USP creates technology that protects food during digestion – 06/13/2023 – Health

Bioactive compounds, mainly present in fruits and vegetables, exert different biological actions in the body associated with health promotion and increased well-being. They are attributed antioxidant, anti-diabetic, anti-aging and anti-cancer effects, among others.

Scientists have been studying ways to optimize the absorption of these compounds in the digestive tract, increasing their bioavailability. One of these ways is to nanoencapsulate the substances so that they are released slowly, resisting the digestive process and the action of the bacteria of the intestinal microbiota.

This is what two scientists from the Department of Food Science and Experimental Nutrition at the Faculty of Pharmaceutical Sciences at the University of São Paulo (FCF-USP) have been doing in various works, the most recent being published in the International Journal of Biological Macromolecules. Both are members of the Food Research Center (FoRC), a Fapesp Research, Innovation and Dissemination Center (CEPID).

“We use pectin extracted from residues of the albedo [a parte branca] and the rind of citrus fruits, with a degree of purity that allows food consumption. They were prepared using methods that exclude any chemical component harmful to human health”, says João Paulo Fabi, co-author of the work and professor at FCF-USP.

In the review article, the scientists describe the use of pectins as a material for encapsulating bioactive compounds. In addition, they present a new technology developed by the group. “We form a pectin nanocomplex with lysozyme, a safe substance for food consumption extracted from egg whites, which gives the product more stability. And, thus, we form a protective network for a very sensitive bioactive compound: anthocyanin”, he summarizes.

Anthocyanins are water-soluble pigments belonging to the group of flavonoids, phenolic compounds present in vegetables and responsible for a wide variety of colors observed in flowers, fruits, leaves, stems and roots of plants, whose color can vary from carmine red to violet/blue .

The methodology suggested by the duo can be used to encapsulate other water-soluble bioactive compounds. “We tested with anthocyanin because it is a very challenging compound and sensitive to many factors, such as, for example, light, temperature, pH and intestinal bacteria”, informs Thiécla Katiane Osvaldt Rosales, first author of the article.

The work also received funding through two other projects (19/11816-8 and 12/23970-2).

Benefits

According to the researchers, the main advantage of the developed method is that, in addition to pectin, lysozyme and encapsulated material (anthocyanin), there is no substance added. “We use three compounds from natural sources and mix them in the laboratory to form a new product, without adding salts, binders, or anything that could be potentially toxic. Furthermore, nanoparticles are not that small. When they are very small, they go beyond the barriers and cell membranes and enter the DNA, potentially having a toxic effect. The size we got is safe”, summarizes Fabi.

Rosales briefly explains the process for obtaining nanoparticles. “Pectin and lysozyme are heated separately, as the increase in temperature causes a partial change in the structure, allowing the substances to interact better. we mix it with the material that will be encapsulated when pectin and lysozyme reach a temperature that will not be harmful to anthocyanin, a very sensitive and unstable compound. We mix the three in aqueous suspension and, after an hour of stirring, what results is already the nanoencapsulated anthocyanin. Then, the suspension goes through a filtration process so that the non-encapsulated content is separated.”

According to her, special care is taken with factors such as temperature and pH. “We tested the optimization of the parameters, mainly the pH. It cannot be high, because it degrades the anthocyanin, and not too low. The final pH was 5, considered optimal for the interaction between the molecules. The time and intensity of agitation were also tested. We try to pay attention to all the small details, but that make the difference for the formation of stable particles. We have already deposited the patent for the methodology.”

Results

In the end, the effectiveness of the encapsulation was tested in vitro, in a simulated digestion system that mimics the gastric and intestinal phases.

“The result is that a part of the anthocyanin was released during the digestive process, already at the end of the gastric phase, and a part was trapped in the nanostructure, with the possibility of releasing the rest in the intestinal environment or else being fully absorbed as part of the nanostructure. We believe it’s a good result”, celebrates Rosales.

The next step will be testing on animals. “We tested in vitro and found results that indicate that the nanoparticles are safe for consumption. We have evidence that the cells can absorb them in a non-toxic way and that the pectins protect the anthocyanins and their properties. Now, we have to test them in animals. Observing the process from oral ingestion to find out how the anthocyanins are absorbed, using specific absorption markers, to understand the path they take in the organism and their biological destination”, he says.

The main idea of ​​the scientists is to use nanoparticles as a food supplement. “They can be added to food and dietary supplements. But it would be necessary to scale industrially to include them in a supplement”, ponders Fabi.

In this regard, it is worth noting that the strategy does not require expensive equipment or procedures. “Furthermore, the material used for the nanocapsules, which comes from by-products of the peel of citrus fruits, would make the cost even lower for the industry. This pectin that we use in the work is a product that exists commercially, used by the food industry, generally to form gel in jellies, or used as a thickener”, complements Rosales.