Development of an HPLC-PDA Method for the Determination of Capsanthin, Zeaxanthin, Lutein, ß-Cryptoxanthin and ß-Carotene Simultaneously in Chili Peppers and Products.

For the better standardization and widespread application of the determination method of carotenoids in both chili peppers and their products, this work reports for the first time the simultaneous determination of five main carotenoids, including capsanthin, zeaxanthin, lutein, ß-cryptoxanthin and ß-carotene in chili peppers and their products, with optimized extraction and the high-performance liquid chromatography (HPLC) method. All parameters in the methodological evaluation were found to be in good stability, recovery and accuracy compliance with the reference values; the R coefficients for the calibration curves were more than 0.998; and the LODs and LOQs varied from 0.020 to 0.063 and from 0.067 to 0.209 mg/L, respectively. The characterization of five carotenoids in chili peppers and their products passed all the required validation criteria. The method was applied in the determination of carotenoids in nine fresh chili peppers and seven chili pepper products.

A phase diagram of morphologies for anisotropic particles sculpted from emulsions.

HYPOTHESIS: A micron-scale oil-in-water emulsion droplet frozen in the presence of surfactants can be induced to eject the crystallizing solid from its liquid precursor. This dynamic process produces highly elongated solids whose shape depends critically on the rate of crystallization and the interfacial properties of the tri-phase system. EXPERIMENT: By systematically varying the surfactant concentration and cooling protocol, including quenching from different temperatures as well as directly controlling the cooling rate, we map out the space of possible particle morphologies as a function of experimental control parameters. These results are analyzed using a non-equilibrium Monte Carlo model where crystallization rate and interfacial energies can be specified explicitly. FINDINGS: Our model successfully predicts the geometry of the resulting particles as well as emergent phenomena including how the particle shape depends on nucleation site and deformation of the precursor droplet during crystallization.

Crystal Comets: A Geometric Model for Sculpting Anisotropic Particles from Emulsions.

Microscopic high aspect ratio particles have many applications including enhanced delivery of active ingredients and food stability. Here, we develop a simple, scalable process that produces particles with a continuously controllable aspect ratio. Oil-in-water emulsion droplets are quenched and crystallize in the presence of surfactants that facilitate the ejection of the solid oil phase from its liquid precursor. Tuning the ejection and crystallization rates to be comparable, by adjusting the surfactant concentration and quench depth, promotes anisotropic particle growth by continuously ejecting solidified oil from the precursor droplet as the crystallization proceeds. We predict the accessible morphologies using an analytical geometric model that indicates a nonconstant contact angle during the crystallization process. We see that the crystal aspect ratio is dependent on the surfactant concentration, which can be explained as a variation of the maximum growth angle achieved during crystallization.