Rheological and water binding properties of xanthan, guar and ultra-finely milled oatmeal in white birch sap: Influence of sap minor constituents

Exploring the potential of white birch sap: A natural alternative to traditional skin whitening agents with reduced side effects

Common tyrosinase (TYR) inhibitors used in cosmetics, such as hydroquinone, kojic acid, and arbutin, can cause side effects including erythema, skin peeling, and dryness. Therefore, the development of natural whitening agents that offer excellent permeability, minimal irritation, and high safety has become a primary focus in the field of TYR inhibitors. In this study, we demonstrate that White birch sap (WBS), within a safe concentration range, effectively reduces TYR activity and melanin content in both B16F10 mouse melanoma cells and zebrafish larvae. Importantly, WBS exhibits minimal irritation to neutrophils in fluorescent zebrafish and does not affect the behavior of adult zebrafish. Furthermore, WBS downregulates the gene expression levels of microphthalmia-associated transcription factor, TYR, tyrosinase-related protein-1, and tyrosinase-related protein-2 in B16F10 cells. In conclusion, our research confirms that WBS, a naturally derived substance, offers high safety and mild effects, making it a promising candidate for a skin-whitening agent.

Effect of Birch Sap as Solvent and Source of Bioactive Compounds in Casein and Gelatine Films

Birch sap consists of a natural water-based solution with valuable compounds such as minerals, sugars, organic acids and phenolic compounds that can be used advantageously in the preparation of edible films. In this study, gelatine- and casein-based films were prepared using birch sap as biopolymer solvent and source of bioactive compounds with the aim of developing new bioactive materials for food packaging. The physical, mechanical, barrier, antioxidant and iron-chelating properties of the obtained films were investigated. Birch sap enhanced the mechanical properties of the films by increasing puncture strength and flexibility, as well as their ultraviolet-visible light barrier properties. In addition, the presence of bioactive compounds endowed the birch sap films with an antioxidant capacity of almost 90% and an iron-chelating capacity of 40-50% with respect to the control films. Finally, to test these films as food packaging material, a photosensitive curcumin solution was packed and exposed to ultraviolet light. Tested films were able to protect curcumin against photodegradation, and the presence of bioactive compounds inside the birch-sap-enriched materials offered an additional 10% photoprotective effect compared to control films. Results showed the potential of birch sap as an environmentally friendly biopolymer solvent and plasticizer that can improve the mechanical and photoprotective properties of the prepared materials.

Viscosity development from oat bran β-glucans through in vitro digestion is lowered in the presence of phenolic compounds

Dietary fibres have been shown to aggregate and lose viscosity and water binding capacity in solution in the presence of phenolic compounds. This study aimed to verify this observation in a complex grain system containing β-glucans. The viscosity of uncooked and cooked oat bran digested in vitro was measured in the presence of 1-30 mM phenolic acids or flavonoids, and digestograms were modelled to understand the effects of phenolic compounds on the drivers of viscosity. The final viscosity of the digesta, driven by β-glucans, underwent a significant decrease of up to 31% upon the addition of phenolic compounds. To account for the inhibitory activity of phenolic compounds on digestive enzymes, modelling of the digestograms was adjusted with reference to that from previous work. The models suggest that phenolic compounds can simultaneously: (1) slow down the release of β-glucans by slowing down digestion through enzyme inhibition, and (2) decrease the viscosity of solubilised β-glucans, likely through colloidal aggregation as observed in solution before. These in vitro results suggest that the health benefits of oats linked to digestive viscosity of β-glucans may be altered by co-formulation with or co-ingestion of phenolic compounds.

Influence of polysaccharide concentration on polyphenol-polysaccharide interactions

Non-covalent interactions between polysaccharides and phenolics affect the physical properties of polysaccharide solutions. These interactions may in turn be influenced by polysaccharide-polysaccharide interactions. To test this hypothesis, we studied the influence of polysaccharide concentration (with guar, β-glucans, and xanthan) on the variations of rheological and water-binding properties upon addition of phenolics compounds (vanillin, caffeic acid, gallic acid, and epigallocatechin gallate). Addition of phenolics led to increased flow behavior index and decreased flow consistency index, with maximum effects at polysaccharide concentrations ranging between 0.6 × C* and 1.4 × C*, where C* is the critical overlap concentration of each polysaccharide. Water mobility was generally not significantly influenced by the addition of phenolics. The results showed that the ability of phenolic compounds to induce aggregation of polysaccharides in solution was strongly influenced by polysaccharide concentration around C* and therefore by polysaccharide-polysaccharide interactions.