Soy Protein Isolate–β‐Cyclodextrin Microencapsulation Boosts Stability and Intestinal Delivery of α‐Linolenic Acid‐Rich Structured Lipids: Oxidation, Digestion, and Molecular Docking Evaluation

The previous study found that a structured lipid rich in α‐linolenic acid (ALA‐SL) is prone to oxidative rancidity due to its high degree of unsaturation. To improve its oxidative stability and targeted slow‐release behavior during gastrointestinal digestion, ALA‐SL microcapsules (ALA‐SLMs) were prepared by freeze‐drying in this study. Under optimal conditions, ALA‐SLMs exhibited an excellent embedding efficiency of 98.00% ± 0.46%, with an approximately spherical structure, particle size concentrated between 1 and 10 µm, and good uniformity verified by a span value of 1.92. After 60 days of storage at 4°C, 25°C, 40°C, and 60°C, the peroxide value (PV) of unencapsulated ALA‐SL was 1.02‐, 1.06‐, 1.01‐, and 1.11‐fold higher than that of ALA‐SLMs, respectively. In vitro simulated digestion demonstrated its characteristic intestinal sustained‐release behavior, which provides preliminary in vitro evidence that may favor enhanced intestinal absorption of α‐linolenic acid (ALA); however, further cellular or animal trials are required to quantitatively validate its actual in vivo bioavailability improvement. Molecular docking predicted that β‐cyclodextrin (β‐CD) only forms weak shallow non‐covalent complexes with ALA via cavity‐mouth hydrogen bonds, which offers limited molecular‐level protection for unsaturated fatty acids.