Tuning of Molecular Interactions between Zein and Tannic Acid to Modify Sunflower Sporopollenin Exine Capsules: Enhanced Stability and Targeted Delivery of Bioactive Macromolecules.

There are multiple obstacles for the storage and digestion of orally administered bioactive macromolecules. This study developed a low-cost and sustained-release delivery system (sporopollenin exine capsules with zein/tannic acid modification) of proteins with excellent storage stability, and at the same time provided insights into the sustained-release mechanism through exploring the interaction between zein and tannic acid (TA). ß-Galactosidase (ß-Gal) was utilized as a model protein and loaded into sporopollenin exine capsules (SECs), which were then coated with the zein/TA system. Under the optimized zein/TA conditions, the zein/TA system showed better performance than the zein alone system in the sustained release of ß-Gal, with the residual activity of about 70.26% after 24 h of simulated digestion. Evaluation of the storage stability demonstrated a ß-Gal residual activity of nearly 90% for 28 days at 25 °C. Additionally, FTIR analysis demonstrated that the stability of the zein/TA system depends on both hydrogen bonding and certain covalent bonding through the Schiff-base reaction, and the sustained release is regulated by the bonding strength.

Designable Carboxymethylpachymaran/Metal Ion Architecture on Sunflower Sporopollenin Exine Capsules as Delivery Vehicles for Bioactive Macromolecules.

There are multiple obstacles in the gastrointestinal tract (GIT) for oral administration of bioactive macromolecules. Here, we engineered an oral delivery vehicle (sporopollenin exine capsules with carboxymethylpachymaran (CMP)/metal ion modification) with targeted release based on food-grade ingredients and processing operations. Then, the interaction and binding mechanisms between CMP and metal ions in the vehicle were investigated. By using ß-galactosidase (ß-Gal) as a model protein, the systems were characterized for the surface morphology and monitored by the in vitro release profile of ß-Gal. Notably, the CMP/metal ion systems not only markedly decreased the CMP dosage but also achieved a valid long-term release compared with the previously reported CMP system. Among all the systems, the CMP/3% AlCl3 system showed the best ability to control the release with the maximum residual activity of ß-Gal at nearly 72% after 24 h of treatment. Subsequently, the interaction mechanism between CMP and metal ions within the system was characterized by the perspectives of microstructure, rheological properties, and spectroscopy characteristics. The results indicated that the low pH conditions are conducive to the further cross-linking of CMP and metal ions, resulting in a high gel strength and thus a dense structure, which can impact the controlled release of ß-Gal in the GIT. Overall, the system may be utilized in the administration of medical and functional foods, specifically for the delivery of bioactive proteins via the oral route.

Carboxymethylpachymaran entrapped plant-based hollow microcapsules for delivery and stabilization of ß-galactosidase.

ß-Galactosidase (ß-Gal) as a dietary supplement can alleviate symptoms of lactose intolerance. However, ß-Gal is deactivated due to the highly acidic conditions and proteases in the digestive tract. In this work, ß-Gal was encapsulated into L. clavatum sporopollenin exine capsules (SECs) to fabricate an oral-controlled release system and increase the stability of ß-Gal in the digestive tract. The SEC extraction process was optimized. A 3-hour vacuum loading was determined as the optimal loading time. Five different initial ratios of SECs : ß-Gal were optimized with the maximum enzyme retention rate reaching 79.40 ± 1.96%. Furthermore, ß-Gal-loaded SECs entrapped in carboxymethylpachymaran (CMP) could control the release of ß-Gal under simulated gastrointestinal conditions (SGC). The optimal enzyme retention rate reached 65.33 ± 1.46% within 24 h under SGC. Collectively, these results indicated that the entrapped SECs could be used as an effective oral delivery vehicle of ß-Gal to improve its performance as a dietary supplement in the digestion of lactose.