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Preparation, characterization, and evaluation of sorghum flour with increased resistant starch contentVu, Thanh Hien Thi January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Yong-Cheng Shi / Sorghum flour is a gluten-free ingredient and can be used to prepare foods for celiac patients. In addition, sorghum flour is a good source of fiber in the form of resistant starch. The objectives of this research were to develop an effective process to increase resistant starch content of sorghum flour and investigate the effects of sorghum protein matrix on starch digestibility. Samples of white sorghum flour (28.9% amylose content) with different moisture contents (0%, 12.5%, 20%, and 30%) were treated at different temperatures (100, 120, and 140 [degrees]C) for different times (1, 2, and 4 h). Samples after heat treatments were tested for starch digestibility, protein digestibility, differential scanning calorimetry (DSC), size-exclusion chromatography (SEC), and X-ray diffraction. The sample treated with 20% moisture at 100[degrees]C for 4 h had high resistant starch (RS) content (22.1% compared with 5.6% of the native sample) and low protein digestibility (8.4% compared with 68.3% of the native sample). The same heat-moisture treatment on isolated sorghum starch showed no significant change in RS content. DSC showed a very low degree of gelatinization for samples treated at moisture contents 20% and below. X-ray diffraction also suggested minimal change in starch crystallinity after heat treatment at low moisture contents (20% and below). Sorghum protein solubility after heat treatment was reduced, suggesting that protein structure was altered during the heat treatments. In conclusion, heat-moisture treatments were successful in increasing resistant starch content of sorghum flour by altering sorghum protein without gelatinizing the starch to retain starch functionality in food product applications. Sorghum flour with increased resistant starch content after heat treatment was evaluated and compared with normal sorghum flour for starch digestibility using the Integrated Total Dietary Fiber method, and for food applications in tortillas.
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The Effects of Aerosol Drug Delivery on Airway Resistance through Heat-Moisutre ExchangersHart, Matthew Thomas 15 September 2009 (has links)
Introduction: The use of heat moisture exchangers (HMEs) is becoming more popular with many institutions delivering aerosolized medications between the HME and the endotracheal tube of patients being mechanically ventilated. When HMEs become saturated resistance can increase which can cause changes that can lead to patient-ventilator dysnchrony, development of intrinsic PEEP, and weaning difficulty. The purpose of this study was to determine the effects of aerosol drug delivery on resistance through heat-moisture exchangers. Method: An in-vitro model to simulate exhaled heat and humidity from a patient’s lungs was developed by connecting the test lung to a cascade humidifier that was placed between the endotracheal tube and the test lung. Temperature (37 ºC) and relative humidity (100%) were held constant through all test runs. Ventilator settings used for the study were as follows: Tidal volume 500 mL, frequency 15/min, PEF 60 L/min, PEEP 5 cmH2O, bias flow 2 L/min and I:E ratio 1:3.The pressurized metered-dose inhaler (pMDI; ProAir HFA) with a minispacer (Thayer Medical), hand-held nebulizer (HHN; Salter Labs) and placebo (No aerosol generator or medication) were compared. Albuterol sulfate (2.5 mg/3 ml) was administered through continuous HHN and six puffs of albuterol were given from a pMDI equaling one treatment. Neither medication nor aerosol device was used with the placebo group in order to determine the effect of HME on airway resistance during mechanical ventilation. Six aerosolized treatments were given to simulate a patient receiving albuterol every four hours over a twenty-four hour period. While five minutes was allowed between treatments, airway resistance was measured via the ventilator before and after the administration of the placebo, pMDI and HHN, which equaled five-minute intervals. Data Analysis: Descriptive statistics, dependent t-tests, one-way analysis of variance (ANOVA), repeated measures ANOVA and post-hoc multiple comparisons were utilized for the data analysis of this study, using SPSS version 16.0. A p-value<0.05 was considered significant. Results: There is a linear time effect with means of airway resistance increasing overtime not only with the placebo but also with the pMDI and nebulizer. At the end of all treatments, the means of resistance with the placebo, pMDI and nebulizer were 9.31 cmH2O/L/sec, 9.37 cmH2O/L/sec and 11.20 cmH2O/L/sec, respectively. While no significant difference was found between the placebo and the pMDI (p=0.452), the nebulizer significantly increased airway resistance when compared to placebo (p=0.004) and the pMDI (p=0.02). Conclusion: Airway resistance increases with use of the placebo, pMDI, and JN groups. Aerosol generators showed a greater increase in resistance when compared to placebo with the greater increase in resistance by HHN.
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Preparation of resistant starch with heat moisture treatment, acid modification, enzymatic modification, and epoxidation methodsYou, Sangwon January 2018 (has links)
The main objectives of this study were to develop an effective process to produce modified pea starch with enhanced enzyme resistance property (RS) for food applications. The work compares a non-chemical method (heat moisture treatment) versus a chemical method (crosslinking). One type of commercial pea starch (Nutri-Pea) was used exclusively as the raw material in this study. A number of methods were used to characterize the properties of the modified pea starches: water solubility index (WSI), titration (conversion, iodine value), intrinsic viscosity, infrared spectroscopy (FT-IR), Englyst digestion method, total starch content, and rapid visco analysis (RVA).
The effects of heat-moisture treatment on native pea starch and enzyme treated pea starch were examined. The results showed that the produced samples with both native starch and enzyme treated starch exhibited a sharp increase in intrinsic viscosity. Overall, this method was deemed undesirable and not extensively examined past preliminary evaluations.
The main focus of the study was on a citric acid crosslinking reaction, chosen for its food compliancy. A temperature of 120 oC was considered ideal for the reaction. FT-IR confirmed the presence of the citric acid incorporation in the starch samples. To improve the extent of reaction, Butanetetracarboxylic acid (BTCA) was considered as a replacement for citric acid and its treated samples showed higher conversion and lower water solubility index than that of the citric acid treated samples. Sodium propionate (NaP) was also considered in the reaction, this time as a food-grade catalyst and found to have minor benefit in cross-linking. BTCA/NaP treated sample reached the highest conversion of the study (96.8±2.3 %) and the lowest WSI (13.1±2.0 %), which increased the RS fraction of the starch from 18% to 32%. The RVA pasting profiles examined were too low to compare due to the high degree of cross-linking.
Further improvements to RS were sought by debranching the starch before acid crosslinking. A BTCA/NaP treated sample with enzyme treatment showed a low WSI (31.7±2.3 %) yet substantially higher RS fraction (80.81±0.18 %). Similar to the non-debranched acid modified samples, there were no significant RVA pasting results because of the high cross-linking.
Finally, crosslinking with an epoxidized oil was tested to continue looking at food-grade solution yet possible increase the rate of the crosslinking reaction. The results of WSI indicated that this method had little influence on cross-linking, possibly due to the low epoxidation efficiency of vegetable oils, as determined by iodine value. / Thesis / Master of Applied Science (MASc)
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ESTUDO TERMOANALÍTICO, REOLÓGICO E ESTRUTURAL DE AMIDO DE TRIGO MODIFICADO POR UMIDADE E TEMPERATURA CONTROLADAS (HMT)Souza, Juliane Alves de 12 December 2014 (has links)
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Previous issue date: 2014-12-12 / Cereals have an important role in human nutrition. Wheat is one of the most cultivated and consumed cereals in the world being used in the preparation of the enormous diversity of products. The wheat flour fortification with iron and folic acid is obligatory in Brazil in according with current legislation. Starch is a reserve polysaccharide of vegetable consisting essentially of amylose and amylopectin. It is a matter abundant and replaceable material being the main source of carbohydrate in diet human. Starches in their native form have limited features for industrial use so it is important modification aiming to acquire improved stability, rheological properties, paste, gel texture, water retention, among others. The chemical modification, still very used, is not considered as safe a one way of modification, so the physical modification is well regarded by food industry. Heat Moisture Treatment (HMT) in starch is considered a natural method and is conducted with a moisture content of 30% and a maximum temperature of 120 ° C. Were studied native wheat and modified starches with presence and absence of folic acid and iron, by HMT at 121 °C for a period of 1 hour. The effects of HMT were studied using the following techniques: thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), x-ray diffraction (DRX), atomic force microscopy (NC-AFM), rapid visco analysis (RVA), the flame atomic absorption spectrometry (FEAA) and reflectance photocolorimetry. From the TG and DTG curves was observed that for the physically treated starches, the values of weight loss for starch in the presence of folic acid iron in the first and third stages decreased and the second increased as increased moisture. The DSC, modified starches, the temperatures at which the event occurred and the enthalpy of gelatinization decreased and the higher the moisture treatment was lower enthalpy. All starches showed bimodal distribution and irregularities in the micro-images of AFM with changes in average diameter and roughness, after physical modification. For all starches DRX peaks did not undergo
pronounced displacement, however there was a decrease in crystallinity after modification. All starches showed high paste temperature and low peak viscosity. Was determined absence iron concentration to starch without folic acid and iron and little change for the presence of starch with these nutrients. With respect to color analysis for all samples studied, there was little variation in color between them, with causing a trend mainly to yellow after modification. / Cereais possuem importante papel na alimentação humana. O trigo é um dos cereais mais cultivados e consumidos no mundo sendo utilizado na elaboração de enorme diversidade de produtos. A fortificação da farinha de trigo com ferro e ácido fólico é obrigatória no Brasil de acordo com a legislação vigente. O amido é um polissacarídeo de reserva vegetal constituído basicamente por amilose e amilopectina. É uma matéria prima abundante e renovável sendo a principal fonte de carboidrato na alimentação humana. Amidos na forma nativa possuem características limitadas para uso industrial por isso torna-se importante sua modificação visando adquirir melhor estabilidade, propriedades reológicas, de pasta, textura de géis, retenção de água entre outros. A modificação química, ainda muito utilizada, não é considerada uma forma tão segura de modificação, por isso a modificação física é bem vista pela indústria alimentícia. A modificação por umidade e temperatura controladas (HMT) em amido é considerada um método natural e é conduzida com teor de umidade de até 30% e temperatura máxima de 121 ºC. Foram estudados amidos trigo nativos e modificados, com presença e ausência de ácido fólico e ferro, por HMT a 121°C por um período de 1 hora. Os efeitos do HMT foram estudados utilizando as seguintes técnicas: termogravimetria e termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC), difração de raios X (DRX), microscopia de força atômica (NC-AFM), análise viscoamilográfica rápida (RVA), espectrometria de absorção atômica com chama (FEAA) e refletância fotocolorimetria. A partir das curvas TG e DTG, observou-se que para os amidos tratados fisicamente, os valores de perda de massa para o amido em presença de ácido fólico e ferro, nas primeiras e terceiras etapas diminuíram e da segunda aumentaram, conforme aumento da umidade. Após a análise de DSC, os amidos modificados, as temperaturas em que ocorreu o evento e o valor da entalpia de gelatinização diminuíram e quanto maior a umidade de tratamento menor foi à entalpia. Os amidos deste estudo apresentaram distribuição bimodal e irregularidades nas microimagens de AFM, com alterações nos diâmetros médios e rugosidade, após a modificação física. Para todos os amidos os picos de DRX não sofreram deslocamento acentuado, porem houve redução da cristalinidade após a modificação. Todos os amidos apresentaram alta temperatura de pasta e baixo pico de viscosidade. Foi determinada ausência de ferro para o amido sem ácido fólico e ferro e pouca alteração para o amido com presença desses nutrientes. Com relação a análise de cor, para todas as amostras estudadas, houve pouca variação de cor entre elas, com tendência ao amarelamento após a modificação.
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Caracterização da dupla modificação física em propriedades termoanalíticas, físico-químicas, estruturais e de pasta da fração amilácea de taro (colocasia esculenta l. schott) orgânicoThomaz, Luísa 09 March 2018 (has links)
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Previous issue date: 2018-03-09 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O taro (Colocasia esculenta L. Schott) é um tubérculo que apresenta até 80 % de material amiláceo em sua composição (base seca), possuindo grânulos pequenos, medindo de 1 μm a 6 μm, enquanto que outras fontes chegam a 100 μm. Amidos nativos podem apresentar limitações tecnológicas e, portanto, modificações físicas, químicas e biológicas são realizadas para ampliar a gama de sua utilização. Neste estudo foi utilizado o amido de taro orgânico, o qual foi modificado por tratamento hidrotérmico (HMT) a partir da variação do teor de umidade (13, 19 e 25 %) e tempo (45, 60 e 75 min), mantendo fixa a temperatura (120 °C). Após esses tratamentos foi aplicado o ultrassom em todas as amostras durante 30 min e amplitude de 60 % (frequência fixa de 20 kHz). Para avaliação e caracterização da amostra nativa e das modificadas foram obtidas imagens por microscopia eletrônica de varredura por efeito de campo (MEV/FEG), as propriedades de pasta por viscoamilografia (RVA), decomposição térmica por termogravimetria (TG), evento de gelatinização por calorimetria exploratória diferencial (DSC) e padrão de cristalinidade por difratometria de raios X (DRX). Houve alteração significativa na cristalinidade relativa, variando de 26,9 % a 32,7 %. O perfil de pasta obteve redução em todos os parâmetros de viscosidade e, no evento de gelatinização, foi observado um aumento de entalpia para todas as condições de HMT, chegando a 14,88 J/g (amostra nativa: 9,45 J/g), além de um alargamento do pico, sugerindo uma maior estabilidade frente ao aquecimento. Devido a esta característica, estudos sugerem aplicação do amido hidrotermicamente tratado em produtos enlatados e congelados. As amostras duplamente modificadas promoveram um encurtamento do evento de gelatinização e redução da entalpia, tendo como menor valor 4,1 J/g; tais resultados ocorreram devido a maior hidratação e menor inchamento do grânulo, o que sugere uma boa dispersibilidade, com possível aplicação em filmes biodegradáveis. / Taro (Colocasia esculenta L. Schott) is a tuber that possesses up to 80% of starchy material in its composition (dry basis) and the size of its granules ranges from 1 μm to 6 μm, while other fonts may have granules up to 100 μm. Native starches can present technological processing limitations, and thus, physical, chemical and biological modifications are performed to improve its application range. In this study, organic taro starch was modified by heat-moisture treatment (HMT), with different moisture levels (13, 19 and 25%) and different time intervals (45, 60 and 75 min). All treatments were performed at 120 °C followed by ultrasound (US) for dual modification. The US was applied for 30 min and 60% of amplitude, at a fixed frequency of 20 kHz, for all samples. The morphology of the native and modified samples where evaluated by scanning electron microscopy (SEM), the pasting properties by viscoamilography (RVA), the gelatinization event by differential scanning calorimeter (DSC) and cristallinity pattern by X-ray difratometry. The major differences where in the relative crystallinity that increased from 26.9% to 32.7%. Additionally, the pasting profile showed a decrease in all parameters. The gelatinization showed an enthalpy increase for all HMT-modified samples, up to 14.88 J/g (native sample: 9.45 J/g). Moreover, a peak broadening was observed, suggesting higher heating stability. Due to this, previous studies suggest that HMT starch can be used in canned and frozen food. The dual modified samples resulted in gelatinization shortening and had a decrease in enthalpy, reaching 4.1 J/g at the minimum. This is due to the higher hydration and lower swelling power of the granule, which indicates a good dispersibility. This gives the taro potential to be used in biodegradable films. Keywords: modified starch, ultrasound, heat-moisture treatment, non-convetional starch.
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Influence of head-moisture treatment on functional, colour and thermal properties of bambara ground-nut starchMathobo, Vhulenda Melinda 20 September 2019 (has links)
MSCFST / Department of Science and Technology / Heat-moisture treatment (HMT) is a physical modification that alters the physicochemical
properties of starch without changing its molecular structure. The objective of the study was to
investigate the influence of HMT on the functional, colour and thermal properties of bambara
groundnut (BG) starch. A central composite rotatable design comprising two independent factors
(temperature and time) was used for the study. The central composite rotatable design was
generated using Design-Expert software version 8.0.1.0. Bambara starch extraction was done by
milling BG into flour (5 Kg), suspension in 15 L, 0.3% sodium hydroxide and centrifugation
followed by washing using distilled water. The starch was then HMT treated in an air oven at 80 -
120 °C for 30 - 90 min under 15 % moisture content (MC) (HMT 15), 25% MC (HMT 25) and 35%
MC (HMT 35). The highest L* and WI values for HMT treated BG starch were observed at HMT
80 °C for 30 min under 15% MC; 100 °C for 60 min (25% MC); and 100 °C for 17.57 min (35%
MC) while the lowest was observed in HMT 100 °C for 102.43 min (15% MC); 120 °C for 90 min
(25% MC); and 120 °C for 90 min (35% MC). In HMT 15-BG starch, the gelatinisation parameters
onset (To), peak (Tp) and concluding temperature (Tc) of the samples decreased as treatment time
and temperature increased whereas gelatinisation enthalpy of BG starch increased with increase
in HMT treatment temperature and time. In HMT 25-BG starch Tp, and gelatinisation enthalpy of
the starch increased with increase in HMT treatment temperature and time. While in HMT 35-BG
starch, To, Tp, Tc and gelatinisation enthalpy of the starches decreased with increase in HMT
treatment temperature and time. In HMT 15-BG starch, the water absorption capacity (WAC),
solubility and swelling power (SP) decreased as treatment time and temperature increased while
oil absorption capacity (OAC) of the starch increased with increase in HMT treatment temperature
and time. In terms of HMT 25-BG starch, the WAC and OAC increased as HMT treatment time
and temperature increased while SP and solubility of the starch decreased with increase in HMT
treatment temperature and time. In HMT 35-BG starch, OAC, solubility and SP decreased as
treatment time and temperature increased while WAC of the starch increased with increase in
HMT treatment temperature and time. The optimum HMT conditions for BG starch were found to
be 80 °C for 30 min (HMT 15), 105.74 °C for 30 min (HMT 25), and 113.16 °C for 30 min (HMT
35). Desirability of the obtained optimum conditions were 0.63 (HMT 15), 0.56 (HMT 25) and 0.64
(HMT 35). Information obtained from scanning electron micrograph indicates oval and round
shape for bambara starch granules, with varying sizes. The range of the granule size width was
4.2 – 4.7 mm and 10 μm for length. The modified starches showed some changes in granule
morphology as they seem to disintegrate with application of HMT. Unmodified and HMT - BG
starches showed characteristic FTIR bands linked with common starches. All the samples
displayed complex vibrations in the region below 1000 cm-1 due to the skeletal vibrations of the
glucose pyranose ring. Statistical analysis on colour, thermal and functional properties of HMT
15-BG, HMT 25-BG and HMT 35-BG starch showed that effects of temperature and treatment
time had no significant (p ≥ 0.05) effect on these properties of HMT-BG starch. However,
treatment time had a significant linear effect (p ≤ 0.05) on swelling power, for HMT 15-BG starch.
In HMT 35-BG starch, WAC was significantly affected by quadratic effect of temperature and time
while solubility was significantly affected by linear effect of time and quadratic effect of
temperature. / NRF
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Modificação física de farinha de araruta para aplicação em massa alimentícia enriquecida com coprodutos agroindustriais / Physical modification of arrowroot flour for application in pasta enriched with agroindustrial coproductsFideles, Marília Cândido 20 December 2019 (has links)
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Previous issue date: 2019-12-20 / Arrowroot is a plant that has abundant starch content and does not present gluten in its
composition, arousing the interest of its use in the production of pasta. However, gluten
substitution must be provided through the use of techniques, such as the arrowroot flour
modification through physical processes. Starch is the highest percentage of arrowroot
composition, so enrichment of the dough is an interesting alternative, and a fortification with
agroindustrial coproducts sources of fiber and protein, such as passion fruit peel and bovine
rumen, may be viable. The objective of this study is to produce flours from agroindustrial
coproducts, to modify by different methods (ultrassonic and heat-moisture treatment) the
starch of arrowroot obtained and determine the viability technological and nutritional aspects
of the use of modified flours and agroindustrial coproducts, source of fiber and protein, in the
production of different types of pasta. The hydration, paste and thermal properties of raw and
modified flours were evaluated. The results of the ultrasound treatments vary with the
temperature between 35.83 and 62% with time between 5 and 15 minutes. For heat-moisture
treatment, the best results were those using the lowest temperature (105 ° C) and shorter
times (15 and 30 minutes). Taking into account the use of modified flours in the production of
pasta, ultrasonic treatments with parameters of intensity of 43.5% and time of 15 min and
heat-moisture treatment with 105 ° C for 15 min were selected. With the technological
techniques of the pasta produced, it was possible to analyze and choose the best parameters
to obtain a pasta with less cooking time, loss of solids, intermediate increase of pasta, and
small values of firmness, angle Hue and C* chromaticity. The proximal composition of the
pasta was satisfactory, being able to be characterized as a food with high protein content and
high fiber content. The pastas with the greatest desirability are a good sensory acceptance.
The results obtained have the possibility to develop and improve the pasta formulated with
raw and modified arrowroot flour and agroindustrial coproducts. / A araruta é uma planta que apresenta conteúdo abundante de amido e não glúten em sua
composição, despertando o interesse da sua utilização na produção de massas alimentícias.
Porém a substituição do glúten deve ser suprida através da utilização de diferentes técnicas,
como, por exemplo, a modificação da farinha por meio de processos físicos. O amido é o
maior percentual da composição da araruta, portanto o enriquecimento da massa é uma
alternativa interessante, e a fortificação com coprodutos agroindustriais fontes de fibra e
proteína, como a casca de maracujá e o rúmen bovino, pode ser viável. O objetivo deste
trabalho é produzir farinhas a partir de coprodutos agroindustriais, modificar por métodos
distintos (ultrassom e tratamento térmico em baixa umidade - TTBU) o amido da farinha de
araruta obtida e determinar a viabilidade tecnológica e nutricional da utilização das farinhas
de araruta modificadas e de coprodutos agroindustriais na produção de diferentes tipos de
massas alimentícias. Foram avaliadas as propriedades de hidratação, de pasta e térmicas das
farinhas cruas e modificadas. Os melhores resultados dos tratamentos com ultrassom são os
com intensidade variando entre 35,83 e 62% com tempo entre 5 e 15 minutos. Já para o
TTBU os melhores resultados da modificação são os que utilizaram menor temperatura
(105°C) e menores tempos (15 e 30 minutos). Levando em consideração o uso das farinhas
modificadas na produção de massas alimentícias, foram selecionados os tratamentos de
ultrassom com parâmetros de intensidade 43,5% e tempo 15 min e TTBU com temperatura
de 105°C por 15 min. Através das análises tecnológicas das massas alimentícias produzidas
foi possível analisar e escolher os melhores parâmetros para se obter uma massa com menor
tempo ótimo de cozimento, perda de sólidos, intermediário aumento de massa, e menores
valores de firmeza, ângulo Hue e cromaticidade C*. A composição proximal das massas foi
satisfatória, podendo ser caracterizada como um alimento com alto teor de proteína e alto
teor de fibra, de acordo com a legislação. As massas com maior desejabilidade apresentaram
uma boa aceitação sensorial. Os resultados encontrados indicam a possibilidade de se
desenvolver e aperfeiçoar massas alimentícias formuladas com farinha de araruta crua e
modificadas e coprodutos agroindustriais.
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Solární zisky v budovách / Solar Gains in BuildingsTenora, Tomáš January 2013 (has links)
Master’s thesis deals with solar gains in buildings. The thesis presents an overview of the theoretical knowledge to solve solar gain. The thesis deals possibilities of measuring the intensity of solar radiation and evaluation of data from the meteorological station in the experimental part. Application of topic is then used for polyfunctional building. This part aims to show possibilities of design of air conditioning systems for the purpose of making indoor microclimate and their subsequent evaluation.
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Organization of Glucan Chains in Starch Granules as Revealed by Hydrothermal TreatmentVamadevan, Varatharajan 07 June 2013 (has links)
Regular starches contain two principal types of glucan polymers: amylopectin and amylose. The structure of amylopectin is characterized according to the unit chain length profile and the nature of the branching pattern, which determine the alignment of glucan chains during biosynthesis. The organization of glucan chains in amylopectin and their impact on the structure of starch are still open to debate. The location of amylose and its exact contribution to the assembly of crystalline lamellae in regular and high-amylose starch granules also remain unknown. The primary focus of this thesis is the organization and flexibility of glucan chains in crystalline lamellae.
The organization and flexibility of glucan chains in native, annealed (ANN), and heat-moisture treated (HMT) normal, waxy, hylon V, hylon VII, and hylon VIII corn starches were examined. This study has shown for the first time that increased amounts of apparent amylose in B-type starches hinder the polymorphic transition (from B to A+B) during HMT. The research has also demonstrated that an iodine-glucan complex transformed the B-type polymorphic pattern of hylon starches into a V-type pattern. The differential scanning calorimetry (DSC) results showed that ANN- and HMT-induced changes were most pronounced in hylon starches. These findings suggest that the glucan tie chains influences the assembly of crystalline lamellae in high-amylose starches.
The relationship between the internal unit chain composition of amylopectin, and the thermal properties and annealing of starches from four different structural types of amylopectin was investigated by DSC. The onset gelatinization temperature (To) correlated negatively with the number of building blocks in clusters (NBbl) and positively with the inter-block chain length (IB-CL). The enthalpy of gelatinization (∆H) correlated positively with the external chain length of amylopectin. Annealing results showed that starches with a short IB-CL were most susceptible to ANN, as evidenced by a greater increase in the To and Tm. The increase in enthalpy was greater in starches with long external chains and IB-CLs. These data suggest that the internal organization of glucan chains in amylopectin determines the alignment of chains within the crystalline lamellae and thereby the thermal properties and annealing of the starch granules.
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