Physical Stability of Oil-In-Water Emulsion Stabilized by Gelatin from Saithe (Pollachius virens) Skin

A novel method for encapsulating nutritional supplements within edible films

Many nutritional supplements are hydrophobic solids or oils that are extremely difficult to administer in tablet form. These supplements are often consumed as large soft gels that may represent a choking hazard. In addition, many nutritional supplements produce an aversive taste or tactile response when consumed orally. Because of these limitations, improved delivery methods for administering nutritional supplements to the oral cavity represent an important goal. In this study, vitamin E acetate is exploited as a model nutritional supplement for developing an improved oral delivery method by encapsulating this vitamin within rapidly dissolving edible films. Vitamin E acetate was solidified by mixing this oil with a long-chain fatty alcohol. The resulting wax was then pulverized and added to an aqueous polymer solution that included melted gelatin. The mixture was then sonicated to form a stable emulsion that was dried to a thin, flexible film. Vitamin E acetate was successfully encapsulated within films at amounts that approximated the minimum daily requirement for this supplement. Minimal loss of this vitamin occurred when the emulsion was dried to a film. Average film thickness was 150 µm, and the encapsulated vitamin E was not degraded. Film formulations that included the excipients sucralose and peppermint oil produced taste intensity ratings in the moderate range, and displayed favorable hedonic responses. In summary, rapidly dissolving edible films have been developed that greatly increase the load capacity of a hydrophobic oral supplement. These edible films represent a promising approach for delivering hydrophobic oils or solids to the oral cavity at bioavailable amounts.

Development and Characterization of Pickering Emulsion Stabilized by Walnut Protein Isolate Nanoparticles

This study was conducted to prepare walnut protein isolate nanoparticles (nano-WalPI) by pH-cycling, combined with the ultrasound method, to investigate the impact of various nano-WalPI concentrations (0.5~2.5%) and oil volume fractions (20~70%) on the stability of Pickering emulsion, and to improve the comprehensive utilization of walnut residue. The nano-WalPI was uniform in size (average size of 108 nm) with good emulsification properties (emulsifying activity index and stability index of 32.79 m²/g and 1423.94 min, respectively), and it could form a stable O/W-type Pickering emulsion. When the nano-WalPI concentration was 2.0% and the oil volume fraction was 60%, the best stability of Pickering emulsions was achieved with an average size of 3.33 μm, and an elastic weak gel network structure with good thermal stability and storage stability was formed. In addition, the emulsion creaming index value of the Pickering emulsion was 4.67% after 15 days of storage. This study provides unique ideas and a practical framework for the development and application of stabilizers for food-grade Pickering emulsions.

Gelatin from Saithe (Pollachius virens) Skin: Biochemical Characterization and Oxidative Stability in O/W Emulsions

This study performed the extraction of gelatin from saithe (Pollachius virens) skin and compared it to commercial marine gelatin. As a first stage, we investigated the physicochemical and biochemical properties of the gelatin. SDS-PAGE analysis revealed the presence of α-chains, β-chains, and other high-molecular-weight aggregates. DSC thermograms showed typical gelatin behavior, while the FTIR spectra were mainly situated in the amide band region (amide A, amide B, amide I, amide II, and amide III). In the second stage, we produced O/W emulsions and analyzed their physical and oxidative stability over 9 days. Oil droplets stabilized with the gelatins obtained from saithe fish skin had a size of ~500 nm and a ζ-potential ~+25 mV, which is comparable to oil droplets stabilized with commercial gelatin products. Moreover, the oxidative stability of the emulsions stabilized with gelatin from saithe fish skin showed promising results in terms of preventing the formation of some volatile compounds towards the end of the storage period compared to when using the commercial gelatins. This study indicates the potential application of fish skin gelatin in the fields of food and cosmetics, as well as suggesting that further investigations of their techno-functional properties.