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- Curi, Cecilia
(författare)
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Development of bixin formulations. Extraction, microencapsulation, dispersibility and photostability
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aril that covers the seeds of the plant species Bixa orellana is composed of the natural colorants bixin and norbixin, phenolic components and native carbohydrates composed of hemicellulose, starch, and a small fraction of proteins. Bixin is a hydrophobic carotenoid that is water insoluble and is mostly used for coloring oil-based formulations. This thesis presents the development of different bixin formulations to be used as coloring agents in aqueous continuous-based products. Any colorant formulation needs the colorant to be available and extraction feasible. The first stage of the thesis consisted of the morphological and photochemical characterization of Bixa orellana fruits that were collected from Los Yungas of La Paz, Bolivia at different altitudes. The water content, seed weight, and the amount of bixin, norbixin and native carbohydrates were quantified. The aril of the seeds was extracted using a mild alkaline extraction method to obtain an aqueous-dispersible extract that was directly analyzed by meas of solvent dissolution and further injection into a HPLC or by means of analysis using spectroscopic techniques.In a second stage, the use of the mild alkaline base was used as a method to obtain aqueous dispersions that were mixed with an encapsulating agent. This mixture was spray dried to obtain colorant microcapsules. Micro encapsulation was applied to obtain bixin aqueous-dispersible formulations and offer protection to the colorant against light degradation. The impact of the native carbohydrates was evaluated as an encapsulating agent and as protection against bixin light degradation. The encapsulation efficiency of bixin by different wall materials was compared. Light stability experiments were performed on Bixin microcapsules (powders) and unprotected colorants. The results show that lower sensitivity towards light was obtained for microencapsulated samples. Moreover, light stability of annatto extracts applied to gummy candies was evaluated. The results show faster color decay for samples containing lower colorant concentrations for the same degradation rates. Sensorial analysis showed good acceptability of the color of the candies presented as pictures to the panelists.
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