Resumo (PT):
Abstract (EN):
Vitamin B12 is a very important micronutrient essential for health (due to its functions) supplied by the diet,
mostly, from animal sources. Its deficiency may cause critical health problems, whereby it is important to incorporate this vitamin in food supplements and additives. On the other hand, vitamin B12 is a sensitive compound
and can be easily degrade during food process and storage. Through microencapsulation it is possible to overtake
some of these limitations and improve its application in food industry. The aim of this work was to produce
microparticles with vitamin B12 (1, 2, 3, 4 and 5% (w/w)) and to study its release namely in simulated gastric conditions (SGF). Modified chitosan was chosen as encapsulating agent, considering its biocompatibility and good
solubility in water. The microparticles were prepared by a spray-drying technique and then characterized in
terms of morphology (Scanning Electron Microscopy - SEM) and particle size (Laser Granulometry Analysis).
An UV spectrophotometric method was validated, to evaluate the vitamin release and its stability. The average
diameter of the particles varies with vitamin concentration, ranging from 3 to 8 μm, considering the differential
volume distribution, and from 0.1 to 0.9 μm considering the differential number distribution. The product yield of
the spray-drying process was around 57% for the microparticles with vitamin. The SEM images show microparticles with a regular round shape and a smooth surface. The release time increases with increasing of pH, and
decreases with decreasing temperature. The Weibull kinetic model fits very well the experimental results
obtained in SGF at 37 °C. Microparticles stability was evaluated after 3 and 6 months and a small decrease in
the amount of vitamin released was observed. Vitamin losses are b10% for 3 months and b20% for six months
storage. So, microparticles of vitamin B12 with a good stability can be produced by spray-drying using modified
chitosan.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
8