Inclusion complex of catechin (CAT) with β-cyclodextrin (β-CD) was prepared using co-precipitation method to enhance antioxidant stability of CAT and the physicochemical properties of the inclusion complex were studied. The CAT/β-CD inclusion complex was analyzed through phase solubility study, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Phase solubility study indicated that CAT and β-CD formed 1:1 stoichiometric inclusion complex. Results of FT-IR indicated that CAT was stabilized in β-CD cavity by intra-molecular hydrogen bonds. Results of DSC and SEM proved that CAT/β-CD inclusion complex formed. XRD results showed that the formation of new solid crystalline phases in the CAT/β-CD inclusion complex. CAT was effectively protected through encapsulation into β-CD and the antioxidant stability of CAT was improved after encapsulation. In addition, the release behavior of CAT from the inclusion complex increased with increasing of the temperature. Propiedades fisicoquímicas del complejo de inclusión de catequina/β-ciclodextrina obtenido por coprecipitación RESUMEN En el presente estudio se obtuvo el complejo de inclusión de catequina (CAT) con β-ciclodextrina (β-CD) utilizando el método de coprecipitación con el propósito de mejorar la estabilidad antioxidante del CAT. Posteriormente se estudiaron las propiedades fisicoquímicas del complejo de inclusión resultante. Para analizar el complejo de inclusión CAT/β-CD se emplearon los siguientes estudios: estudio de solubilidad de fase, espectroscopia infrarroja transformada de Fourier (FT-IR), calorimetría diferencial de barrido (DSC), microscopía electrónica de barrido (SEM) y difracción de rayos X (DRX). El estudio de solubilidad de fase mostró que el CAT y la β-CD formaron un complejo de inclusión estequiométrica de 1:1. Por su parte, los resultados de FT-IR indicaron que en la cavidad β-CD el CAT fue estabilizado por enlaces de hidrógeno intramoleculares. Los resultados aportados por la DSC y la SEM demostraron que se formó un complejo de inclusión CAT/β-CD. Los resultados de la DRX dieron cuenta de la formación de nuevas fases cristalinas sólidas en el complejo de inclusión CAT/β-CD. El CAT se protegió eficazmente mediante la encapsulación en la β-CD y su estabilidad antioxidante mejoró después de ocurrir la encapsulación. Además, el comportamiento de liberación del CAT a partir del complejo de inclusión se incrementó con el aumento de la temperatura.

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Lutein is a carotenoid and has important physiological and antioxidant activity, but its poor dispersity in water and ease of oxidation impede applications. In this paper, encapsulation of lutein into starch nanoparticles is achieved by preparing starch‐lutein nanoparticles via nanoprecipitation. Lutein content in the nanoparticles reaches 13.2 mg g−1 when 90 mg lutein is added into 50 mL 1% (w/v) starch paste. Starch‐lutein nanoparticles provide preservation for lutein from chemical oxidation so that the lutein in starch‐nanoparticles oxidizes with a speed only about 25% when compared to pure lutein. In addition, the dispersity of lutein in water was considerably improved, and the aqueous dispersion of the starch‐lutein nanoparticles can remain stable for 30 days. X‐ray diffraction analysis suggests that lutein might form a complex with amylose.

In the present work, needle-shaped cellulose nanocrystals (CNCs) were prepared from commercial microcrystalline cellulose (MCC) through esterification and ultrasound treatment. The prepared CNCs were characterised by using Fourier transform infrared, degree of substitution (DS), dynamic light scattering, scanning electron microscopy and X-ray diffraction. The results revealed that the ultrasound disintegration of MCC was significantly improved after the esterification with maleic anhydride and the ultrasound treatment did not affect DS of the CNCs. With increasing power of the ultrasound treatment, smaller CNCs with narrower size distribution could be obtained. Average diameter and length of the CNCs could reach ∼14 and ∼180 nm, respectively. Furthermore, the crystal structure of cellulose was not changed during the esterification and ultrasound treatment and crystallinity of the CNCs increased comparing with MCC.

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