The diploma thesis deals with the Influence of the Enzyme L-asparagine and the Inorganic salts (NaCl, CaCl2, NaHCO3 and NH4HCO3) on the elimination of the acrylamide in food-stuffs and a simulated model cereal matrix. The acrylamide belongs to the probable carcinogenic compounds which is incipient in the course of thermal processing of food, which are rich in the reducing sugars and amino acids as L-asparagine. Because of L-asparagine is the natural component of cereals and simultaneously is dominant antecedent incipient acrylamide, the way of the elimination by enzyme L-asparaginase (or the combination of L-asparaginase and salt) leads to the reduced level of acrylamide in a final product. The L- asparagine and salts were used on food-stuffs and a simulated model cereal matrix. It was found that individual used substances (except for NH4HCO3) cause the reduction of acrylamide production even about 90 % without change in the sensory properties of final product.

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A commercial valve-assisted micromixer, manufactured by Ehrfeld (Germany), was tested for its use to precipitate L-asparagine from an aqueous solution using isopropanol as antisolvent. In a first part the mixing quality provided by the micromixer was studied by means of a competitive/parallel set of reactions following the approach of Baldyga, Bourne and Walker, Canadian J. Chem. Eng. 76 (1998) 641-649. Different experiments have been implemented and interpreted considering the average of Reynolds number of the inlet streams. Results show a good mixing quality that is comparable, in terms of absolute values of conversion, with other works present in literature. The precipitation experiments that followed revealed the limitation of the micromixer. The system was instable and particles adhesion occurred inside the mixing chamber. Improvements have been realized by changing the spring tension of the valve and introducing a commercial surfactant TRITON X-100.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work we present the results of L-asparagine H2O crystal growth and the study of their optical properties, linear and nonlinear, of crystal as grown and after being submitted to high doses of X-ray. Crystals were grown in aqueous solution by the method of slow evaporation of the solvent. Measurements optical absorption, Raman, thermal analysis and efficiency of second harmonic generation were carried out. The results demonstrate the good optical quality of the crystals for use in optical devices, comparable to that of KDP (KH2PO4). . / Neste trabalho apresentamos os resultados do crescimento de cristais de L-Asparagina-H2O e do estudo de suas propriedades ópticas, lineares e não lineares, do cristal como é crescido e após ser submetido a altas doses de raios-X. Os cristais foram crescidos em solução aquosa pelo método de evaporação lenta do solvente. Foram realizadas medidas de absorção óptica, Raman, análise térmica e eficiências de geração de segundo harmônico. Os resultados demonstram as boas qualidades ópticas dos cristais para aplicação em dispositivos ópticos, comparáveis ao do KDP (KH2PO4).