While the foundations were shifting, there were people who continued working in and for the country, and that is the spirit of Venezuelans that makes us keep going, despite the adversities.
From the Dispersions and Interfaces Laboratory of the Physics Center of the Venezuelan Institute of Scientific Research (IVIC), a pioneering agri-food research project is being developed focused on the extraction of plant mucilage to offer sustainable biotechnological alternatives to synthetic and imported products using by-products of domestically produced tubers.
Native and ancestral species such as the Chinese taro (Colocasia esculenta), the yam (Dioscorea spp.) and the cassava (Manihot esculenta) are ceasing to be perceived solely as sources of carbohydrates for direct consumption to become true bio-refineries of high value-added hydrocolloids.
Biochemical Architecture: What is Mucilage?
From a molecular perspective, the mucilage of tubers is a complex, high-molecular-weight heteropolysaccharide. It is composed primarily of galactose and arabinose chains (branched polymers), galacturonic acid (units that carry a negative charge in aqueous environments), rhamnose, and xylose (in varying proportions depending on the genetic variety).
These macromolecules have a high water retention capacity due to the massive presence of hydroxyl groups forming three-dimensional cross-linked matrices capable of modifying the rheology (viscosity and fluidity) of aqueous solutions.
The project, led by Dr. Aly Castellanos Suárez, a specialist in Physical Chemistry, along with Chemical Engineering students from the Francisco de Miranda National Experimental University (UNEFM), is studying the kinetics of enzymatic browning in chemical reactions. The current focus is on the enzymatic browning of yams, a phenomenon where the tuber turns brown due to the action of at least three catalysts acting simultaneously.
“Each yam has a different enzyme load. In the lab, we're not trying to identify which enzymes are at work; we're simply evaluating how the browning changes over time. (…) When you evaluate both the yam pulp and the mucilage, you observe a color change over time. We take photographic records of these changes and subject both the pulp and the mucilage to different treatments, observing how the browning varies over time depending on each treatment. This process is very time-consuming in the lab, so we developed an Artificial Intelligence (AI) system. It's trained on images of untreated tubers, and after this initial training, the AI is fed photographs of different treatments to build a browning scale. This allows us to see how the browning changes over time, thanks to this tool developed in the lab,” Castellanos emphasized.
The innovation lies in the development of AI to identify color patterns in images; in addition, we are looking for potential byproducts, such as the formation of biodegradable films and extracts with protein properties, explains the doctor.
Foam Fractionation Methods
The biochemical challenge lies in effectively separating the polysaccharide matrix (mucilage and starch) from the protein components and residual phenolic compounds without degrading the molecular weight of the polymers.
This process occurs when the enzyme polyphenol oxidase (PPO) comes into contact with oxygen and phenolic compounds, progressively forming brown pigments called melanins. The goal is to apply pretreatments that prevent this enzymatic action without affecting product quality.
How do they do that?
First, they mechanically disintegrate the fresh tuber in an aqueous medium at low temperatures to avoid thermal or enzymatic degradation.
Fractional extraction: This is done using the foam method. The polysaccharides are absorbed onto the surface of the foam and then used in fractionation columns. The polysaccharides are absorbed onto the surface and then, when separated and broken down, this foam yields a more concentrated extract.
When the process is carried out in several stages, a higher degree of purity is achieved. These procedures avoid the massive use of solvents, which increases costs and environmental impact.
This foaming process is relatively new and is used to extract protein, a polysaccharide that is gaining a lot of momentum at the industrial level.
Ethanolic Precipitation:
The change in the dielectric constant of the medium dehydrates the polymer chains, causing the agglomeration and insolubilized precipitation of the pure mucilage through drying and spraying by circulating air also in a controlled manner, also called lyophilization, to obtain a light-colored powder, with rapid rehydration.
What is this powder used for?
It has applications in the pharmaceutical and food industries, specifically as biosurfactants. In food, it has been used to stabilize juices, ice cream, and baked goods; in pharmaceuticals, it is used to thicken formulas and cosmetic products.
Yams, as well as our tubers, due to their high concentration of starch and bioactive compounds such as diosgenin, represent not only a sovereign food source, but also a substantial value in the development of high-tech inputs, demonstrating that the answer to the industrial challenges of the present lies latent in the biodiversity of the soil with a Venezuelan seal.
