Release profile of amino acids encapsulated in solid lipid particles during in vitro oro-gastrointestinal digestion

• Published in: Food research international 2024-08, Vol.190, p.114605, Article 114605
• Main Authors: Rajendrakumar, Sharmitha, Beaumal, Valérie, Kermarrec, Alice, Lopez, Christelle, Novales, Bruno, Rabesona, Hanitra, Simongiovanni, Aude, Demersay, Tristan Chalvon, Marze, Sébastien
• Format: Article
• Language: English
• Subjects: Amino acids; Amino Acids - chemistry; Amino Acids - metabolism; Amino Acids, Branched-Chain - metabolism; Animal biology; Animals; Digestion; Food and Nutrition; Gastrointestinal Tract - metabolism; In vitro digestion; Life Sciences; Lipids - chemistry; Lysine - chemistry; Lysine - metabolism; Particle Size; Physicochemical properties; Release kinetics; Solid lipid particles; Swine; Tryptophan - chemistry; Tryptophan - metabolism; Veterinary medicine and animal Health
• ISSN: 0963-9969; 1873-7145; 1873-7145
• DOI: 10.1016/j.foodres.2024.114605

[Display omitted] •Solid lipid particles SLP containing various amino acids were fully characterized.•Different particle size fractions were submitted to oro-gastrointestinal digestion.•Amino acid release was high during the gastric phase, and depended on particle size.•SLP hydrolysis during digestion did not control amino acid release kinetics.•SLP crystalline structure was found to be the main factor controlling the release. Some amino acids are known to mediate immune responses through gut microbiota metabolism in both humans and monogastric animals. However, through the diet, most free amino acids are absorbed in the small intestine and only a small quantity reaches the microbiota-rich colon. To enhance microbial metabolism of amino acids and their potential health benefits, encapsulation strategies are developed for their protection and delivery to the colon. So far, the main encapsulation systems for amino acids are based on solid lipid particles, but their fate within the digestive tract has never been fully clarified. In this study, we investigated the release of various amino acids (branched-chain amino acid mixture, or lysine, or tryptophan) loaded in solid lipid particles during in vitro oro-gastrointestinal digestion mimicking the piglet. The loaded solid lipid particles were fully characterized for their composition, thermal behavior, molecular structure, crystalline state, surface morphology, and particle size distribution. Moreover, we investigated the effect of particle size by sieving solid lipid particles into two non-overlapping size fractions. We found that amino acid release was high during the gastric phase of digestion, mainly controlled by physical parameters, namely particle size and crystalline state including surface morphology. Large particle size and/or smooth ordered particle indeed led to slower and lower release. Although lipid hydrolysis was significant during the intestinal phase of digestion, the impact of the crystalline state and surface morphology was also observed in the absence of enzymes, pointing to a dominant water/solute diffusion mechanism through these porous solid lipid particles.