Testing for cannabis potency can be a difficult task, given the lack of standardization in testing parameters and procedures.
New research, published in the “Journal of Agricultural and Food Chemistry,” suggests a product’s matrix can also impact a lab’s ability to precisely test for cannabinoid content. This especially applies to chocolate, thanks to its complex balance of fats, sugars and cocoa compounds.
Author David D. Dawson, research scientist at Vertosa, recently spoke to Cannabis Products about the “matrix effect” and the importance of having strong relationships and communication with testing facilities.
CP: Why did you decide to research the interaction between chocolate and cannabinoids?
DD: In the world of cannabis potency testing, the goal is to extract all of your molecules of interest (known as “analytes,” in this case cannabinoids) from the product in question (known as the “matrix,” in this case chocolate). Some matrices are very easy to extract cannabinoids from, such as traditional flower — it's very thin, has high surface area, and is porous. Thus, organic solvent can easily attract the cannabinoids out of the flower matrix and into solution, so we can measure them and calculate the potency of the flower sample.
As the cannabis industry has expanded, there are more and more complicated new product types, which can frustrate our ability to test. That's why we focused on chocolate to start — it's a very common product type, but the chocolate matrix is highly complex and difficult to analyze. Chocolate contains cocoa fats, milk fats, sugars, and naturally occuring flavor compounds, all of which can interact with cannabinoids, trapping them in the matrix and making it difficult to determine the potency.
CP: What was your hypothesis going into the research?
DD: This research project was based on an almost anecdotal abnormality we noticed when testing chocolate products. It appeared that the potency of infused chocolates varied depending on how much we tested, which doesn't exactly make sense. One gram of chocolate should have the same concentration of cannabinoids as 2 grams. So what could explain that?
We proposed that there was some sort of “matrix effect” occurring between the chocolate matrix and our cannabinoid analytes. “Matrix effect” is a term used to describe when the matrix itself interferes with analytical testing procedures, and it seemed to be consistent with that anecdotal variance we noticed.
CP: How would you describe what you found?
DD: In short, we found that the chocolate matrix does indeed affect our ability to accurately and precisely measure the cannabinoid content of infused chocolate products. The more chocolate that was present when testing, the lower the amount of cannabinoids we recovered. This suggests that as we increase the amount of chocolate compared to cannabinoids, there is more matrix present to interfere with our analytical testing, thus increasing the matrix effects.
This proposed matrix effect seems to be tied to multiple components in the chocolate matrix itself, including but not limited to fats and polyphenols. The more surprising discovery for me was found when we compared how different cannabinoids reacted to the chocolate matrix. We found that not all cannabinoids are equally affected by the chocolate matrix, and the degree of matrix interference could be tied to several structural features on the cannabinoid molecules.
CP: What does this mean for manufacturers of cannabinoid-infused chocolate?
DD: Fortunately for cannabis-infused chocolate producers, this isn't an issue with their product: it's an issue on the analytical testing side. My findings do not affect the potency of the chocolate (i.e. the amount of cannabinoids present), it only affects our ability to accurately and precisely measure it in the lab. My advice to cannabis chocolatiers concerned about these findings is to communicate to their testing lab partners and make sure they are aware of this phenomenon and are testing in a manner that minimizes/eliminates the issue.
CP: What would you suggest product developers of cannabinoid-infused chocolate do to get around the issues with interference?
DD: Again, this matrix interference phenomenon is going to be a given in any cannabis-infused chocolate: cannabinoids are lipophilic by nature, meaning they are attracted to fats (think of cooking cannabis flower in butter to make edibles: the cannabinoids love the fat!). Even non-fat chocolate products would have some degree of interference, as it seems the naturally occuring flavor compounds in cocoa can cause matrix effects as well.
Product developers should have a good working relationship with a testing lab and make sure that the lab is testing in a way to minimize or eliminate this phenomenon. This is an issue for testing labs, and not producers or consumers.
CP: What could this research mean for incorporating other cannabinoids besides D9-THC, CBD, CBG and CBN?
DD: One of the major takeaways of this research is that each individual cannabinoid has different chemistries and thus can be easier or harder to analyze, depending on the matrix. In the future, when cannabis testing is far more established and testing methods begin to become standardized, one could envision testing protocols are not only given for each matrix type (e.g. chocolate, gummy, beverage) but also each cannabinoid (e.g. THCV, CBDA, THC). Each cannabinoid is a different and distinct molecule, it's not surprising that they would behave differently.
CP: What could this research mean for other confectionery applications?
DD: The findings of this research — that fat and naturally occuring flavor compounds can interfere with analytical measurements — are not just limited to infused chocolates. Countless products on the market are high in fat (e.g. cookies, brownies, topicals) and thus there could be an analogous phenomenon occurring in those products. Many products contain naturally occurring flavor compounds outside of the scope of what was tested here and could interfere with cannabinoids in a presently unknown way. The long and short is: until we test each cannabinoid against each matrix type, we will never be sure that we're testing products in the most precise and accurate way possible, as there always could be another undocumented matrix effect that confounds us.
CP: Do you intend to explore interference between cannabinoids and other food/beverage matrices?
DD: A broad and rigorous investigation of food/beverage interference on cannabinoids is a necessary next step for the cannabis industry, as only when we have a detailed knowledge of the products, the cannabinoids, and the interactions between them will we be able to establish standardized testing methods for the cannabis industry.
In my current role as research scientist at Vertosa, a cannabinoid infusion company, I am actively looking at cannabinoid compatibilities and stabilities in a rapidly growing and highly complicated product class: cannabis-infused beverages. It takes a lot of effort and patience to unlock the chemical nuance of infused products, but it will allow us to create a new generation of cannabis products that are stable, precisely dosed, safe and delicious!
CP: Is there anything else you’d like to add?
DD: The cannabis industry needs more scientists and more scientific inquiry. All of these investigations and experiments big and small will eventually be done, and we need to find these answers in order for the industry to push forward into legalization. The Scientific Method is making its way into the cannabis industry, one test at a time!