Calcium-alginate coated, whey protein-based microspheres: preparation, some properties and opportunities

Effect of Molecules' Physicochemical Properties on Whey Protein/Alginate Hydrogel Rheology, Microstructure and Release Profile

The encapsulation of molecules with different physicochemical properties (theophylline, blue dextran, salicylic acid and insulin) in whey protein (WP) and alginate (ALG) microparticles (MP) for oral administration was studied. MP based on WP/ALG were prepared by a cold gelation technique and coated with WP solution after reticulation. Molecules influenced polymer solution viscosity and elasticity, resulting in differences regarding encapsulation efficiency (from 23 to 100%), MP structure and swelling (>10%) and in terms of pH tested. Molecule release was due to diffusion and/or erosion of MP and was very dependent on the substance encapsulated. All the loaded MP were successfully coated, but variation in coating thickness (from 68 to 146 µm) and function of the molecules encapsulated resulted in differences in molecule release (5 to 80% in 1 h). Gel rheology modification, due to interactions between WP, ALG, calcium and other substances, was responsible for the highlighted differences. Measuring rheologic parameters before extrusion and reticulation appeared to be one of the most important aspects to study in order to successfully develop a vector with optimal biopharmaceutical properties. Our vector seems to be more appropriate for anionic high-molecular-weight substances, leading to high viscosity and elasticity and to MP enabling gastroresistance and controlled release of molecules at intestinal pH.

Matrices-charges of agar-alginate crosslinked microcapsules via o/w microemulsion: A non-spore forming probiotic bacteria encapsulation system for extensive viability

Non-spore forming probiotic bacteria tend to diminish their activity under adverse conditions. This leads to the difficulty of delivery in animal body system as well as the feed pelleting process. The present work proposes the microcapsule networks based on polymer matrices and charges under ionic crosslink to encapsulate probiotic for an extensive stability in adverse conditions. The combination of agar (AG) and alginate (AL) is a good model to combine agar matrices and alginate charges under ionic crosslink through o/w emulsion system for probiotic incorporation. By simply mixing Lactobacillus plantarum MB001(LPMB001) with AL and AG containing few drops of soybean oil, a stable o/w microemulsion can be obtained. The addition of calcium chloride favors the ionic crosslink among AG matrices resulting in LPMB001/AG-AL microcapsules. In vitro studies indicate the survival of LPMB001 and the slow release even after treatment in adverse conditions. This microencapsulation prolongs LPMB001 viability under the heat treatment and the storage conditions and this designates the potential feed processing. The present work for the first time shows how we can combine polymer matrices and charges to protect probiotic from the adverse conditions which is simple and practical for the process of dietary supplementation.

Development of a microencapsulated probiotic containing Pediococcus acidilactici WU222001 against avian pathogenic Escherichia coli

Background and Aim

Probiotics are beneficial microorganisms for humans and animals. In this study, we developed a microencapsulated probiotic with antibacterial activity against avian pathogenic Escherichia coli (APEC).

Materials and Methods

Alignment of the 16S rRNA sequences of the isolate WU222001 with those deposited in GenBank revealed that the isolate was Pediococcus acidilactici with 99.6% homology. This bacterium was characterized as a probiotic based on its tolerance toward in vitro gastrointestinal tract (GIT) conditions, hydrophobicity, and auto-aggregation. The antibacterial activity of the probiotic's culture supernatant against APEC was investigated using a broth microdilution assay. Pediococcus acidilactici was microencapsulated using sodium alginate and agar with diameters ranging from 47 to 61 μm. Then, physicochemical characteristics and stability of the microcapsules were determined.

Results

The isolate was characterized as a probiotic based on its resistance to low pH, bile salts, and pancreatin, with relative values of 79.2%, 70.95%, and 90.64%, respectively. Furthermore, the bacterium exhibited 79.56% auto-aggregation and 55.25% hydrophobicity at 24 h. The probiotic's culture supernatant exhibited strong antibacterial activity against clinical APEC isolates with minimum inhibitory concentration and minimum bactericidal concentration of 12.5% and 25% v/v, respectively. Microencapsulation-enhanced bacterial viability in GIT compared to free cells. Moreover, 89.65% of the encapsulated cells were released into the simulated intestinal fluid within 4 h. The viable count in microcapsules was 63.19% after 3 months of storage at 4°C.

Conclusion

The results indicated that the culture supernatant of P. acidilactici inhibited the growth of APEC. In addition, microencapsulation extends the viability of P. acidilactici under harsh conditions, indicating its potential application in the feed production.

Development and characterization of coated-microparticles based on whey protein/alginate using the Encapsulator device

The aim of this study is to prepare whey protein (WP)-based microparticles (MP) using the Encapsulator(®) device. The viscosity dependence of the extrusion device required to mix WP with a food-grade and less viscous polymer. Mixed WP/ALG MP were obtained with the optimized WP/alginate (ALG) ratio (62/38). These particles were further coated with WP or ALG using non-traumatic and solvent-free coating process developed in this study. Size and morphology of coated and uncoated MP were determined. Then, swelling and degradation (WP release) of formulations were investigated in pH 1.2 and 7.5 buffers and in simulated gastric and intestinal fluids (SGF, SIF) and compared to pure ALG and pure WP particle behaviours. At pH 1.2, pure ALG shrank and pure WP swelled, whereas the sizes of mixed WP/ALG matrix were stable. In SGF, WP/ALG MP resisted to pepsin degradation compare to pure WP particles due to ALG shrinkage which limited pepsin diffusion within particles. Coating addition with WP or ALG slowed down pepsin degradation. At pH 7.5, WP/ALG particles were rapidly degraded due to ALG sensitivity but the addition of a WP coating limited effectively the swelling and the degradation of MP. In SIF, pancreatin accelerated MP degradation but ALG-coated MP exhibited interesting robustness. These results confirmed the interest and the feasibility to produce coated WP-based MP which could be a potential orally controlled release drug delivery system.

Production and characterization of lipid microparticles produced by spray cooling encapsulating a low molar mass hydrophilic compound

The objective of this research was to produce and characterize lipid particles (MpLs) that may be used as carriers of high amounts of hydrophilic core and evaluate the influence of the core amount on the performance of lipid microparticles. The MpLs were produced by spray cooling from solid and liquid lipid mixtures (stearic and oleic fatty acids and partly hydrogenated vegetable fat) containing glucose solution as core and soy lecithin as surfactant. The performance of MpLs was evaluated by means of the effective amount of encapsulated core, the core amount present on the surface of MpLs (superficial glucose) and the core release profile in aqueous solution. Morphological observations showed that MpLs presented spherical shape and a rugged and continuous surface, and an average diameter between 25 and 32 µm. The effective amount of encapsulated core was greater than 78% for all formulations evaluated. Larger amounts of superficial glucose were found in formulations in which more concentrated glucose solutions were used, regardless of the glucose lipid-solution ratio. The release results showed that core retention was significantly influenced by the glucose solution concentration, whereas release modulation was influenced by the glucose lipid-solution ratio.

In vitro analysis of protection of the enzyme bile salt hydrolase against enteric conditions by whey protein-gum arabic microencapsulation

The interest in efficient intestinal delivery of health-promoting substances is increasing. However, the delivery of vulnerable substances such as enzymes requires specific attention. The transit through the stomach, where the pH is very low, can be detrimental to the enzymatic activity of the protein to be delivered. Here, we describe the microencapsulation of the model enzyme bile salt hydrolase (Bsh) using whey protein-gum arabic microencapsulates for food-grade and targeted enzyme delivery in the proximal region of the small intestine. Furthermore, the efficacy of enteric coating microencapsulates for site-specific enzyme delivery was compared in vitro with living Lactobacillus plantarum WCFS1 bacteria that endogenously produce the Bsh enzyme. Microencapsulates allowed highly effective protection of the enzyme under gastric conditions. Moreover, Bsh release under intestinal conditions appeared to be very efficient, although in the presence of pancreatin, the Bsh activity decreased in time due to proteolytic degradation. In comparison, L. plantarum appeared to be capable to withstand gastric conditions as well as pancreatin challenge. Delivery using encapsulates and live bacteria each have different (dis)advantages that are discussed. In conclusion, live bacteria and food-grade microencapsulates provide alternatives for dedicated enteric delivery of specific enzymes, and the choice of enzyme to be delivered may determine which mode of delivery is most suitable.