to evaluate their stability across the whole feed production cycle.
1. Stability as is:
Samples were stored at 30 °C with 65% relative humidity (rH) in polyethylene (PE) pouches, and the canthaxanthin content was measured after 0, 1, 3 and 6 months.
2. Stability in premix:
Samples were incorporated in a vitamin/mineral premix containing 3.8 % of choline chloride and 2.5% of trace minerals. After incorporation, the samples were stored at 25°C with 60% rH, and the canthaxanthin content was evaluated after 1, 3 and 6 months of storage.
3. Stability in feed:
Feed containing 64% wheat and 28% soybean meal was prepared at the feed mill of the Nutrition Research Center in Village-Neuf, France. After mixing, it was processed at 90 °C and stored in polyethylene (PE) bags at an ambient temperature (20–25 °C, with 30–60% rH). To define stability, the canthaxanthin content was measured in feed samples after 0, 1 and 3 months.
After the three processes were completed, a calculation of total stability was performed, taking Carophyll® red 10% as the standard. The analysis was performed in duplicate at DSM’s analytical Research Center in Kaiseraugst, Switzerland.
Stability As Is
The initial content and participant products are presented in Table 1. Nine different samples from seven different makers were analyzed. Samples from DSM, NHU and ZMC were above the declaration level, while Juyuan was inside the calculated analytical error margin. The rest of the products were below the expected level at the beginning of the trial. Differences in initial content can be attributed to time after production, packaging, formulation, storage conditions, and coating technology. Several of the products show a satisfactory initial content of canthaxanthin, which is one of the main characteristics that feed companies look for worldwide. However, an initial low content related to the declaration may be the result of one or several factors that are not in accordance with the customer’s expectations. Graph 1 shows the results of the recovery trial for the product As Is.
Differences between individual products in the degradation rate of canthaxanthin are a direct consequence of different formulation technologies – packaging, storage conditions and timing being equal. After one month of storage at 30 °C with 65% rH, Carophyll® red and the ZMC products were above 90% of the initial value, while Avixanthin® was at 85%. The product from Leader® was clearly behind the rest at 40%. However, after 6 months of storage, Carophyll® retained 88% of the initial value, while all the rest were below 66% and the Leader product was at 18%. This is of particular consequence in view of the fact that products are shipped globally and can spend several months in transportation or stored in sub-optimal conditions. The formulation of Carophyll® has been designed to provide the maximum possible protection to the active molecule, especially during transportation and storage.