Identifying the physicochemical properties of α-lactalbumin-based platforms directing the gastro-intestinal bio-accessibility of lipophilic nutraceuticals

Edible protein-based platforms for delivery of lipophilic bioactives are increasingly investigated to help prevent, alleviate and even treat various aspects of human health. This study focuses on α-lactalbumin (ALA), as a potential platform for nano-complexation with various lipophilic compounds and their targeted and controlled release in the human gastro-intestine, with Capsaicin (CAP) from hot chili peppers as a model active ingredient.

The presentation will show various strategies to fabricate different ALA-based platforms that in turn show different capacity to render CAP bioaccessible in the human gut. To this end, holo and apo ALA-CAP nano-complexes and thermally induced aggregates of ALA-CAP were produced and characterized. ITC findings reveal the number of CAP binding sites in holo and apo ALA is equal to 1.57 ± 0.07 and 0.93 ± 0.08, respectively. UV-CD and Fluorescence spectroscopy elucidate some conformational changes upon binding and FRET phenomena that occurs between ALA and CAP, indicating an intimate interaction between them. Thermally induced ALA-CAP nano-colloids encapsulate CAP with efficiency ranging between 20%-60%, depending on ALA concentration and pH. In vitro dynamic gastrointestinal digestion of holo ALA-CAP complex exhibits a rapid increase in free CAP in the stomach, which confirms that CAP binds via weak interactions. Similarly, evidence will be presented on the digestive fate of thermally induced ALA-CAP nano-colloids. Overall, this study provides insights that extend the toolbox of food and health care professionals seeking the rational design and personalization of protein-based delivery systems, with ALA and CAP serving as model systems.