Extração e caracterização de gelatina de pele de tilapia e aplicação como agente encapsulante de oleo de salmão em microparticulas obtidas por coacervação complexa. / Extraction and characterization of fish skin gelatin and application as encapsulate agent of salmon oil in microparticles obtained by complex coacervation.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Two great challenges in the pisciculture production chain are the use of by-products generated during the fish processing and the production of more attractive microparticles for fish larvae feeding. The aim of this work was to extract and to characterize gelatin from tilapia skin to use it as a substitute of mammalian gelatins in the formation of matrix of microparticles, obtained by complex coacervation, containing salmon oil. Tilapia skin gelatin was obtained, characterized and compared to commercial pig gelatin as for gel strength (Dnqqo), texture profile, melting point, molecular weight distribution and proximate composition. Conditions of microparticles processing were also evaluated, their morphology and microstructure by optical and scanning electron microscope, mean diameter and encapsulation efficiency. Pig gelatin and one second lot of fish gelatin exhibited quite similar results of gel strength with values of 192,2 ± 2,9 g and 202,8 ± 3,7 g, respectively. Gel strength of first lot of fish gelatin (11,5 ± 0,7 g) was smaller than the second lot due to the lipid content slightly larger in the first lot. Pig gelatin presented an initial melting point larger (27,5°C) than first and second lots of fish gelatins (18,5°C and 24,0° C, respectively). Related to the molecular weight distribution, more degradation was observed in pig gelatin than fish gelatin. Higher agitation speed (14000 rpm) produced microparticles with core material constituted by smaller droplets of oil. The increase of the concentration of matrix polymeric material (5,0 and 7,5%) resulted in production of particles with irregular formats. The different gelatins used as matrix of microparticles did not cause significant alterations in the efficiencies of encapsulation, with values varying from 59,7 to 72,4%, as well as, the replacement of oleoresin of paprika + soy oil for salmon oil also did not produced significant differences among the microparticles regarding to this parameter. The mean diameter remained between 83 and 150 ?m considering all the particles produced. The application of salmon oil and fish gelatin did not impair the morphology of microparticles that kept the characteristic spherical format and the wall integrity. Considering the obtained results, it is possible to substitute commercial pig gelatin for tilapia skin gelatin and oleoresin of paprika + soybean oil for salmon oil, allowing a production of microparticles rich in ômega 3 oil and possibly with a greater attractiveness in the feeding of fish larvae.

ASSUNTO(S)

gelatina de pele de peixe coacervação complexa complex coacervation oreochromis niloticus oleo de salmão salmon oil microencapsulação fish skin gelatin microencapsulation oreochromis niloticus

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