It can be jarring to crack an egg and see a bright orange yolk instead of the expected pale yellow, or vice versa. Americans eat on average nearly 300 eggs a year, making it likely you’ll stare down an unusual (for you) shade of yolk at some point.
While poultry researchers note that an orange yolk isn’t necessarily better than a yellow one, the shade can indicate how the hen might have been raised. We tapped four poultry experts to explain what’s behind the spectrum of egg yolk shades, and what each one means.
What colors can egg yolks be?
There are a lot of possibilities when it comes to egg yolk color. “Egg yolk color can range anywhere from almost white to a blood-red color,” says Richard Blatchford, PhD, a poultry researcher and associate specialist in Cooperative Extension: Small to Industry Scale Poultry at the UC Davis Department of Animal Science. “But the extremes are pretty rare to see.”
Grocery store eggs usually have a bright yellow or pale orange yolk, but there are variations within these colors, he says.
Poultry experts and farmers even keep track of yolk color. The DSM Yolk Color Fan is a 16-scale color index that distinguishes yolk color and is widely used in the poultry industry. Under the scale, each number corresponds with a different shade. Number one, for example, is a pale yellow, while 16 is a deep shade of orange. “People really tend to like the rich, dark-colored yolks,” says Blatchford.
What influences the color of an egg yolk?
There are a lot of factors that can influence the egg yolk color a hen produces, and most of it comes down to diet, says Sunoh Che, DVM, PhD, assistant professor of poultry management at University of Maryland. These are the biggest factors, according to experts:
The composition of the hen’s feed: The amount of yellow-orange carotenoids [plant pigments], like lutein from alfalfa meal and zeaxanthin from marigold flower extract, “significantly affects yolk color,” says Che.
The amount of corn in the feed: Corn can influence how yellow a yolk is, says Blatchford. “Hens that make grocery store eggs are usually fed a corn-based diet,” he says. “That’s why most of our grocery store eggs are a yellow color, but not really bright.”
Xanthophyll content: Xanthophyll is a yellow compound that influences egg yolk color, says Hillary Ayers, family and consumer sciences agent with University of Florida, Institute of Food and Agricultural Sciences Extension Orange County. “Xanthophyll is found throughout the world, but is commonly found in leaves and grain,” she says. “Not all plant material is equal when it comes to containing xanthophyll — some have higher concentrations and different types.” The type of xanthophyll-containing plants a chicken eats can influence the color of the yolks, she says.
Access to a fresh pasture: “Hens with access to fresh grass and pasture tend to produce eggs with more vibrant yolk colors,” says Che. That’s because these hens generally have a more varied diet with sources of protein from bugs and carotenoids and xanthophyll from plants.
Source :https://www.msn.com