The main challenge formulators face with colors exempt from certification is their stability: their ability to remain vibrant and consistent through processing and the product’s shelf life. Heat, light and even fat content can all impact stability, but it’s based on the color and the formulation’s pH. Any tip in a color’s pH, and the hue can change, either by a little or a lot.
“Our first question when working on a new project is ‘what is the pH?’ ” explained Emina Goodman, senior director, commercial color development, ADM, highlighting its importance. “Some botanicals naturally become very unstable when you shift the pH, so that is a key component.”
And this is where the exempt colors come into play. Not all colors behave the same, making certain raw material sources or color hues better suited to certain applications.
“A lot of colors in the pink to purple range come from anthocyanins, which are pH sensitive and can change color based on pH,” explained Alice Lee, applications manager, GNT. “In the bakery and snack space, applications can have a higher pH than other food categories. With a yeasted bread or tortilla, the pH might be 4.5, giving you a bright pink or purple, while a higher pH would create a more blue-ish purple.”
This is why understanding the pH sensitivity of the color is so important as well as the pH of the formulations. For example, chemical leavening agents can increase the pH of a dough when they are present, and that impact on color can be dramatic.
“Chemical leavening agents use an acid-base reaction during baking, which creates carbon dioxide gas to aerate and lighten doughs and batters,” said AnnMarie Kraszewski, application scientist, Oterra. “As a result, they increase the pH of the dough and may cause anthocyanins from fruit and vegetable juices to shift shade from red to blue.”
Heat can also have a detrimental effect on a color, which is an issue for bakery and snack products that may endure high temperatures in an oven, fryer or extruder. But again, some colors handle heat just fine, and bakers can push the limits when creating the most statement-making bakery items.
“Some color hues are really optimal for high-heat bakery applications like yellow, brown, oranges and pinks,” Ms. Lee said. “But sometimes people want really saturated color like rainbow bagels or intense black or red.”
Bakers have a few options when working with more heat-sensitive colors or when they are trying to get extremely saturated color. They can switch to a color that has been bred at the source to be more heat resistant.
Oterra, for example, developed its Hansen sweet potato to be less sensitive to heat and pH changes, providing formulators with an alternative to beet-sourced colors, which typically are sensitive to changes.
Bakers can also adjust their processing by baking for longer at lower temperature.
“Bakers using our anthocyanin-rich Suntava Purple Corn Extract Powder, Flour or Meal have found that slight adjustments to the cook time and temperature can help them achieve their desired color,” said Terry Howell, Suntava Purple Corn ingredient expert for Healthy Food Ingredients.
When working with a high-saturation product and the process can’t be changed, formulators can use a higher dosage of color. That will require, however, formulation changes as adding more color is never just adding more color when it comes to botanically sourced ingredients.
This article is an excerpt from the July 2021 issue of Baking & Snack. To read the entire feature on Colors, click here.