Avocados, the latest green berry craze containing over 20 vitamins and minerals in their flesh, have been found to contain vibrant orange food colorant capabilities within the compounds of their seeds.
Nearly two decades ago, Gregory Ziegler, Penn State professor of food science, said he coincidentally came across the phenomenon that a ground-up avocado seed produces a bright orange color.
Ziegler said he kept this in mind years later as the food industry saw a push for the use of natural food colorants versus synthetic ones.
“The market for food coloring is mostly for prepared foods,” Zeigler said. “A lot of those dyes are synthetically manufactured.”
Synthetic dyes are commonly used because they are stable, have a long shelf-life and produce vivid colors. The alternative, natural colorants, are typically less stable, degrade after a shorter time period, and are more expensive and less vibrant.
Joshua Lambert, associate professor of food science and co-director of the Center for Plant and Mushroom Foods for Health, explained that the public demand for natural colorants has significantly increased over the years, pressuring companies to remove synthetic dyes from their food.
“There have been some studies out there on the relationship between synthetic colors and things like attention deficit and hyperactivity disorder,” Lambert said, “[stating] that certain synthetic colors might contribute to development of hyperactivity and attention disorders.”
Lambert said the data for these studies is not very good, however, the possibility is off-putting to consumers when they read a food label for a product containing synthetic ingredients.
In light of this, Ziegler and Lambert began further research of the avocado seed.
Together, they co-advised Deepti Dabas, a doctoral degree student in food science, with her thesis research project, Colored Avocado Seed Extract.
While the project began with research on the seed’s coloring capabilities, Zeigler said Dabas became interested in the biological effects of the avocado seed extract oil and pursued further analysis of its antioxidant, anti-inflammatory and anti-cancer properties.
Lambert said they noticed the avocado seed contained polyphenol, an anti-inflammatory compound found in foods like dark chocolate.
Given the nature of their lab, studying the “prevention of chronic diseases like metabolic syndrome and cancer and inflammatory bowel disease by dietary components,” Lambert said they already had tests set up to look at anti-inflammatory and anti-cancer activity in the avocado seed.
They found that the seed did contain anti-inflammatory properties. However, Zeigler said the samples Dabas tested were very crude, or unrefined, extracts of the oil and because of this,
the specific compound responsible for the anti-inflammatory properties is unknown.
However, the originally material was isolated with methanoyl, so it is known that the anti-inflammatory compound is within that mix.
Finding vegetarian and vegan options is not that easy while being a student at Penn State.
In the future, Ziegler said he is interested to see if the color compound in the avocado seed is the same compound responsible for the seed’s anti-inflammatory properties.
To test this, Zeigler said they would use cell cultures to introduce an inflammatory compound and measure the cellular response through expression of different signaling molecules.
The same process would be repeated with their avocado seed compound to determine if it suppressed the inflammatory response.
“The next step is to look at a model, probably an animal model, looking at some inflammatory disease,” Lambert said.
Currently, there articles on the internet contain information, recommendations and recipes for the consumption of an avocado seed due to its alleged medicinal benefits, many of which reference Ziegler and Lambert’s research with the seed extract.
The recipes range from smoothies made with blended avocado seeds to avocado seed tea.
“You have to use a little bit of caution because really there’s no body of scientific evidence that says that it’s totally safe,” Zeigler said. “But there’s nothing that says it isn’t safe.”
Zeigler added that historically, the avocado seed has been used by indigenous people for its gastrointestinal benefits.
Due to a potential conflict of interest, Ziegler said he and Lambert have plans to continue their research regarding the medicinal components of the avocado seed with the university and potentially Hershey Medical Center and their research regarding the coloring component off-campus.
In 2016, Ziegler and Lambert co-founded Persea Naturals alongside Emmanuel Hatzakis to continue their research of the avocado seed as a colorant for commercial use, AvoColor.
Hatzakis, assistant professor at the Ohio State University, joined forces with Ziegler and Lambert roughly five years ago. His specialty in NMR spectroscopy allowed him to help with structural determination and compositional analysis of the avocado seed.
“We think that this is going to be a unique niche for this color,” Ziegler said. “[AvoColor] is very vivid, much more stable than natural colors and it’s produced from avocado seeds.”
Hatzakis added that AvoColor is stable against heating, oxygen and light — three important components of commercial production and uncommon for natural colorants.
Another similarity among natural food colorants is their production from edible fruits and vegetables. For example, the color red typically comes from beets or pomegranates.
“Avocado seeds are different because they’re a waste product,” Zeigler said. “We’re not diverting food from the food stream to make a colorant.”
Ziegler said their goal with Persea Naturals is to upcycle the seeds in order to produce edible, valuable products out of them.
Another problem with natural food colorants is that they maintain the flavor of the product they were extracted from. Ziegler mentioned two common natural colorants; red cabbage and turmeric, as being difficult to isolate the color from the flavor.
AvoColor, does not have an avocado taste. Instead, through testing, Zeigler said they found it produced a slight tea aroma which they are working on removing.
AvoColor is not currently available for public consumption. Ziegler and Lambert said they are testing the product safety before submitting a proposal to the FDA for approval of commercialization and production.