Tuning lipid digestibility and β-carotene bioaccessibility via β-sitosterol/γ-oryzanol ratios in oleogels.

Abstract

Poor bioavailability of lipophilic nutrients remains a major challenge in oral delivery. This study investigated how β-sitosterol/γ-oryzanol (SiOr) ratios in canola oil-based oleogels modulate mechanical properties, lipid digestion, and β-carotene bioaccessibility. Among the tested formulations, Si4Or6 exhibited the highest hardness (11.90 ± 0.98 N) and the lowest extent of lipolysis (46.6 ± 4.2%), indicating enhanced resistance to lipolysis. While liquid canola oil underwent rapid hydrolysis, oil gelation significantly delayed lipolysis, although final free fatty acid release remained comparable across most formulations. Conversely, β-carotene bioaccessibility increased progressively with γ-oryzanol content, from 39.0 ± 1.2% in Si10 to 56.0 ± 4.8% in Or10, independent of gel hardness. These findings demonstrate that the Si:Or ratio differentially regulates lipolysis and β-carotene bioaccessibility, providing a rational framework for tailoring oleogel-based delivery systems to achieve controlled lipolysis of lipophilic bioactive molecules for functional food and nutraceutical applications.