Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1921. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed May 29, 2009). Includes bibliographical references (p. 13).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1909. / Roy H. DeWaters determined to be Roy Hayward DeWaters and year degree was granted determined from "Forty-First Annual Catalogue. School of Mines and Metallurgy, University of Missouri". The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed )

Orientador: Delia Rodriguez-Amaya / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T22:37:14Z (GMT). No. of bitstreams: 1 Oliveira_GiovannaPisanelliRodriguesde_M.pdf: 717154 bytes, checksum: 6bd8167ae6c34a616ee50857b97e1f31 (MD5) Previous issue date: 2006 / Resumo: A determinação de luteína e zeaxantina, carotenóides relacionados à proteção contra a catarata e a degeneração macular associada a idade, pode ajudar na proteção da população da terceira idade contra estas doenças. O milho é uma das únicas fontes de ambos carotenóides. Dentre os produtos analisados (milho in natura, milho cozido, milho enlatado, polentas frita e cozida, curau e pamonha) por cromatografia líquida de alta eficiência, o milho enlatado apresentou, em geral, os maiores teores de carotenóides (0,56 a 4,12 mg/g de luteína, 7,10 a 22,90 mg/g de zeaxantina, 0,60 a 4,90 mg/g de b-criptoxantina e 0,13 a 3,45 mg/g de b-caroteno). O milho in natura e o milho cozido, diferentemente dos outros produtos analisados, não apresentaram como carotenóide majoritário a zeaxantina e sim a luteína (3,37 a 5,29 _g/g e 2,79 a 5,47 para milho in natura e cozido, respectivamente). Os teores de carotenóides das polentas frita e cozida, curau e pamonha foram muito baixos. As farinhas e cereais matinais a base de milho, também analisados, apresentaram, em geral, a zeaxantina como carotenóide majoritário, seguido pela luteína. Os pró-vitamínicos, b-caroteno e b-criptoxantina apareceram em pequenas concentrações. Os teores de luteína e zeaxantina (mg/g) variaram, respectivamente, de 1,52 a 6,54 e 2,93 a 15,01 para farinhas derivadas de milho e 1,83 a 4,88 e 7,54 a 16,24 para cereais matinais. Houve variação marcante entre marcas do mesmo produto, mas pequenas variações entre lotes da mesma marca / Abstract: The determination of luteína and zeaxantina, carotenóides related to the protection against the cataract and the degeneration to stain associated the age, can help in the protection of the population of the third age against these illnesses. The maize is one of the only sources of both carotenóides. Amongst the products analyzed (maize in natura, cooked maize, tinned maize, polentas fries and cozida, curau and pamonha) for liquid chromatography of high efficiency, the tinned maize presented, in general, the biggest texts of carotenóides (0,56 the 4,12 mg/g of luteína, 7,10 the 22,90 mg/g of zeaxantina, 0,60 the 4,90 mg/g of the 3,45 b-criptoxantina and 0,13 mg/g of b-carotene). The maize in natura and the cooked maize, differently of the other analyzed products, had not presented as carotenóide majority the zeaxantina and yes the luteína (3,37 the 5,29 _ g/g and 2,79 the 5,47 for maize in natura and stew, respectively). The texts of carotenóides of the polentas fry and cozida, curau and pamonha had been very low. The matinal flours and cereals the maize base, also analyzed, had presented, in general, the majority zeaxantina as carotenóide, followed for the luteína. The pro-vitaminic ones, b-carotene and b-criptoxantina had appeared in small concentrations. The texts of luteína and zeaxantina (mg/g) had varied, respectively, of 1,52 6,54 and 2,93 the 15.01 for flours derived from maize and 1,83 4,88 and 7,54 the 16,24 for matinal cereals. It had marcante variation between marks of the same product, but small variations between lots of the same mark / Mestrado / Mestre em Ciência de Alimentos

Orientador: Lucia Maria Valente Soares / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T17:17:15Z (GMT). No. of bitstreams: 1 Milanez_ThaisValeria_D.pdf: 2218554 bytes, checksum: 46e6ca6030ebca6708085a2033758933 (MD5) Previous issue date: 2003 / Resumo: Um bom número de espécies de fungos pode, sob condições especiais, produzir metabólitos secundários tóxicos conhecidos como micotoxinas. Cerca de 20 grupos de toxinas são conhecidos hoje, porém, algumas têm recebido atenção especial devido à sua toxicidade e ampla ocorrência natural: aflatoxinas, zearalenona, ocratoxina A, fumonisinas e tricotecenos. Os tricotecenos constituem um grupo de cerca de mais de uma centena de compostos caracterizados pela presença do sistema 12,13-epoxi-tricotec-9-eno em suas estruturas. A maior parte dos tricotecenos conhecidos foi isolada apenas em laboratório, porém, alguns deles foram obtidos e caracterizados como contaminantes naturais. Dentre estes podem ser citados o desoxinivalenol (DON), o nivalenol (NIV), a toxina T-2 (T2), o diacetoxiscirpenol (DAS) e menos freqüentemente os derivados 3-acetil-desoxinivalenol (3-Ac-DON) e 15-acetildesoxinivalenol (15-Ac-DON), a fusarenona-X (FX) e a toxina HT-2 (HT2). Entre todos, o DON é o de maior ocorrência em alimentos e rações animais, porém é também o menos tóxico. Apesar do milho (Zea Mays) ser um dos substratos mais susceptíveis a este tipo de contaminação, há poucos dados sobre o milho brasileiro. Brasil é o terceiro colocado quanto à produção mundial de milho, colhendo ao redor de 30 milhões de toneladas por ano e, portanto, um cereal com grande impacto na economia brasileira. Estes fatos apontam a necessidade de avaliar a extensão e o tipo de contaminação de tricotecenos em milho nacional. Por outro lado, a similaridade das estruturas químicas dos tricotecenos exige o uso de cromatografia com alto poder de resolução para sua separação como é como é o caso da cromatografia à gás. As diferentes toxicidades para os diversos membros do grupo requer, por sua vez, que a identidade de cada toxina seja confirmada por um sistema de alta confiabilidade como a espectrometria de massas. o presente trabalho visou avaliar a incidência de tricotecenos em milho plantado no estado de São Paulo e em produtos de milho comercializados na cidade de São Paulo. Dentre os tricotecenos, DON e NIV foram escolhidos devido a maior freqüência com que são encontrados em todo o mundo. As toxinas DAS, HT2 e T2 foram incluídas devido às suas maiores toxicidades e ocorrência natural comprovada em alimentos e rações. Para alcançar os objetivos descritos foi inicialmente avaliado método para determinação simultânea destes 5 tricotecenos por cromatografia à gás associada à espectrometria de massas. O método analítico após otimização e avaliação apresentou limites de detecção variando de 20 a 60 ng/g para DON, de 10 a 40 ng/g para NIV, de 20 a 120 nglg para DAS, de 20 a 50 ng/g para HT2 e de 20 a 100 ng/g para T2, de acordo com a as matrizes testadas (milho em grão, milho verde em lata, farinha de milho, canjica, fubá e flocos de milho). Da mesma forma, as recuperações variaram de 83 a 113% para DON, de 84 a 115% para NIV, de 69 a 123% para DAS, de 82 a 155% para HT2 e de 71 a 96% para T2. Foram analisadas 80 amostras de milho produzido em duas cooperativas do estado de São Paulo, tendo sido encontradas 11 amostras contendo NIV e uma com DON em nível de traços. Além disso, cinco amostras apresentaram NIV em níveis variando de 51 a 106 ng/g e uma delas co-contaminada com 71 ng/g de DON. Foram também analisadas 78 amostras de produtos de milho comercializados na cidade de São Paulo, sendo que uma delas, farinha de milho, apresentou traços de DON e NIV e outra, quirera, apresentou 555 ng/g e 767 ng/g de toxinas T2 e HT2, respectivamente. Os resultados obtidos nos levantamentos realizados nos anos de 2000 a 2002, mostram baixa ocorrência de tricotecenos, não havendo risco para a população no consumo destes produtos. Devido à sazonal idade da contaminação por micotoxinas em alimentos, conclusões mais amplas só serão possíveis após vários anos de observação da presença dessas toxinas em milho plantado no estado de São Paulo e produtos de milho comercializados na cidade de São Paulo / Abstract: A great number of the fungal species, under specific conditions, can produce toxic secondary metabolites known as mycotoxins. About 20 groups of such toxins are known today but some have received special attention due to their toxicity and widespread natural occurrence: aflatoxins, zearalenone, ochratoxin A, fumonisins and trichothecenes. The trichothecenes constitute a group of more than a hundred compounds characterized by the presence of the system 12,13-epoxy-trichotec-9-en in their structures. However, most of the known trichothecenes have been isolated only in laboratory conditions. Just a few have been isolated and characterized as natural contaminants. Among them, deoxynivalenol (DON), nivalenol (NIV), toxin T-2 (T2) , diacetoxyscirpenol (DAS) and less frequently the derivatives 3-acetyldeoxynivalenol (3-Ac-DON), 15-acetyl-deoxynivalenol (15-Ac-DON), fusarenone X (FX) and the toxin HT-2 (HT2). DON is the trichothecene most frequently found in foods and feeds and it's also the less toxic of this family. Despite the fact that com is one of the substrates more susceptible to this type of contamination, there is little information on the occurrence of trichothecenes in Brazilian com. Brazil ranks third in world production of com, harvesting about 30 million tons annualy, and com is a grain with great impact in Brazilian economy. These facts point to the need to evaluate the extension and the type of trichothecene contamination in national corn. On the other hand, the similarity of the trichothecene chemical structures requires the use of a high resolution gas chromatographic method for their separation, The differing toxicities for the members of this group of toxins requires, by their turn, that the identity of each toxin be confirmed by a system capable of great degree of reliability such as mass spectrometry. The present work aimed at evaluating the occurrence of trichothecenes in com p/anted in the State of São Pau/o and in com products commercialized in the city of São Paulo. DON and NIV were chosen for this investigation due to their worldwide occurrence. DAS, HT2 and T2 were inc/uded due to their high toxicity and their natural occurrence in foods and feeds. In order to reach the objectives of the present work, a gas chromatography/ mass spectrometry method for simultaneous determination of these tive trichothecenes was optimized and evaluated. Afier optimization the method presented detection limits ranging from 20 to 60 ng/g for DON, from 10 to 40 ng/g for NIV, 20 to 120 ng/g for DAS, 20 to 50 for HT2 and from 20 to 100 ng/g for T2, varying according to the tested matrices (dried com, canned sweet com, com grits, com flour, hominy sweet meal, com meal and com flakes). Similarly, the recoveries ranged from 83 to 113% for DON, 84 to 115% for N/V, 69 to 123% for DAS, 82 to 155% for HT2 and 71 to 96% for T2. A survey was conducted in samp/es of com grown in São Paulo State and also in com-based products commercia/ized in the city of São Paulo. Eighty samples of com from two cooperatives located in the State of São Paulo were analysed. E/even samples presented traces of N/V and another sample had traces of DON. Besides that, tive samples showed levels of N/V ranging trom 51 to 106 ng/g and one of them was co-contaminated with 71 ng/g of DON. Seventy-eight samp/es of com-based products commercialized in Sao Paulo city were analyzed. Among these samples, on/y one sample of com flour, presented DON and N/V. Another sample of com grits , had the toxins T2 an HT2 at the leve/s of 555ng/g and 767 ng/g, respectively. The resu/ts of the two surveys during the years 2000 to 2002, indicated a low occurrence of trichothecenes, and as a consequence a low risk for the consumers. Due to the well known variability in mycotoxins contamination of foods from year to year, only after several years of surveyng corn planted in the State of São Paulo and com products commercialized in the city of São Paulo, it will be possible to have a complete picture of the contamination of trichothecenes in com and com products / Doutorado / Doutor em Ciência de Alimentos

Please read the abstract in the section, 00front of theis document / Dissertation (MSc (Agric) Food Science and Technology)--University of Pretoria, 2008. / Food Science / MSc / Unrestricted

submitted in fulfilment of the academic requirements for the degree of Master of Applied Science in Food Science and Technology, Durban University of Technology, 2015. / Vitamin A deficiency (VAD) is a major health problem in sub-Saharan Africa where maize is a staple food. Amahewu, a fermented non-alcoholic,maize-based beverage is a popular drink in southern Africa.The aim of this study is to produce a provitamin A enriched and acceptable amahewu, using provitamin A biofortified maize which can be used to alleviate VAD. The optimal processing parameters for the production of amahewu using provitamin A-biofortified maize were determined. Amahewu samples were prepared with reference to a traditional method by boiling a mixture of maize meal and water (rato:1:7) at 90ᴼC, with occasional stirring, for 15 minutes. The resulting porridge was left to cool to approximately 40ᴼC, before inoculation and fermentation at 37oC. Processing parameters investigated were inoculum types (wheat bran (WB), maize malt (MM) and Lactobacillus mixed starter culture) and inoculum concentration (0.5,1 and 2% (w/w)) and varieties of provitamin A maize (PVAH 62 and PVAH 19). Wheat flour (at 2%) was used as reference inoculum to conform to the traditional practice. White maize amahewu samples processed in the same way as those of provitamin A-biofortified maize were used as references. Provitamin A amahewu samples were produced using the optimized processing parameters and then analysed for nutrient composition, including carotenoids, protein, ash, amino acids, mineral profile and invitro protein digestibility. The consumer acceptability of amahewu samples was evaluated using regular consumers of amahewu (n= 54), who rated the acceptability of the samples on a 9-point hedonic scale (1:disliked extremely, 9:liked extremely). The storage stability of the provitamin A biofortified amahewu samples was assessed by subjecting the samples to different storage conditions: 4ᴼC, 25ᴼC and 37ᴼC. The microbiological quality of the stored samples was monitored by taking samples every day for a period of five days to analyse for the presence of aerobic and anaerobic bacterial spore formers, E.coli and moulds. The provitamin A maize variety did not influence pH and Total titratable acidity (TTA) of amahewu samples during fermentation. As expected, there was a substantial drop in pH with fermentation time. After 24 hours, all the samples of amahewu, including those made with white maize, prepared using malted maize and wheat bran inocula reached a pH of 3.3-3.8 and TTA of 0.3-0.6, which were within acceptable range for amahewu. The addition of a starter culture substantially reduced fermentation time, from 24 to six hours. The inoculum of WB and MM, respectively, at a concentration of 0.5%, with or without starter culture (5%), were found to be suitable for the production of amahewu using provitamin A biofortified maize. The total provitamin A content of amahewu samples, produced using optimised parameters (i.e one variety of provitamin A biofortified maize, 0.5% MM, WB with or without starter culture), ranged from 3.3-3.8 μg/g (DW). The percentage retention of total provitamin A ranged from 79%- 90% (DW). The lowest percentage retention was observed in products fermented with the addition of starter culture. The gross energy of the amahewu samples was approx. 20 MJ/kg. There was a slight increase in the lysine content of amahewu after fermentation. The protein digestibility (approx. 91%) of amahewu samples was slightly higher than that of raw provitamin A maize (86%). Amahewu processed using starter cultures had a slightly higher iron content than those processed without a starter culture. Consumer acceptability data showed that amahewu samples made with provitamin A biofortified maize were slightly more acceptable (average rating for overall acceptability was 7.0 ± 1.2), compared to those made with white maize (average rating for overall acceptability was 6.4 ± 0.8). Principal component analysis (PCA) of Amahewu sensory data showed that 71% of variation was due to maize types and 18% of variation may be due to the inoculum used during fermentation. The use of a starter culture improves the taste and aroma acceptability of amahewu. Segmentation of consumers based on overall linking for amahewu revealed three clusters, named A, B and C. Cluster A consisted of most consumers (43%), who liked amahewu moderately. About 60% of these consumers were females. Cluster B consisted of most of the consumers (31%) who were undecided about their liking for the product. Approximately 52% of the consumers in this cluster were female. Cluster C consisted of consumers (26%) who liked amahewu very much. Sixty-four percent (64%) of these consumers were female. It appeared that gender may have some influence on overall liking for amahewu, as cluster B, consisting of undecided consumers, had more male consumers compared to clusters A and C. Age did not seem to be significantly associated with the liking of amahewu. Provitamin A biofortified amahewu samples stored under refrigerated conditions (4ᴼC) had better microbiological quality compared to those stored at 25ᴼC and 37ᴼC. Refrigeration effectively maintains the microbiological quality of amahewu for about three of days. Provitamin A biofortified maize can be used to produce β-carotene enriched amahewu that is acceptable to consumers following the processing method that is traditionally employed for white amahewu at both domestic and commercial level. Provitamin A biofortified amahewu has the potential to make a significant contribution towards alleviating VAD among rural communities, who are the most vulnerable to VAD.

South Africa is facing numerous challenges that pertain to increasing water deficit and pollution of water resources. Only 40 out of 821 wastewater treatment works in South Africa achieved Green Drop certifications in the 2010 Green Drop assessments (DWA, 2011). This is not only threatening net water availability but also human health. South African water sources are comprised of 77 % surface water, 14 % return flows and 9 % groundwater (van Vuuren, 2009). This study was therefore intended to explore the quality, quantity and treatability of corn wet milling effluent resulting from Tongaat Hulett Starch Pty Ltd (THS) operations. THS is a major producer of corn derived starch and glucose in Africa. Amongst its three corn wet milling plants in Gauteng (Kliprivier, Germiston and Meyerton) and one in Western Cape (Bellville), 600000 tonnes of maize were processed in the 2011/2012 financial year. The objective of the study was to establish the wastewater footprint of the corn wet milling process. To achieve this, qualitative and quantitative characterisation studies were completed on effluents generated from the Germiston and Meyerton corn wet milling plants, respectively. This characterisation study was focused on volumetric and organic load analyses of the various sections of the corn wet milling process. A full scale anaerobic digestion treatability study of the Meyerton plant effluent was also conducted. The study results indicated that the combined effluent discharged to the Municipal sewer averaged between 2.9 and 3.1 m3/tonne of corn processed. The effluent generated resulted in an average chemical oxygen demand (COD) concentrations of between 6211 and 7790 mg/L, with suspended solid concentrations of between 635 and 899 mg/L. From the full scale anaerobic treatability study, a minimum of 87 % COD removal at organic volumetric loading rates (OLR) of between 0.3 and 3.9 kg COD/m3.d was achieved. It was concluded that corn wet milling effluent can be categorised as high strength in terms of COD concentrations. This type of effluent proved to be amenable to anaerobic digestion treatment. Anaerobic pretreatment of corn wet milling effluent can proportionately reduce pollution loading into the receiving municipal conventional wastewater treatment systems. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2013.

Amidos nativos apresentam algumas desvantagens tecnológicas que impulsionam pesquisas voltadas à modificação, visando melhorar as propriedades físico-químicas e promover propriedades funcionais específicas. Modificações como dextrinização e esterificação estão entre as mais utilizadas, porém, apesar dos avanços recentes na área de amidos modificados, ainda há pouca informação sobre as propriedades de dextrinas esterificadas. Assim, o presente estudo teve como objetivos principais a obtenção e caracterização de dextrinas esterificadas com ácido málico a partir dos amidos de mandioca e milho. A modificação dos amidos foi realizada com ácido málico (2,5; 5,0; 7,5 % m/m) durante o processamento térmico (150 °C/ 4 horas) com baixa umidade (≤ 3 %). Para avaliar o efeito de um catalisador ácido, foram realizados ensaios com a adição de HCl (0,05 % m/m), sob as mesmas condições. A termoconversão do amido na presença de ácido málico produz dextrinas esterificadas com baixo grau de substituição (GS) e características aniônicas, além de alta claridade de pasta, solubilidade a frio e baixa viscosidade em elevados teores de sólidos (RVA). A degradação macromolecular reduz o teor de amilose dos amidos após a modificação, assim como a viscosidade intrínseca. Porém, as dextrinas com maior GS apresentaram maior viscosidade intrínseca em solvente DMSO, o que sugere a ocorrência de ligações cruzadas nas dextrinas com maior concentração de ácido málico. Os resultados de dextrose equivalente (DE) também foram dependentes da concentração de ácido málico e os valores variaram de 6,89 a 11,33% nas dextrinas de mandioca e de 8,56 a 12,38 % nas dextrinas de milho. A variação de cor identificou maior tendência a tonalidades amareladas, característica típica de dextrinas termoconvertidas. Na análise de DRX, foi observado que a modificação alterou o padrão de difração das amostras de amido de mandioca e diminuiu a cristalinidade relativa (CR) dos grânulos dos amidos de ambas as fontes botânicas estudadas. A morfologia dos grânulos, analisada por MEV, também foi alterada em ambas as fontes de amido estudadas, assim como suas propriedades térmicas, de maneira que não foi observada transição de fase referente à gelatinização em análise de DSC. / Native starches have some technological disadvantages which stimulate researches for modification, aimed improve physicochemical properties and promote specific functional properties. Modifications as dextrinization and esterification are widely used, however, despite recent advances about modified starches, there is still little information about the properties of esterified dextrins. The aim of this study was to prepare and characterize esterified dextrins from cassava and maize starches using malic acid. The modification of starches was performed by heating a dried mixture (≤ 3%) of starch and malic acid (2.5; 5.0; 7.5 % w/w). To evaluate the effect of an acid catalyst, tests were prepared with addition of HCl (0.05% w/w) under the same conditions. The starch pyrodextrinization in presence of malic acid produces esterified dextrins with low degree of substitution (DS) and anionic properties, as well as high clarity of paste, cold solubility and low viscosity at high solids contents. The macromolecular degradation decreases the amylose content values after modification, as well as the intrinsic viscosity values. However, the dextrins with high GS showed higher intrinsic viscosity in DMSO, which suggests the occurrence of crosslinking in the dextrins with a higher concentration of malic acid. The results of dextrose equivalent (DE) were dependent of malic acid concentration and values ranged from 6.69 to 11.33% in dextrins from cassava starch, and 8.56 to 12.38% in dextrins from maize starch. Color variations indicated its direct dependence on pyrodextrinization conditions and showed trends to yellow tones, typical feature of pyrodextrin. In X-ray diffraction, was observed that modification changed x-ray pattern in dextrins from cassava starch and decreases the relative crystallinity (RC) of the granules from cassava and maize starches, and its granular morphology (SEM) and thermal properties were affected, it was not observed phase transition related to the gelatinization in DSC analysis.

Amidos nativos apresentam algumas desvantagens tecnológicas que impulsionam pesquisas voltadas à modificação, visando melhorar as propriedades físico-químicas e promover propriedades funcionais específicas. Modificações como dextrinização e esterificação estão entre as mais utilizadas, porém, apesar dos avanços recentes na área de amidos modificados, ainda há pouca informação sobre as propriedades de dextrinas esterificadas. Assim, o presente estudo teve como objetivos principais a obtenção e caracterização de dextrinas esterificadas com ácido málico a partir dos amidos de mandioca e milho. A modificação dos amidos foi realizada com ácido málico (2,5; 5,0; 7,5 % m/m) durante o processamento térmico (150 °C/ 4 horas) com baixa umidade (≤ 3 %). Para avaliar o efeito de um catalisador ácido, foram realizados ensaios com a adição de HCl (0,05 % m/m), sob as mesmas condições. A termoconversão do amido na presença de ácido málico produz dextrinas esterificadas com baixo grau de substituição (GS) e características aniônicas, além de alta claridade de pasta, solubilidade a frio e baixa viscosidade em elevados teores de sólidos (RVA). A degradação macromolecular reduz o teor de amilose dos amidos após a modificação, assim como a viscosidade intrínseca. Porém, as dextrinas com maior GS apresentaram maior viscosidade intrínseca em solvente DMSO, o que sugere a ocorrência de ligações cruzadas nas dextrinas com maior concentração de ácido málico. Os resultados de dextrose equivalente (DE) também foram dependentes da concentração de ácido málico e os valores variaram de 6,89 a 11,33% nas dextrinas de mandioca e de 8,56 a 12,38 % nas dextrinas de milho. A variação de cor identificou maior tendência a tonalidades amareladas, característica típica de dextrinas termoconvertidas. Na análise de DRX, foi observado que a modificação alterou o padrão de difração das amostras de amido de mandioca e diminuiu a cristalinidade relativa (CR) dos grânulos dos amidos de ambas as fontes botânicas estudadas. A morfologia dos grânulos, analisada por MEV, também foi alterada em ambas as fontes de amido estudadas, assim como suas propriedades térmicas, de maneira que não foi observada transição de fase referente à gelatinização em análise de DSC. / Native starches have some technological disadvantages which stimulate researches for modification, aimed improve physicochemical properties and promote specific functional properties. Modifications as dextrinization and esterification are widely used, however, despite recent advances about modified starches, there is still little information about the properties of esterified dextrins. The aim of this study was to prepare and characterize esterified dextrins from cassava and maize starches using malic acid. The modification of starches was performed by heating a dried mixture (≤ 3%) of starch and malic acid (2.5; 5.0; 7.5 % w/w). To evaluate the effect of an acid catalyst, tests were prepared with addition of HCl (0.05% w/w) under the same conditions. The starch pyrodextrinization in presence of malic acid produces esterified dextrins with low degree of substitution (DS) and anionic properties, as well as high clarity of paste, cold solubility and low viscosity at high solids contents. The macromolecular degradation decreases the amylose content values after modification, as well as the intrinsic viscosity values. However, the dextrins with high GS showed higher intrinsic viscosity in DMSO, which suggests the occurrence of crosslinking in the dextrins with a higher concentration of malic acid. The results of dextrose equivalent (DE) were dependent of malic acid concentration and values ranged from 6.69 to 11.33% in dextrins from cassava starch, and 8.56 to 12.38% in dextrins from maize starch. Color variations indicated its direct dependence on pyrodextrinization conditions and showed trends to yellow tones, typical feature of pyrodextrin. In X-ray diffraction, was observed that modification changed x-ray pattern in dextrins from cassava starch and decreases the relative crystallinity (RC) of the granules from cassava and maize starches, and its granular morphology (SEM) and thermal properties were affected, it was not observed phase transition related to the gelatinization in DSC analysis.