Effect of oil phase properties on peptide release from water-in-oil-in-water emulsions in gastrointestinal conditions
Citation
Giroux, H.J., Shea, R., Sabik, H., Fustier, P., Robitaille, G., Britten, M. (2019). Effect of oil phase properties on peptide release from water-in-oil-in-water emulsions in gastrointestinal conditions. Food Science and Technology - LWT, [online] 109 429-435. http://dx.doi.org/10.1016/j.lwt.2019.04.012
Plain language summary
Dairy protein hydrolysates contain peptides with recognized physiological activities. However, during digestion, these peptides are often digested before reaching their absorption site. To maximize health effects and support the development of bioactive ingredients, we have developed an encapsulation system that protects peptides during gastric transit and gradually releases them in the intestinal phase. The encapsulation system consists of a water-in-oil-in-water double emulsion. The peptide solution to be protected is dispersed in the form of fine droplets in larger oil droplets. This emulsion uses a unique oil composition. We compared the use of low-digestibility oils (jojoba, mineral) to high-digestibility oil (flax). We studied the release of peptides in a simulated digestion system. During the gastric phase, the double emulsion offers excellent protection, and only 5% to 20% of the peptides are released. We also demonstrated that peptides were released by simple diffusion and that diffusion rates were proportional to the hydrophobicity of the peptides and inversely proportional to the viscosity of the oil. In the intestinal phase, the release of peptides is directly associated with the digestibility of the oil used to produce the emulsion. The results of this study demonstrate the effectiveness of the double emulsion in protecting bioactive ingredients during gastric transit. In addition, the selection of the oil used to produce the emulsion makes it possible to control the rate of release in the intestinal phase.
Abstract
β-Lactoglobulin hydrolysate was encapsulated in water-in-oil-in-water (W1/O/W2) emulsions. The effects of digestible (linseed) and non-digestible (jojoba and mineral) oil phases on emulsion characteristics and peptide release in gastrointestinal conditions were compared. Peptide release was studied at gastric pH (3) and intestinal pH (7) in the absence of lipase and at intestinal pH (7) in the presence of lipase. Released peptides were analyzed by RP-HPLC and identified by LC-MS. The encapsulation efficiency of the three emulsions was over 90%. The W1/O/W2 emulsion produced from mineral oil had the highest droplet diameter. In the absence of lipase, the proportions of peptides released after 4 h of agitation (37 °C) were significantly lower at gastric pH (4.1%–18.8%) than at intestinal pH (10.6%–35.3%) and varied in the order mineral oil < linseed oil < jojoba oil. Peptide release was inversely correlated to oil viscosity and increased with peptide hydrophobicity. As expected, linseed oil was degraded by lipase at intestinal pH, and peptide release reached 100%. Jojoba and mineral oils were not degraded by lipase, and the proportion of released peptides was similar to that observed in the absence of lipase.