Plant-Based Oil-in-Water Food Emulsions: Exploring the Influence of Different Formulations on Their Physicochemical Properties

The global focus on incorporating natural ingredients into the diet for health improvement encompasses ω-3 polyunsaturated fatty acids (PUFAs) derived from plant sources, such as flaxseed oil. ω-3 PUFAs are susceptible to oxidation, but oil-in-water (O/W) emulsions can serve to protect PUFAs from this phenomenon. This study aimed to create O/W emulsions using flaxseed oil and either soy lecithin or Quillaja saponins, thickened with modified starch, while assessing their physical properties (oil droplet size, ζ-potential, and rheology) and physical stability. Emulsions with different oil concentrations (25% and 30% w/w) and oil-to-surfactant ratio (5:1 and 10:1) were fabricated using high-pressure homogenization (800 bar, five cycles). Moreover, emulsions were thickened with modified starch and their rheological properties were measured. The physical stability of all emulsions was assessed over a 7-day storage period using the TSI (Turbiscan Stability Index). Saponin-stabilized emulsions exhibited smaller droplet diameters (0.11-0.19 µm) compared to lecithin (0.40-1.30 µm), and an increase in surfactant concentration led to a reduction in droplet diameter. Both surfactants generated droplets with a high negative charge (-63 to -72 mV), but lecithin-stabilized emulsions showed greater negative charge, resulting in more intense electrostatic repulsion. Saponin-stabilized emulsions showed higher apparent viscosity (3.9-11.6 mPa·s) when compared to lecithin-stabilized ones (1.19-4.36 mPa·s). The addition of starch significantly increased the apparent viscosity of saponin-stabilized emulsions, rising from 11.6 mPa s to 2117 mPa s. Emulsions stabilized by saponin exhibited higher stability than those stabilized by lecithin. This study confirms that plant-based ingredients, particularly saponins and lecithin, effectively produce stable O/W emulsions with flaxseed oil, offering opportunities for creating natural ingredient-based food emulsions.

[HLA antigens in infants with bronchiolitis]

The frequency distribution of HLA antigen in 100 infants with bronchiolitis is compared to a control population of 100 healthy blood donors. No differences were found in the frequency distribution of both A and B antigens, but B 7 antigen was more frequently present in patients with bronchiolitis and increased serum IgE (47% VS 17% in the control group with normal serum IgE). Serum IgE was increased in 27% of the patients with bronchiolitis. The incidence of recurrent respiratory episodes was 62% in infants carrying the B 7 antigen whereas it was only of 14,5% in the whole series (pc less than 0,05). All infants with increased serum levels of IgE and recurrent respiratory episodes had the B 7 antigen. We believe that the presence of IgE and recurrent respiratory episodes had the B 7 antigen. We believe that the presence of B 7 antigen influence the clinical course of bronchiolitis in the sense that a high percent will present with recurrent respiratory episodes and increased levels of serum IgE.