RESUMO
Herein, three types of ovalbumin (OA)-polysaccharide conjugates were prepared with three polysaccharides (XG: xanthan gum; GG: guar gum; KGM: konjac glucomannan) for the fish oil emulsion stabilization. The glycation did not change the spectra bands and secondary structure percentages of OA, whereas it decreased the molecular surface hydrophobicity of OA. The initial emulsion droplet sizes were dependent on the polysaccharide types, OA preparation concentrations, polysaccharide: OA mass ratios, and glycation pH. The emulsion stability was mainly dependent on the polysaccharide types, polysaccharide: OA mass ratios, and glycation pH. However, it was minorly dependent on the OA preparation concentrations. The emulsions stabilized by conjugates with high polysaccharide: OA mass ratios (e.g., ≥3:5 for OA-GG) or appropriate glycation pH (e.g., 5.0-6.1 for OA-XG) showed no obvious creaming during the room temperature storage. This work provided basic knowledge on the structural modification and functional application of a protein.
RESUMO
Herein, the effects of anionic xanthan gum (XG), neutral guar gum (GG), and neutral konjac glucomannan (KGM) on the dissolution, physicochemical properties, and emulsion stabilization ability of soy protein isolate (SPI)-polysaccharide conjugates were studied. The SPI-polysaccharide conjugates had better water dissolution than the insoluble SPI. Compared with SPI, SPI-polysaccharide conjugates had lower ß-sheet (39.6 %-56.4 % vs. 47.3 %) and α-helix (13.0 %-13.2 % vs. 22.6 %) percentages, and higher ß-turn (23.8 %-26.5 % vs. 11.0 %) percentages. The creaming stability of SPI-polysaccharide conjugate-stabilized fish oil-loaded emulsions mainly depended on polysaccharide type: SPI-XG (Creaming index: 0) > SPI-GG (Creaming index: 8.1 %-21.2 %) > SPI-KGM (18.1 %-40.4 %). In addition, it also depended on the SPI preparation concentrations, glycation times, and glycation pH. The modification by anionic XG induced no obvious emulsion creaming even after 14-day storage, which suggested that anionic polysaccharide might be the best polysaccharide to modify SPI for emulsion stabilization. This work provided useful information to modify insoluble proteins by polysaccharides for potential application.
Assuntos
Emulsões , Óleos de Peixe , Galactanos , Mananas , Gomas Vegetais , Polissacarídeos Bacterianos , Solubilidade , Proteínas de Soja , Mananas/química , Polissacarídeos Bacterianos/química , Gomas Vegetais/química , Emulsões/química , Proteínas de Soja/química , Galactanos/química , Óleos de Peixe/química , Ânions/químicaRESUMO
Three types of tilapia scale gelatins (hot water-pretreated gelatin, HWG; acetic acid-pretreated gelatin, AAG; and pepsin enzyme-pretreated gelatin, PEG) were extracted and their gel strength, foaming properties, and emulsifying properties were analyzed. They had different gel strength values: AAG (370 ± 10 g Bloom) > HWG (320 ± 10 g Bloom) > PEG (280 ± 10 g Bloom). The creaming index values of tilapia scale gelatin-stabilized fish oil-loaded emulsions were dependent on gelatin type (HWG ≈ AAG > PEG) at low gelatin concentration (2 mg/mL), whereas they were similar and low (8-10 %) at high gelatin concentration (10 mg/mL). Extraction methods had no consistently significant effects on the gelatin foaming properties. In summary, tilapia scale gelatins had better gel strength and foaming properties and similar or even better emulsifying properties than mammalian gelatins. Therefore, tilapia scales could be a potential source of gelatins to replace mammalian gelatins.