This CBD Coating Could Help Fruit Last Longer
Image credit: Allec Gomes via Unsplash
When it comes to strawberries, cream just got a new rival: CBD.
Researchers from Thammasat University and the Chulabhorn Research Institute, Thailand, have demonstrated that an edible coating containing nanoparticles of encapsulated CBD can help keep strawberries fresh for longer and delay the growth of mold.
Based on their findings, published in ACS Applied Materials & Interfaces, the researchers say that such CBD-containing edible coatings could be an “extremely beneficial” option for future fruit packaging and storage solutions.
The benefits of CBD
CBD is well-known for its calming properties and other therapeutic effects. But the cannabinoid has also shown some promising antioxidant and antimicrobial properties in previous studies. Of particular note are studies showing that CBD can inhibit the growth of Gram-positive and Gram-negative bacteria, as well as some species of fungi that can cause rot in fruits and vegetables and present a danger to human health, such as Aspergillus niger.
These properties would be very beneficial for improving fruit and vegetable storage, although for practical reasons it has not yet been possible to implement the use of these compounds. The oily nature of cannabinoids, such as CBD, makes them immiscible in water, which increases the difficulty of using them for food preservation.
In recent years, micro- and nanoencapsulation technology has become a popular method of improving the solubility of substances such as oils. This is also the case for CBD; studies have shown that nanoparticles of encapsulated CBD have improved solubility, stability, and bioavailability compared to regular CBD oil.
Encapsulated CBD nanoparticles can extend strawberry shelflife
In this new study, the researchers set out to discover whether encapsulated CBD nanoparticles could be added to known edible polymer coatings in order to create an improved food coating that might promote antimicrobial activity and extend the food freshness.
They first encapsulated pure CBD isolate in poly(D,L-lactide-co-glycolide), a biodegradable polymer commonly used in drug delivery. This process yielded nanoparticles of encapsulated CBD measuring just 400 nanometers in width.
To create the edible coating, the most stable nanoparticles were incorporated into a mixture of sodium alginate in water. Dipping strawberries into this mixture, followed immediately by a second dip into a mixture of ascorbic acid and calcium chloride, resulted in a colorless gel coating forming on the surface of the berries.
The CBD-coated strawberries, alongside an uncoated control and a control with only a basic non-CBD-infused sodium alginate coating, were then placed in open plastic containers and held at cool temperatures for 15 days. Visual color analysis, total acidity and pH tests, antioxidant activity assays, and microbiological analysis were done on each strawberry group at baseline and then every five days in order to compare the effects of the coatings to the untreated group.
The researchers found that the CBD-coated group ripened and decayed at a significantly slower rate than the control groups, with both the CBD-containing and CBD-free coated berries also retaining significantly more water weight due to their coatings.
The strawberries with the CBD nanoparticle coating also demonstrated the best performance in preserving the berries’ color and enhancing their natural antioxidant activity. Additionally, this coating exhibited the largest antimicrobial effects during storage, indicating its effectiveness at combatting mold and increasing the shelf life of the fruits.
CBD as an antibiotic
The antibiotic and antimicrobial action of CBD is something that has specifically received a lot of attention in recent years. In addition to warding off harmful molds, as demonstrated in this study, other trials have also found CBD to be effective against serious bacterial infections.
In a recent study, researchers at the University of Queensland found that synthetic CBD was able to kill the bacteria responsible for gonorrhea, meningitis, and legionnaires disease. In addition, a CBD formulation was also seen to be capable of breaking down the biofilms produced by Staphylococcus aureus. These biofilms are the slimy structural supports that assist the bacteria in surviving against other antibiotic treatments.
Speaking to Analytical Cannabis in 2019, shortly after the publication of another study investigating CBD’s antibiotic action, lead author Mark Blaskovich, an associate professor at the University of Queensland’s Institute for Molecular Bioscience, noted that researchers still do not fully understand the action of CBD or of many common antibiotics.
“We don’t know [its actions] yet, so that’s one thing that we’re very interested in investigating further,” Blaskovitch said.
“Even for antibiotics that have been around for a long time, like polymyxins which were discovered in the 1940s, we still don’t know, completely, their mechanisms of action,” he continued. “So if it’s effective at killing the bacteria, and it’s not inducing resistance – which appears to be the case for CBD – there shouldn’t be any significant roadblocks in advancing it further, from a regulatory perspective.”
With applications in improving food storage, preventing harmful mold, and combatting antibiotic-resistant bacteria, it is clear that CBD research is really only just beginning. But Blaskovitch also cautions consumers not to get carried away with any hype; the compound’s antibiotic properties have generally only been studied within specially prepared formulations.
“I certainly wouldn’t advise consumers to go out and be taking a lot of cannabidiol on their own to try treating infections – certainly for systemic infections; drinking or inhaling cannabidiol has not been shown to be effective at all,” he said.