In this study, membrane-based methods were evaluated for the recovery of FucoPol, the fucose-rich exopolysaccharide (EPS) secreted by the bacterium Enterobacter A47, aiming at reducing the total water consumption and extraction time, while keeping a high product recovery, thus making the downstream procedure more sustainable and cost-effective. The optimized method involved ultrafiltration of the cell-free supernatant using a 30 kDa molecular weight cut-off (MWCO) membrane that allowed for a 37% reduction of the total water consumption and a 55% reduction of the extraction time, compared to the previously used method (diafiltration-ultrafiltration with a 100 kDa MWCO membrane). This change in the downstream procedure improved the product’s recovery (around 10% increase) and its purity, evidenced by the lower protein (8.2 wt%) and inorganic salts (4.0 wt%) contents of the samples (compared to 9.3 and 8.6 wt%, respectively, for the previously used method), without impacting FucoPol’s sugar and acyl groups composition, molecular mass distribution or thermal degradation profile. The biopolymer’s emulsion-forming and stabilizing capacity was also not affected (emulsification activity (EA) with olive oil, at a 2:3 ratio, of 98 ± 0% for all samples), while the rheological properties were improved (the zero-shear viscosity increased from 8.89 ± 0.62 Pa·s to 17.40 ± 0.04 Pa·s), which can be assigned to the higher purity degree of the extracted samples. These findings demonstrate a significant improvement in the downstream procedure raising FucoPol’s recovery, while reducing water consumption and operation time, key criteria in terms of process economic and environmental sustainability. Moreover, those changes improved the biopolymer’s rheological properties, known to significantly impact FucoPol’s utilization in cosmetic, pharmaceutical or food products.

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Biobased raw materials like natural polysaccharides are increasingly sought by the cosmetic industry for their valuable properties. Such biodegradable and usually non-cytotoxic biopolymers are commonly used in skin-care products as rheological modifiers, bioemulsifiers and/or bioactive ingredients. FucoPol is a natural polysaccharide with reported biocompatibility, emulsion-forming and stabilizing capacity, shear-thinning behavior and bioactivity (e.g., antioxidant capacity, wound healing ability) that potentiate its utilization in skin-care products. In this study, olive oil and α-tocopherol containing emulsions were stabilized with FucoPol. Although the presence of α-tocopherol negatively impacted the emulsions’ stability, it increased their emulsification index (EI). Moreover, FucoPol outperformed the commercial emulsifier Sepigel® 305, under the tested conditions, with higher EI and higher stability under storage for 30 days. The formulation of FucoPol-based emulsions with olive oil and α-tocopherol was studied by Response Surface Methodology (RSM) that allowed the definition of the ingredients’ content to attain high emulsification. The RSM model established that α-tocopherol concentration had no significant impact on the EI within the tested ranges, with optimal emulsification for FucoPol concentration in the range 0.7–1.2 wt.% and olive oil contents of 20–30 wt.%. Formulations with 25 wt.% olive oil and either 0.5 or 2.0 wt.% α-tocopherol were emulsified with 1.0 wt.% or 0.7 wt.% FucoPol, respectively, resulting in oil-in-water (O/W) emulsions. The emulsions had similar shear-thinning behavior, but the formulation with higher FucoPol content displayed higher apparent viscosity, higher consistency, as well as higher firmness, adhesiveness and cohesiveness, but lower spreadability. These findings show FucoPol’s high performance as an emulsifier for olive oil/α-tocopherol, which are supported by an effective impact on the physicochemical and structural characteristics of the emulsions. Hence, this natural polysaccharide is a potential alternative to other emulsifiers.

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Driven by the customers’ growing awareness of environmental issues, the production of topical formulations based on sustainable ingredients is receiving widespread attention from researchers and the industry. Although numerous sustainable ingredients (natural, organic, or green chemistry-derived compounds) have been investigated, there is a lack of comparative studies between conventional ingredients and sustainable alternatives. In this study, olive oil (30 wt.%) and α-tocopherol (2.5 wt.%) containing oil-in-water (O/W) emulsions stabilized with the bacterial fucose-rich polysaccharide FucoPol were formulated envisaging their validation as cosmetic creams. After formula composition design by Response Surface Methodology (RSM), the optimized FucoPol-based emulsion was prepared with 1.5 wt.% FucoPol, 1.5 wt.% cetyl alcohol, and 3.0 wt.% glycerin. The resulting emulsions had an apparent viscosity of 8.72 Pa.s (measured at a shear rate 2.3 s−1) and droplet size and zeta potential values of 6.12 µm and −97.9 mV, respectively, which are within the values reported for cosmetic emulsified formulations. The optimized formulation displayed the desired criterium of a thin emulsion system, possessing the physicochemical properties and the stability comparable to those of commercially available products used in cosmeceutical applications.

FucoPol is an acylated polysaccharide with demonstrated valuable functional properties that include a shear thinning fluid behaviour, a film-forming capacity, and an emulsion forming and stabilizing capacity. In this study, the different conditions (concentration, temperature, and time) for alkaline treatment were investigated to deacylate FucoPol. Complete deacetylation and desuccinylation was achieved with 0.02 M NaOH, at 60 °C for 15 min, with no significant impact on the biopolymer’s sugar composition, pyruvate content, and molecular mass distribution. FucoPol depyruvylation by acid hydrolysis was attempted, but it resulted in a very low polymer recovery. The effect of the ionic strength, pH, and temperature on the deacetylated/desuccinylated polysaccharide, d-FucoPol, was evaluated, as well as its emulsion and film-forming capacity. d-FucoPol aqueous solutions maintained the shear thinning behaviour characteristic of FucoPol, but the apparent viscosity decreased significantly. Moreover, contrary to FucoPol, whose solutions were not affected by the media’s ionic strength, the d-FucoPol solutions had a significantly higher apparent viscosity for a higher ionic strength. On the other hand, the d-FucoPol solutions were not affected by the pH in the range of 3.6–11.5, while FucoPol had a decreased viscosity for acidic pH values and for a pH above 10.5. Although d-FucoPol displayed an emulsification activity for olive oil similar to that of FucoPol (98 ± 0%) for an oil-to-water ratio of 2:3, the emulsions were less viscous. The d-FucoPol films were flexible, with a higher Young′s modulus (798 ± 152 MPa), a stress at the break (22.5 ± 2.5 MPa), and an elongation at the break (9.3 ± 0.7%) than FucoPol (458 ± 32 MPa, 15.5 ± 0.3 MPa and 8.1 ± 1.0%, respectively). Given these findings, d-FucoPol arises as a promising novel biopolymer, with distinctive properties that may render it useful for utilization as a suspending or emulsifier agent, and as a barrier in coatings and packaging films.

The main function of vitamin C, as an antioxidant, is to combat free radicals and prevent premature aging, smoothing wrinkles and expression lines. In addition, it acts directly on depigmentation and prevention of blemishes on the skin. In this study, natural oils (30 wt.%) and α-tocopherol (2.5 wt.%) containing oil-in-water (O/W) emulsions stabilized with the bacterial fucose-rich polysaccharide FucoPol were formulated, adding L-ascorbic acid as an antioxidant. The optimized formulations were obtained with 8.0 wt.% L-ascorbic acid for the Olea europaea oil formulation (C1) with a ƞ value of 2.71 Pa.s (measured at shear rate of 2.3 s−1) and E24 = 96% and with 15 wt.% L-ascorbic acid for the Prunus amygdalus dulcis formulation (C2) with a ƞ value of 5.15 Pa.s (at a shear rate of 2.3 s−1) and E24 = 99%. The stability of the FucoPol-based formulations was investigated over 45 days at 4 °C, 20 °C, and 30 °C. The results showed that all formulations maintained the organoleptic characteristics, with pH variations (5.7–6.8 for C1, and 5.5–6.03 for C2) within the regulations for cosmetic products (4 ≤ pH ≤ 7). The accelerated stability tests proved the formulations’ stability at 4 °C with EI = 95% for C1 and EI = 100% for C2. The rheological assessment demonstrated that the formulation presents a shear-thinning and liquid-like behavior. Regarding textural parameters, formulations C1 and C2 displayed an increase in firmness and consistency with similar spreadability during the shelf life. These findings further demonstrate FucoPol’s functional properties, acting as an emulsifier and stabilizer polysaccharide in cosmetic formulations containing L-ascorbic acid.

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