Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 232-250).

Thesis (Ph. D.)--Columbia University, 1920. / Vita. Published also without thesis note. Bibliography: p. 468-486.

Thesis (Ph. D.)--Columbia University, 1920. / Vita. Published also without thesis note. Bibliography: p. 468-486.

Thesis (M.Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 232-250) Also available in print.

Memoria para optar al título de Ingeniera en Alimentos / Los alimentos ricos en carbohidratos y que son sometidos a altas temperaturas para su elaboración, generan compuestos potencialmente tóxicos, como lo es la acrilamida, la cual es estudiada como cancerígeno y genotóxico para humanos (2A), siendo el aminoácido asparagina su mayor precursor. El objetivo de este estudio fue elaborar pan tipo hallulla con adición de asparaginasa para obtener niveles reducidos de acrilamida, conservando sus características sensoriales originales. El contenido de acrilamida se determinó en un Cromatógrafo de Gases -Espectrómetro de Masas (GC-MS), en las muestras de pan por triplicado. Se determinó que el contenido de acrilamida presente en el pan control es 108 μg/kg. Se evaluó un rango de concentración de 20-300 ppm de enzima asparaginasa/ kg de harina, siendo el rango óptimo de 100 y 150 ppm de enzima/ kg de harina, pues se reduce la cantidad de acrilamida entre 80% y más del 99%, respectivamente. Mediante un panel sensorial entrenado se evaluó la calidad sensorial y perfil descriptivo del pan elaborado con enzima asparaginasa (300 y 150 ppm de enzima/ kg de harina) respecto al pan de la formulación control. Los resultados muestran que la calidad sensorial fue calificada como grado 1, sin diferencias significativas (p≤0,05) entre el pan control y el pan elaborado con asparaginasa, para los atributos color, apariencia/forma, aroma, sabor y textura. Resultado similar presentó el perfil descriptivo, pues no hubo diferencias significativas (p≤0,05) entre muestras, para los descriptores color corteza, aroma fermentado, aroma tostado/quemado, dureza al tacto, elasticidad miga, dureza en boca, sabor fermentación/levadura y sabor tostado. La elaboración de pan tipo hallulla con la incorporación de la enzima asparaginasa resultó ser una medida adecuada para mitigar la acrilamida en el pan final, obteniendo una reducción casi completa de acrilamida y conservando las características sensoriales originales del pan / Foods rich in carbohydrates cooked at high temperatures generate potentially toxic compounds such as acrylamide, which is studied as carcinogenic and genotoxic compound to humans (2A) and whose main precursor is the amino acid asparagine. The aim of this study was to develop hallulla bread with added asparaginase in order to reduce the levels of acrylamide after baking while preserving its original sensorial characteristics. Acrylamide content was determined by gas chromatography-mass spectrometry (GC-MS) in the bread samples in triplicate. It was determined that the level of acrylamide present in the control bread was 108 μg/kg. A concentration range of 20-300 ppm of asparaginase enzyme/ kg of flour was evaluated, with the optimum range of 100 to 150 ppm of enzyme/ kg of flour, reducing the amount of acrylamide between 80% and 99%, respectively. A trained panel assessed the sensory quality and descriptive profile of bread made with enzyme asparaginase (300 and 150 ppm enzyme/ kg of flour) and the control bread formulation. The results showed that the sensory quality was rated as grade 1, without significant differences (p ≤ 0,05) between the control bread and bread made with asparaginase for the color, appearance / shape, aroma, flavor and texture attributes. Similar result was obtained with the descriptive profile since there was not significant difference (p ≤ 0,05) between samples for color crust, fermented aroma, roasted / burnt aroma, touch hardness, elasticity crumb, hardness mouth, taste fermentation / yeast and toasted flavor descriptors. The manufacture of hallulla bread with the addition of the enzyme asparaginase proved to be a succesfull method to mitigate acrylamide in the final bread, obtaining almost a complete reduction of acrylamide while maintaining the original sensory characteristics of bread / Fondecyt; Fondef

No abstract.

No description available.

No description available.

Diss. / Includes bibliographical references.

Thesis (Ph.D.(Public Affairs))--University of Pretoria, 2008. / Abstract in English. Includes bibliographical references.