Native starch as in situ binder for continuous twin screw wet granulation.

The use of native starch as in situ binder in a continuous twin screw wet granulation process was studied. Gelatinization of pea starch occurred in the barrel of the granulator using a poorly soluble excipient (anhydrous dicalcium phosphate), but the degree of gelatinization depended on the liquid-to-solid ratio, the granule heating and the screw configuration. Furthermore, the degree of starch gelatinization was correlated with the granule quality: higher binder efficiency was observed in runs where starch was more gelatinized. SEM and PLOM images showed experimental runs which resulted in completely gelatinized starch. Other starch types (maize, potato and wheat starch) could also be gelatinized when processed above a critical barrel temperature for gelatinization. This barrel temperature was different for all starches. In situ starch gelatinization was also investigated in combination with a highly soluble excipient (mannitol). The lower granule friability observed using pure mannitol compared to a mannitol/starch mixture indicated that starch did not contribute to the binding, hence starch did not gelatinize during processing. The study showed that native starch can be considered as a promising in situ binder for continuous twin screw wet granulation of a poorly soluble formulation.

Phenolic compounds and anti-oxidant capacity of twelve morphologically heterogeneous bamboo species.

INTRODUCTION: Despite the growing interest in the use of bamboo for both food and health-related applications because it provides a rich source of anti-oxidants, there is still a lack of information on the responsible secondary metabolites of the great variety of bamboo species. OBJECTIVE: To extend the knowledge on secondary metabolites of different bamboo species and to link anti-oxidant capacity with the different classes of phenolic compounds that are present in the leaves. METHODOLOGY: Chromatographic profiles of 12 morphological heterogeneous bamboo species from different genera were recorded using HPLC-DAD (diode array detector) and LC-MS/MS. In addition, the in vitro anti-oxidant capacity was evaluated using a variety of anti-oxidant assays (1,1-diphenyl-2-picrylhydrazyl, Trolox-equivalent anti-oxidant capacity and oxygen radical absorbance capacity). Using partial least square (PLS) analysis as a chemometric method, the anti-oxidant capacity could be linked to specific groups of polyphenols. RESULTS: Flavones and phenolic acids are the two main polyphenolic classes present in the leaf extracts of the 12 selected bamboo species. Luteolin derivatives and phenolic acids were identified as the most potent anti-oxidants. CONCLUSION: The most abundant classes of phenolic compounds present in a selection of bamboo species were flavone glycosides and phenolic acids. Luteolin flavones and phenolic acids are the main anti-oxidant phenolic compounds in bamboo leaf extract. The information obtained in this study provides further support for the development of bamboo-based anti-oxidant food applications and food supplements.

Lyophilization of protein-loaded polyelectrolyte microcapsules.

PURPOSE: To evaluate if lyophilization can be used to obtain a dry formulation of polyelectrolyte microcapsules, which have emerged as a new class of microparticles for the encapsulation and delivery of biomacromolecules. METHODS: Microcapsules composed of dextran sulfate and poly-L-arginine were obtained by coating CaCO(3) microparticles by means of the layer-by-layer technique. Microcapsules were lyophilized using different stabilizers; intactness was checked by CLSM and SEM. Horseradish peroxidase was encapsulated as model enzyme and retained activity after freeze-drying was determined using a fluorescence assay. Ovalbumin was encapsulated as model antigen; immunogenicity after lyophilization was evaluated in vitro by a T-cell proliferation assay and in vivo by measuring the antibody titer in mice. RESULTS: The results clearly demonstrate the necessity of using polyols in the formulation to prevent rupture of the microcapsules and to preserve the activity of encapsulated enzymes. Lyophilized microcapsules appeared as a promising adjuvant for antigen delivery, as both in vitro as in vivo assays showed higher immune activation compared to free antigen. CONCLUSIONS: Lyophilization is a promising strategy towards improved stability of protein-loaded microcapsules.