A high-performance liquid chromatographic method was developed for the analysis of capsaicinoid compounds, the pungent principles of capsicum fruits. A sequential simplex method was applied to optimize the chromatographic response function used to assess the quality of separation by varying the chromatographic parameters. The separation was achieved in 11 min using a C-8 column of 15-cm length and 4.6 mm diameter using a UV detector. A flow rate of 1.15 ml min -1 at a column temperature of 43.5˚C using 63.7% methanol in water gave the most efficient separation. The method was found to be suitable for the determination of the major capsaicinoid compounds in the capsicum samples.

No abstract

No abstract

Biopolymers obtained from renewable sources have been exploited in developing biomaterials with eco-friendly properties. Most biopolymers have some limitations because of their poor mechanical properties, high water solubility, or low transparencies. In this study, some biopolymers, that is, silk fibroin (SF) and rice starch (RS) were used as starting materials together with polyvinyl alcohol (PVA) as a film-former for preparing novel eco-friendly films. The film preparations were done by solution casting with two different sequences of blending and the film compositions were optimized. Results from UV, SEM, and film properties testing on mechanical properties, degree of swelling, water solubility, and also oxygen permeability indicated that all film properties depended on their compositions and order of blending. The PVA/RS film obtained is transparent with good mechanical properties and low water solubility. The addition of SF increases the permeability of oxygen and also the degradability of the films.

Membranes prepared by drying aqueous Bombyx mori silk fibroin (SF) solution and modified silk fibroin (MSF) solutions, prepared by adding the low molecular weight crosslinking agent, polyethylene glycol diglycidyl ether (PEGDE) MW 526, 0-10% w/w, were investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and UV-vis spectroscopy. Weight gain in aqueous solutions and their mechanical properties (tensile strength, elongation, and Young's modulus) were then characterized. SEM measurements revealed greater porosity in MSF membranes. IR spectra showed transformation from the largely a-helical/ random coil structures in SF membranes to predominantly b-sheet in MSF membranes. Results from UV-vis spectroscopy showed that the MSF membranes were largely insoluble within the pH range of 4-10. Water absorbability of the MSF membranes improved with increasing the amounts of cross-linker, up to 4%. The MSF membranes showed greater pliability and tenacity, but lower tensile strength, with increasing PEGDE concentrations. In the wet condition, PEGDE levels up to 4% can improve both tensile strength and tenacity of the MSF membrane, but higher levels (up to 10%) did not significantly change these properties.

No abstract

No abstract

The role of organic blends of silk fibroin (SF) and rice starch (RS) in bone composites based on inorganic hydroxyapatite (HA) is studied. The physical property of HA‐based composites prepared by using the sol–gel method from Ca(OH)2 and H3PO4 in ethanol and water solvent (4 : 1 volume ratio) could be improved by adding SF and RS (1 : 2 weight ratio) to HA (7 : 3 weight ratio). The Fourier transform infrared spectrometer spectrum shows that the SF and RS organic phases are blended homogeneously into the HA crystal structure. Addition of SF increases the pore size and surface area of the composites, as measured by Brunauer–Emmett–Teller method, but their pore volume is slightly decreased. The values of lattice parameters, crystallinity, and crystallite size, as determined from the field‐emission scanning electron microscope, transmission electron microscope, and X‐ray diffractometer results, increase after adding RS. The results are agreeable with the increase of their compressive strength and Young's modulus. Thus, the improved physical property of the prepared HA–SF/RS composites is better suited as bone‐filling material than the standard HA or HA‐based composites with either SF or RS only. Therefore, due to its low cost, biocompatibility, and nontoxicity, this innovative solution could be worth taken under consideration by the restorative dental and orthopedic implants industry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42722.