SILVA, A. C. C.; http://lattes.cnpq.br/0134004595056295; SILVA, Ana Celia Cordeiro da.
Resumo:
Urea is one of the alternatives in cost reduction and because of its applicability
in food. The objective was to obtain microencapsulated systems with natural lipid
encapsulants containing urea with and without sulfur by the
emulsification/lyophilization technique, including four systems at a fixed ratio of 2:1
(Wax:Urea), namely: CAUS (Beeswax: urea: sulfur), CCUS (Wax of carnauba: urea:
sulfur), CCA (Beeswax: urea), CCU (Carnauba wax: urea). For systems enriched with
sulfur (magnesium sulfate heptahydrate), whose nitrogen and sulfur source ratio was
10:1, respectively. All microencapsulated systems were characterized regarding
microencapsulation yield (RM), retained urea content (loading capacity),
microencapsulation efficiency (EM) and thermogravimetry (TG), differential scanning
calorimetry (DSC) techniques and water activity (Aw). The microparticles in situ were
also histories against the ruminal and blood parameters, using two rumen fistulated
sheep, male Santa Inês breed with an average weight of 48.9 ± 5.2 kg and aged 2 years.
The formulations CAUS, CCUS, CAU, and CCU microencapsulation dissipation
97.15±9.28, 75.65±2.44, 98.29±2.15, 94.46%±1.8 respectively. The DSC and TG
curves showed that the presence of the S source decreases the effectiveness of urea
protection, the beeswax lipid microparticles as an encapsulant have greater thermal
stability, which is related to a better protection of the core in relation to temperature,
enabling the intended gradual release. The of the microparticles for the last incubation
time (48 h) was investigated by scanning electron microscopy (SEM) in which the
presence of the sulfur source decreased, even if slightly, the thermal stability of the
microparticles for both cerids studied. The CCU system established the highest mean
with pH among the neutrality reference values of 6.45, this system favored the
significant increase in the population density of rumen protozoa expressing its
significance of the highest mean of 14.97 protozoa (106/mL). The CAUS formulation
promoted greater protozoan density and motility among the categories, presenting the
respective values of 6.0, 6.88 and 7.5 min. The microstructure for the last incubation
time (48 h) was investigated by scanning electron microscopy (SEM), suggesting the occurrence of biodegradation, which increases with the inclusion of the sulfur source
for both cerids studied.