The Ratio Does the Work: What a Tucuma Oil Bigel Study Reveals About Formulating Two Gels as One

A bigel sounds like a trick: blend a water gel and an oil gel together at the right temperature and get a semisolid that supposedly delivers the hydration of one phase and the emollience of the other without the compromises of a standard emulsion. A design-of-experiments (DoE) study published in the November/December 2025 issue of Cosmetics & Toiletries, in its Sensory ingredients section, tests that premise with a concrete pairing: hydroxyethylcellulose (HEC) gelling the aqueous phase, and tucuma oil, from the Amazonian palm Astrocaryum vulgare, structuring the oil phase. The study sits behind a registration wall, so the byline and full protocol were not independently confirmed, but the public framing, "Optimizing Bigels for Sensoriality and Efficacy," points to findings about how the two phases interact mechanically rather than about either ingredient in isolation.

That framing matters because a bigel is not one formula decision but several stacked on top of each other. Someone has to pick a hydrophilic polymer to gel the water phase (HEC here, though xanthan, guar, alginate and carrageenan all show up in the literature), a structurant for the oil phase (tucuma oil standing in for the candelilla wax or beeswax that dominates published bigel recipes), and then a ratio at which the two preformed gels get blended under high shear. Change any one input and the others have to answer for it: a stiffer aqueous gel needs a different blending temperature to avoid shearing the oil structure apart, and a softer oil phase shifts where the internal/external phase boundary sits. A 2020 rheological review in Food Hydrocolloids on bigels and multi-component organogels already established that this internal-versus-external phase question is the main variable governing spreadability and stability, which is the backdrop the C&T DoE work is building on rather than discovering fresh.

Tucuma oil gives the formulation a sourcing story that cosmetics marketers already know how to tell. Natura sells it in Brazil under the Ekos Tukuma line, body oils and balms sourced through women-led cooperatives in the Amazon, with a regeneration narrative tied to post-fire land recovery. The oil itself is rich in lauric and oleic acids in butter form, and in some sourcing it carries palmitic acid and beta-carotene, which is what underpins its billing as an emollient with antioxidant activity. None of that chemistry is new to cosmetic science. The oil has been commercially available and INCI-listed for years. What the C&T study is actually testing is whether tucuma oil behaves predictably when it is no longer the finished product's main emollient but one structural phase in a two-gel system, where its fatty acid profile has to interact with a wax or structurant to set a stable organogel in the first place.

This is where the formulation-systems lesson gets sharper than the ingredient story. A March 2025 review in the Journal of Dispersion Science and Technology, covering bigel applications across pharmaceuticals, food and cosmetics, describes patent activity in cosmetic bigels as still "emerging," meaning thin rather than mature. Most of the prior published recipes pair a polysaccharide hydrogel with candelilla wax: a 2022 study on date palm cellulose nanocrystal-reinforced guar gum paired with sesame oil and candelilla wax, and more recent work on carob extract bigels, both point to the same conclusion, that the hydrogel-to-oleogel ratio is the dominant lever for texture, well before anyone swaps in a specialty oil. If that holds here too, the real contribution of the HEC/tucuma DoE work is less about discovering a new emollient effect and more about mapping how far a formulator can push the ratio before a specific oil phase, with its own melting behavior and fatty acid mix, breaks the system's stability.

That distinction, between a new raw material and a new way of assembling known ones, is also a regulatory one. Tucuma oil needs no new approval; it is already on the market. HEC needs none either. What a DoE study of this kind actually produces, if it holds up once the full methodology is available, is a map of processing windows, which shear rate, which blending temperature, which phase ratio, keeps a specific oil-polymer pairing from separating or losing its sensory profile on the shelf. That map is worth more to a formulator planning a production run than any single claim about tucuma oil's antioxidant content, because it is the part of the system that decides whether the jar on a store shelf still looks like the one blended in the lab six months later.