Retenção de óleo de café verde em complexos coacervados de proteínas concentradas do soro de leite ou soja e goma arábica
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2014-05-09
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Universidade Federal de Goiás
Resumo
This work shows the green coffee oil coacervation processes, as core material, in two
different systems: whey protein / gum arabic and soy protein / gum arabic, as biopolymer
wall. The biopolymers concentration were fixed in 4% (weight / weight) of the emulsion, and
the proportion between then was respectively 2:1 and 1,4:1. Different emulsions were made,
each one with a different green coffee oil concentration (0%, 10%, 17.5% and 25%) compared
with wall materials. From these emulsions with adjusted pH, the system presented phase
separation (coacervation). The following system characteristics were studied: maximum
interation pHs, emulsions rheological behavior, emulsions sizes, physico-chemical
characterization of the phases (coacervate and supernadant), process mass balance, coacervate
rheology, microparticles morphology after lyophilization, the powder density, the powder
stability and the microencapsulation process efficiency. The results confirmed that there is an
optimum range of particle formation, depending on pH. The emulsions presented typical
Newtonian fluid behavior and the viscosity increased with incresing the oil concentration.
That behavior does not depend on wall materials. It was also observed that wet coacervates
were better fitted to Power Law, presenting pseudoplastic behavior. Concentrate soy protein /
gum arabic showed thixotropy. The emulsion gout showed an surface average diameter
between 2,24 µm e 14,42µm. The microparticles exhibited slightly spherical, rough surface
and pores, probably influenced by drying process. The process efficiency showed no
dependence on the oil concentration at studied systems. The adsorption isotherms (at 30°C) of
the obtained powders were best fitted to the GAB model and the e moisture content of
monolayer (xm) for this model were between 2.5% to 5.1% for CPSL and GA microparticles
and between 5.1% and 6.1% for IPS and GA
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MAGGIOLI, M. F. Retenção de óleo de café verde em complexos coacervados de proteínas concentradas do soro de leite ou soja e goma arábica. 2014. 91 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos) - Universidade Federal de Goiás, Goiânia, 2014.