Robust W/O/W Emulsion Stabilized by Genipin-Cross-Linked Sugar Beet Pectin-Bovine Serum Albumin Nanoparticles: Co-encapsulation of Betanin and Curcumin.

Betanin and curcumin hold promise as natural colorants and antioxidants for food purposes due to their anti-hypertensive, anti-inflammation, and anti-tumor effects. However, the thermal stability and bioavailability of betanin and curcumin still need improvement. Here, we fabricated sugar beet pectin-bovine serum albumin nanoparticles (SBNPs) with a mean particle size of 180 ± 5.2 nm through a genipin cross-linking strategy to stabilize a type of Pickering water-in-oil-in-water (W/O/W) emulsion and co-encapsulated betanin and curcumin. First, the W1/O emulsion was homogenized with gelatin (the gelling agent) in the water phase and polyglycerol polyricinoleate (a lipophilic surfactant) in the oil phase. Later, W1/O was homogenized with another water phase containing SBNPs. The microstructure of the emulsion was regulated by the particle concentration (c) and W1/O volume fraction (Φ), especially the gel-like high internal phase emulsions were formed at the Φ up to 70%. In this case, betanin was encapsulated in the internal water phase (encapsulation efficiency = 65.3%), whereas curcumin was in the medium-chain triglyceride (encapsulation efficiency = 84.1%). Meanwhile, the shelf stability of betanin and curcumin was improved. Furthermore, the stability of bioactive compounds was potentiated by an emulsion gel in simulated gastrointestinal digestion, resulting in higher bioaccessibility. The aforementioned results suggest that SBNP-stabilized Pickering W/O/W emulsions could be a potential alternative to co-encapsulate betanin and curcumin with enhancement of shelf stability and bioaccessibility.

Enzymatic synthesis of non-digestible oligosaccharide catalyzed by dextransucrase and dextranase from maltose acceptor reaction.

Non-digestible oligosaccharides have wide food industrial applications as dietary fibers and prebiotics. The aim of this study is to realize the effective biosynthesis of isomalto-oligosaccharides (IMOs) and reduce the production of by-product dextran. In the presence of acceptors improved the dextransucrase reaction shifting to oligosaccharides formation but a number of by-products dextran appeared. Maltose acceptor performed stronger inhibition behaviors in dextran synthesis than lactose and glucose acceptor due to its higher efficiencies. Acceptors had no influence on the structure of by-product dextran which mainly composed of α-(1,6)-glycosidic linkages and low α-(1,3)-glycosidic branch. In addition, the Mw and contents of IMOs and oligodextrans synthesized by dual-enzyme were hard to control. Addition of maltose acceptor in the dual-enzyme reaction, the adequate dextranase preferentially degraded dextran than the acceptor products to yield the IMOs. Results indicated that the combined use of the dual-enzyme and the maltose acceptor is a simple and effective method to promote the high-quality of functional IMOs.