Oleogel From Basil Seed Oil for Quercetin Delivery: Physicochemical, Rheological, Thermal, and In Vitro Digestion Properties

Abstract

This study is aimed at developing and characterizing functional oleogels (OGs) based on Ocimum basilicum L. seed oil (a rich source of α-linolenic acid) structured with beeswax (5%–20%) for the effective delivery of quercetin. The formulation’s physicochemical properties, structural integrity, and release behavior under simulated gastrointestinal conditions were evaluated. Gel setting time was significantly (p < 0.05) reduced from 8.44 to 6.25 min by increasing the beeswax concentration from 5% to 20%, and oil binding capacity exceeded 99% in formulations containing ≥ 10% beeswax. As the wax concentration increased, the firmness of OGs increased significantly (p < 0.05) from 14.8 to 130 g, with the highest hardness observed at 20% beeswax. Rheological analysis confirmed gel-like viscoelastic behavior and formation of well-structured OGs using more than 5% oleogelator. FTIR spectra indicated physical interactions between quercetin and the wax–oil matrix. XRD analysis revealed β ′-polymorphic crystals (d = 4.18 and 3.76 Å), desirable for food applications. DSC confirmed enhanced thermal stability and absence of quercetin crystallinity in the OG matrix. In vitro release studies showed that oil structuring resulted in lower release of loaded bioactive in harsh gastric conditions (36% and 22% for OGs containing 5% and 20% oleogelator, respectively), thus promoting intestinal delivery (up to 71%). The release data were best fitted with the Kopcha kinetic model (R2 ≥ 0.96). These results highlight the potential of basil seed oil–based OGs as sustainable carriers for bioactive delivery in food and nutraceutical applications.