Abstract

SANCHEZ-MOLINA, Deisy; VARGAS-PORRAS, Mayra; ORTEGA-TORO, Rodrigo  and  PINEROS-CASTRO, Yineth. Extraction and encapsulation of phenolic compounds from rice hus. Rev. colomb. cienc. quim. farm. [online]. 2018, vol.47, n.3, pp.410-423. ISSN 0034-7418.  https://doi.org/10.15446/rcciquifa.v47n3.77373.

Currently, the use of agro-industrial by-products is of vital importance. The aim of the present work was to study an alternative of valorisation of the rice husk, by extraction and encapsulation of phenolic compounds from the husks. This process was carried out in a batch reactor with mechanical stirring at 453.15 K and 1 MPa for 1 h, water was used as the solvent. Microencapsulation of the extract components was evaluated by lyophilisation using maltodextrin at different proportions as encapsulating material. The aqueous extracts showed a pH of 3.7, contained phenolic compounds of 8.2 mg gallic acid/g of husk, and an antioxidant activity of 14.6 mg Eq.trolox/g of husk. By infrared spectroscopy analysis, representative bands of functional groups present in the phenolic compounds, recognised for their antioxidant activity, were identified. The encapsulation efficiency was 99.8 % using 14.3 % maltodextrin; capsules were obtained with 10.08 mg phenols/g capsules and a particle size suitable for the release and retention of phenolic compounds of 63 μm. Subsequently, the semi-crystalline structure of the capsules was studied by X-ray diffraction. To conclude, these antioxidant microcapsules may be suitable for use in the pharmaceutical or food industry as a component of food packaging.

Keywords : By-product; antioxidant activity; phenolic compounds; freeze-drying; maltodextrin.

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