Production of microencapsulados of starch with recobrimento in bed fluidizado / Produção de microencapsulados de amido com recobrimento em leito fluidizado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

Thin polymeric layers, when applied to microcapsules, can increase the degree of protection and control the release of the contents. Starch microcapsules containing gelatin as binding material, obtained by spray drying, were filled with commercial fish oil by adsorption, and subsequently encapsulated, aimed at forming a film either with gelatin or with a mixture of ca1ciurn chloride and pectin with a low degree of esterification, the encapsulation process being conducted in a fluidized bed system, specifically developed to control the thickness of the walI material. The products obtained were submitted to a shelf life study in an incubator at 45°C, removing samples every two days for a period of 10 days. After extraction, the peroxide value of the samples was quantified. The morphological characterization of the capsules was accompanied by a determination of the average size, particle size distribution and by observation under a scanning electron microscope. The encapsulation yield was determined after drying. A comparison of the average size of the encapsulated particles with that of the non encapsulated ones, which presented an average size of 59.30flm, showed an increase in size of the encapsulated particles. Encapsulation with gelatin increased the average size to 88.4flm, whilst encapsulation with 0.4 and 0.8% ca1cium pectate (% in relation to the dry weight of the product), presented an average size of 94.17 and 120.43flm respectively. The morphology of the encapsulated particles indicated that the walI was not homogeneous, an accurnulation of granules during the process being observed. However, the interstices between the granules were shown to be filled with walI material. The encapsulation yield was 88.87% for the particles encapsulated with gelatin, and 83.81 and 85.92% for those encapsulated in 0.4 and 0.8% ca1cium pectate respectively. Quantification of the peroxides in the samples analyzed, indicated a rapid eterioration of the core material for alI the encapsulated samples. The great susceptibility of fish oil to oxidation and the intense exposure to an air current during the encapsulation process, could have been responsible for the acceleration of the auto-oxidation process

ASSUNTO(S)

leito fluidizado (pirometalurgia) starch estabilidade microencapsulados microencapsulação amido stability

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