Ph.D. (Chemistry) / Please refer to full text to view abstract

Thesis (MTech. degree: Pharmaceutical Sciences.)--Tshwane University of Technology, 2012. / Aims to formulate a soluble tablet containing stevioside for use as a sweetener in beverages and food.

M.Sc. (Chemistry) / The name monatin was given to the sweet compound isolated from the roots of the plant Schlerochiton ilicifolius as a mixture of salts, predominantly the sodium salt. The structure of monatin was previously determined by high- field 1 Hand 13 C n . m. r . spectra and confirmed by single crystal X- ray crystallography. The problem of the absolute stereochemistry of monatin did, however, remain unanswered. Several experiments were carried out which provides additional evidence on the relative and absolute stereochemistry of monatin. An approach to the total synthesis of monatin is described. The first phase of this work involves the development of methods for the synthesis of a key intermediate, 1- methyl 2-amino-5- (3'- indolyl)-4-oxopentanoate, using a coupling reaction. The second phase of the synthesis involves the addition of a carboxylic acid equivalent to the ketone group of the coupled product. The final synthetic product was compared with a natural monatin derivative.

Call number: LD2668 .T4 1978 L43 / Master of Science / Chemical Engineering

This study aimed to investigate the effects of commercially available natural (sugar cane molasses, white sugar and brown sugar) and artificial (Canderel™, Equal™, Natreen™, Sweetex™, Splenda™ and Swheet™) sweeteners on various physiological systems. The artificial sweeteners tested in this study may be categorised into their respective groups based on their primary ingredient. The brands Canderel™ and Equal™ contain aspartame, Natreen™ and Sweetex™ consist of saccharin and Splenda™ and Swheet™ are composed of sucralose. The inclusion of artificial or natural sweeteners in the human diet has been continually debated and their implication in the development of certain diseases has raised concern regarding their safe use. Therefore, it is necessary that these food products be subjected to a battery of tests to determine adverse effects on human health.

This study aimed to investigate the effects of commercially available natural (sugar cane molasses, white sugar and brown sugar) and artificial (Canderel™, Equal™, Natreen™, Sweetex™, Splenda™ and Swheet™) sweeteners on various physiological systems. The artificial sweeteners tested in this study may be categorised into their respective groups based on their primary ingredient. The brands Canderel™ and Equal™ contain aspartame, Natreen™ and Sweetex™ consist of saccharin and Splenda™ and Swheet™ are composed of sucralose. The inclusion of artificial or natural sweeteners in the human diet has been continually debated and their implication in the development of certain diseases has raised concern regarding their safe use. Therefore, it is necessary that these food products be subjected to a battery of tests to determine adverse effects on human health.

Philosophiae Doctor - PhD / This study aimed to investigate the effects of commercially available natural (sugar cane molasses, white sugar and brown sugar) and artificial (Canderel, Equal, Natreen, Sweetex, Splenda and Swheet) sweeteners on various physiological systems. The artificial sweeteners tested in this study may be categorised into their respective groups based on their primary ingredient. The brands Canderel and Equal contain aspartame, Natreen and Sweetex consist of saccharin and Splenda and Swheet are composed of sucralose. The inclusion of artificial or natural sweeteners in the human diet has been continually debated and their implication in the development of certain diseases has raised concern regarding their safe use. Therefore, it is necessary that these food products be subjected to a battery of tests to determine adverse effects on human health. / South Africa

Made available in DSpace on 2017-07-21T18:53:11Z (GMT). No. of bitstreams: 1 Luciana Sutil.pdf: 1255337 bytes, checksum: 2293f0c6daa03660dbb43fead13f4ba9 (MD5) Previous issue date: 2009-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Apple pomace, the main solid residue from the juice or cider processing of the Southern States of Brazil, may be used as raw material for extraction of minerals, organic acid, sugar and dietary fibers as well as for production of alcohol, citric acid and some kind of enzymes and secondary metabolites. This change of such residue into raw material with a high economic value requires its chemical and microbiological stabilization, usually done by dehidration. Such dehydration process of apple pomace from four different varieties (Gala, Fuji, Catarina and Joaquina) were done in an adiabatic equipment following a procedure that comprises heated circulating air at 90°C during six hours and an additional step at 52,5°C until the mass temperature start rising what indicates the end of the drying. The stabilized apple pomace was used to extract sucrose, glucose and fructose, their three main soluble sugars, present in high amount. The procedure to recover this sweetener comprehends aqueous extraction at room temperature, purification by hydroalcoolic despectinization, and deionization by ion exchange chromatography and concentration at vacuum and low temperature. The relative proportion of these sugars were confirmed by enzymatic analysis in each step of the process and by HPLC at the final product, concentrated up to 70oBrix. The sweeteners from the four varieties were characterized instrumentally by NMR, FTIR MID with the data analyzed by multivariate procedure PLS. Aiming to allow the use of this product as a natural sweetener it were further evaluated to know the relative sucrose sweetener power, as well as its characteristics of appearance, flavor and taste evaluated by eight judges using the Quantitative Descriptive Analysis (QDA). The acceptances were determined by affective techniques in a scale of 7. The dried pomace has an average of 8g/100g as equilibrium moisture and after ground and sieved the dried pomace retained at 60 Mesh. The colorimetry CIELAB showed a Luminosity of 67, overcoming 50, the limit of dimness/bright. The step of aqueous extraction of sugars from the dried pomace showed 26g of sugars (100%), the step of hydroalcoolic despectinization 24g of sugars (92,3%), the deionization by ion exchange chromatography 21g of sugars (80,77%) and the step of concentration at vacuum 11,02g of sugars (42,40%), with conservation of relative proportion during all the process. The multivariate analysis (PLS), correlation between the dates from NMR and IR, showed Rval/sac=0,99; Rval/glu=0,98; Rval/fru=0,98. Though the sensory evaluation the relative sucrose sweetener power found to be 1,15, with acceptance of 75,70% and defined as acidity, astringency, apple flavor, yellow color and turbidity by QDA. With single sensory characteristics to the category, beyond the good acceptance, the apple sweetener characterized instrumentally with high correlation and microbiologically stable, is an alternative the use of wastes with many applications. / Considerado como resíduo na agroindústria da maçã, o bagaço constitui-se em matéria prima para a obtenção de componentes nobres, como minerais, ácidos orgânicos, compostos fenólicos, pectinas, açúcares e fibras dietéticas, assim como para a produção de álcool, de ácido cítrico, de vários tipos de enzimas e de metabólitos secundários. Para a transformação deste resíduo em matéria-prima, favorecendo a agregação de valores em produtos de interesse comercial, há necessidade de um processo de estabilização química e microbiológica do bagaço, que pode ser feita por desidratação. O processo de desidratação do bagaço de quatro diferentes variedades (Gala, Fuji, Catarina e Joaquina) foi conduzido em equipamento adiabático com ar aquecido a 90ºC por seis horas (até início da perda de massa), seguido de uma etapa complementar a 52,5ºC, temperatura da massa em secagem, até estabelecimento da umidade de equilíbrio, momento de interrupção do processo. O bagaço estabilizado foi usado para extração de frutose, glucose e sacarose, seus três principais açúcares solúveis, presentes em quantidade expressiva. Os métodos de recuperação destes açúcares compreenderam a extração aquosa à temperatura ambiente, a purificação pela despectinização hidroalcoólica e desionização por cromatografia de troca iônica, a concentração sob vácuo a baixa temperatura. A proporção ternária de frutose, glucose e sacarose foi confirmada por análise enzimática em cada etapa do processo e por HPLC no produto final, de concentração maior que 70°Brix. Os adoçantes obtidos das quatro variedades de maçã foram caracterizados instrumentalmente por RMN, FTIR – MID e analisados por procedimento multivariado PLS. Para permitir seu uso como adoçante natural, o poder edulcorante relativo à sacarose foi determinado, bem como suas características sensoriais quanto à aparência, aroma e sabor, avaliadas por oito julgadores e utilizando a Análise Descritiva Quantitativa (ADQ). A aceitação foi determinada por técnica afetiva em escala de sete pontos. O bagaço desidratado apresentou umidade de equilíbrio de aproximadamente 8g/100g e a maior fração dos grânulos, após moagem e tamisação, passaram no crivo de 60 Mesh. A colorimetria CIELAB indicou uma luminosidade da ordem de 67, ultrapassando o limite, pois, de escuro/claro que se situa no valor 50. A etapa de extração aquosa dos açúcares do bagaço desidratado apresentou 26g de açúcares (100%), a etapa de eliminação do álcool 24g de açúcares (92,30%), a de troca iônica 21g de açúcares (80,77%) e a de concentração final 11,02g de açúcares (42,40%), com preservação da proporção ternária durante todo processo. A análise multivariada (PLS), correlação entre os dados obtidos por RMN, FTIR – MID, indicou Rval/sac=0,99; Rval/glu=0,98;Rval/fru=0,98. Através da análise sensorial o poder edulcorante do adoçante de maçã foi de 1,15 em relação a sacarose, apresentando aceitação de 75,70% e definido por doçura inicial e final, acidez, adstringência, aroma de maçã, cor amarelada e turbidez, segundo a ADQ. Com características sensoriais peculiares à categoria, além de boa aceitação, o adoçante de maçã, caracterizado instrumentalmente com elevada correlação e estável do ponto de vista microbiológico, apresenta-se como alternativa de aproveitamento de resíduos com inúmeras aplicações.

Made available in DSpace on 2014-12-17T15:41:52Z (GMT). No. of bitstreams: 1 RosimereMLF_DISSERT.pdf: 4130045 bytes, checksum: 8bd2b0d06407df9f474aa2e763c256ba (MD5) Previous issue date: 2010-01-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Sweeteners provide a pleasant sensation of sweetness that helps the sensory quality of the human diet, can be divided into natural sweeteners such as fructose, galactose, glucose, lactose and sucrose, and articial sweeteners such as aspartame, cyclamate and saccharin. This work aimed to study the thermal stability of natural and artificial sweeteners in atmospheres of nitrogen and syntetic air using thermogravimetry (TG), derivative thermogravimetry (DTG), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). Among the natural sweeteners analyzed showed higher thermal stability for the lactose and sucrose, which showed initial decomposition temperatures near 220 ? C, taking advantage of the lactose has a higher melting point (213 ? C) compared to sucrose (191 ? C). The lower thermal stability was observed for fructose, it has the lowest melting point (122 ?C) and the lower initial decomposition temperature (170 ?C). Of the artificial sweeteners studied showed higher thermal stability for sodium saccharin, which had the highest melting point (364 ? C) as well as the largest initial decomposition temperature (466 ? C under nitrogen and 435 ? C in air). The lower thermal stability was observed for aspartame, which showed lower initial decomposition temperature (158 ? C under nitrogen and 170 ? C under air). For commercial sweeteners showed higher thermal stability for the sweeteners L and C, which showed initial temperature of thermal decomposition near 220 ? C and melting points near 215 ? C. The lower thermal stability was observed for the sweetener P, which showed initial decomposition temperature at 160 ? C and melting point of 130 ?C. Sweeteners B, D, E, I, J, N and O had low thermal stability, with the initial temperature of decomposition starts near 160 ?C, probably due to the presence of aspartame, even if they have as the main constituent of the lactose, wich is the most stable of natural sweeteners. According to the results we could also realize that all commercial sweeteners are in its composition by at least a natural sweeteners and are always found in large proportions, and lactose is the main constituent of 60% of the total recorded / Os ado?antes proporcionam uma agrad?vel sensa??o de do?ura, que auxiliam na qualidade sensorial da dieta humana, os quais podem ser divididos em ado?antes naturais, como a frutose, galactose, glicose, lactose e sacarose; e artificiais, tais como aspartame, ciclamato e sacarina. Este trabalho teve como objetivo estudar a estabilidade t?rmica destes ado?antes em atmosferas de nitrog?nio e ar sint?tico utilizando-se a Termogravimetria (TG), Termogravimetria Derivada (DTG), An?lise T?rmica Diferencial (DTA) e Calorimetria Explorat?ria Diferencial (DSC). Entre os ado?antes naturais analisados verificou-se uma maior estabilidade t?rmica para a lactose e sacarose, que apresentaram temperaturas iniciais de decomposi??o t?rmica pr?ximas de 220 ?C, tendo a lactose vantagem por possuir um maior ponto de fus?o (213 ?C) em rela??o ? sacarose (191 ?C). A menor estabilidade t?rmica foi observada para a frutose, que apresentou o menor ponto de fus?o (122 ?C), assim como uma menor temperatura inicial de decomposi??o t?rmica (170 ?C). Dos ado?antes artificiais estudados verificou-se uma maior estabilidade t?rmica para a sacarina s?dica, que apresentou o maior ponto de fus?o (364 ?C), assim como a maior temperatura inicial de decomposi??o t?rmica (466 ?C sob nitrog?nio e 435 ?C sob ar). A menor estabilidade t?rmica foi observada para o aspartame, com a menor temperatura inicial de decomposi??o t?rmica (158 ?C sob nitrog?nio e 170 ?C sob ar). Para os ado?antes comerciais observou-se maior estabilidade t?rmica para os ado?antes L e C, os quais apresentaram temperaturas iniciais de decomposi??o t?rmica pr?ximas de 220 ?C e pontos de fus?o pr?ximos de 215 ?C. A menor estabilidade t?rmica foi observada para o ado?ante P, que apresentou temperatura inicial de decomposi??o em 160 ?C e ponto de fus?o em 130 ?C. Os ado?antes B, D, E, I, J, N e O apresentaram baixa estabilidade t?rmica com as temperaturas iniciais de decomposi??o pr?ximas de 160 ?C, provavelmente devido ? presen?a do aspartame, ainda que estes possuam como principal constituinte a lactose, que ? o mais est?vel dos ado?antes naturais. De acordo com os resultados p?de-se perceber tamb?m que todos os ado?antes comerciais possuem em sua composi??o pelo ao menos um ado?ante natural e sempre s?o encontrados em grandes propor??es, sendo a lactose o principal constituinte de 60 % do total analisados