Stability and gastrointestinal digestion behaviour of theaflavins encapsulated in W/O Pickering emulsions
Yuting Lu, Yuanjie Wu, Yijia Liu, Haoren Wu, Chaoxi Zeng, Si Qin, Meng Shi
Abstract
Theaflavins (TFs) are naturally bioactive compounds with low stability and poor bioavailability. In this study, the stability of TFs during storage at 25 °C for 21 d and thermal treatments at 65 °C, 85 °C and 105 °C for 0.5–4 h of water in oil (W/O) Pickering emulsions composed of TFs (0–9 mg/g), ursolic acid, oil and water were investigated. The TFs incorporation at 9 mg/g had the smallest droplet size and the highest G′ and G″ values. After storage for 21 days and thermal treatment at 105 °C for 4 h, the TFs retention in emulsions (9 mg/g) were 1.2-fold and 1.4-fold higher than aqueous solution, respectively, which might be attributed to the encapsulation of TFs in water droplets. During digestion, TFs emulsions provided a greater surface area for lipid digestion and led to a higher release of free fatty acids than emulsions without TFs. Moreover, there was sustained release of TFs in the emulsion, resulting in significantly enhanced TFs bioaccessibility (57.8 ± 9.2%) compared with aqueous solution (17.7 ± 1.1%) and Oil-Water mixture (32.6 ± 2.3%) after intestinal digestion. This study provides insights for food industry in designing W/O emulsion systems for the delivery of hydrophilic bioactive components. • High theaflavins concentration obtained smaller Pickering emulsion droplets. • Theaflavins Pickering emulsion had good thermal and storage stability. • Pickering emulsion achieved sustained release of theaflavins. • Pickering emulsion significantly enhanced the theaflavins bioaccessibility.