Doctor of Philosophy / Department of Grain Science and Industry / Yong-Cheng Shi / Starch is the most important source of food energy. However, the information about the metabolic quality of starchy foods is scarce. It is well known that native starches with a B-type X-ray diffraction pattern are more resistant to alpha-amylase digestion than those starches with an A-type X-ray pattern, but the underlying mechanism is not well understood. It is not clear whether the enzyme resistance of B-type starch is due to its B-type crystalline structure or the other structural features in starch granules. The objective of this study was to compare the structure and enzyme digestibility of highly pure A- and B-type starch crystals, and understand the roles of crystalline types in starch digestibility. Highly pure A- and B-type starch crystals were prepared from short linear α-glucans (short-chain amylose) generated from completely debranched waxy starches by manipulating the processing conditions such as starch solids concentration, crystallization temperature and chain length. High concentration, high temperature and short chain length favored the formation of the A-type structure, whereas reverse conditions resulted in the B-type polymorph. Digestion results using a mixture of α-amylase and glucoamylase showed that A-type crystals were more resistant to enzyme digestion than B-type crystals. The A-type crystalline product obtained upon debranching 25% waxy maize starch at 50ºC for 24 h gave 16.6% digestion after 3 h, whereas B-type crystals produced by debranching 5% waxy maize starch at 50ºC for 24 h followed by holding at 25ºC for another 24 h had 38.9% digested after 3 h. The A-type crystals had a higher melting temperature than the B-type crystals as determined by differential scanning calorimetry. Annealing increased the peak melting temperature of the B-type crystals, making it similar to that of the A-type crystals, but did not improve the enzyme resistance. The possible reason for these results was due to more condense packing pattern of double helices in A-type crystallites. It seems that the crystalline types are not the key factor that controls the digestibility of native starch granules. The resistance of native starches with B-type X-ray diffraction pattern is probably attributed to the other structural features in starch granules.

A presente proposta teve como objetivo avaliar aspectos anatômicos e físico-químicos em frutos de macieiras (Malus domestica Borkh.), Gala e Galaxy, cultivadas em três diferentes altitudes, buscando correlacioná-las ao distúrbio fisiológico, conhecido por lenticelose (lenticel breakdown), caracterizado pelo escurecimento das lenticelas e ocorrência de depressões de coloração parda ao redor destas estruturas. Os frutos maduros foram colhidos na safra 2008-09, em pomares comerciais localizados em cada uma das três áreas produtoras: Vacaria (RS), Fraiburgo (SC) e São Joaquim (SC), localizadas a 971, 1.048 e 1.353 m de altitude, respectivamente. As avaliações foram realizadas nos frutos maduros recém-colhidos e durante o armazenamento, quando os frutos foram submetidos a duas condições distintas: refrigeração (0ºC e 90% UR) e atmosfera controlada (1,5% O2; 2,5% CO2; 0ºC e 90% UR). Os frutos foram avaliados anatomicamente na colheita e durante o armazenamento quando detectado algum distúrbio fisiológico relacionado às lenticelas. A superfície dos frutos maduros de macieiras Gala e Galaxy, recém-coletados nas três localidades e ao final do armazenamento nas condições estudadas, foram analisadas ao microscópio eletrônico de varredura a fim de comparar a deposição das ceras epicuticulares. Adicionalmente os frutos foram avaliados em intervalos de 30 dias, durante os armazenamentos quanto ao teste de tingimento de lenticelas (número) e aos seguintes atributos de qualidade: cor, firmeza, índice de maturação, teor de sólidos solúveis, acidez titulável e, ou outros distúrbios fisiológicos. Também foi analisada a estrutura anatômica dos frutos de macieiras Gala e Galaxy, coletados em Vacaria (RS), em diferentes fases do desenvolvimento a fim de caracterizar a formação dos diferentes tipos de lenticelas. Não houve diferenças no padrão de formação das lenticelas entre Gala e Galaxy e entre os locais de produção. Nos frutos com o sintoma da lenticelose havia uma depressão na superfície resultante da obliteração de células da epiderme e camadas subepidérmicas, sendo que no parênquima subjacente à depressão havia amplos espaços formados pela lise das células. Nem sempre a área sintomática estava associada à presença da lenticela. Os resultados mostraram que a altitude não interferiu na espessura cuticular nem no padrão de deposição de ceras epicuticulares nos frutos de macieiras Gala e Galaxy. Nos frutos recém-colhidos de Gala e Galaxy foi observada a deposição de ceras na forma de plaquetas paralelas e o mecanismo de rompimento e reparo. Após quatro meses de armazenamento, houve alteração no formato das ceras epicuticulares de plaquetas para aglomerados esféricos ou amorfos nos frutos da Gala e Galaxy provenientes de todas as localidades. As alterações foram mais evidentes na condição de armazenamento em atmosfera controlada. Não houve diferenças significativas entre as duas condições de armazenamento e a manifestação dos sintomas nas macieiras Gala e Galaxy procedentes das três regiões produtoras em relação aos parâmetros físico-químicos analisados. A maior incidência ocorreu em frutos Gala provenientes de São Joaquim (SC) ao final do período de armazenamento. / The aim of this study was to describe anatomical and physico-chemical characteristics of apple fruits (Malus domestica Borkh.) \' Gala \' and \' Galaxy \' grown in three different altitudes, seeking to correlate them to the physiological disorder known as lenticelose (lenticel breakdown), characterized by the darkening of lenticels and the occurrence of brownish depressions around them. Mature fruits were harvested in 2008-09, from commercial orchards located in each of three producing areas: Vacaria (RS), Fraiburgo (SC) and São Joaquim (SC), located at 971, 3.088 and 1.353 m altitude, respectively. The evaluations were realized in the mature, freshly harvested fruits and during the storage, when the fruits were subjected to two distinct conditions: refrigeration (0ºC and 90% HU) and controlled atmosphere (1.5% O2; CO2; 2.5%, 0ºC and 90% HU). The fruits were evaluated anatomically at the harvest moment and during storage, when any physiological disorder related to lenticels was detected. The surface of the mature fruit of apple \'Gala \' and \'Galaxy \' freshly harvested from the three localities and at the end of the storage period in the studied conditions were examined under scanning electron microscope to compare the deposition of epicuticular waxes. Additionally, the fruits were evaluated at every 30 days, during storage, in relation to lenticels dyeing test (number) and to the following qualitative attributes: color, firmness, index of ripening, soluble solids content, titratable acidity and physiological disorders. In order to characterize the formation of different types of lenticels, the anatomical structure of fruits, collected in Vacaria (RS), it was also analyzed in different stages of development. There were no differences in the pattern of formation of lenticels between \'Gala\' and \'Galaxy\' and the producing areas. Fruits with \'lenticel breakdown\' symptoms had a surface depression as a result of the obliteration of the epidermal and sub epidermal cells, and the underlying parenchyma exhibited large spaces formed by cell lyses. The symptomatic area was not always associated to the presence of lenticels. The results showed that the altitude did not affect the cuticular thickness or the pattern of deposition of epicuticular waxes in apple fruits of \'Gala\' and \'Galaxy\'. In freshly harvested fruits it was observed the deposition of wax platelets and the mechanism named Tear and Repair or Rip and Stitch\". After four months of storage, we observed changes in the shape of the waxes from platelets to spherical or amorphous clusters in fruits of \'Gala\' and Galaxy from all producing areas. The changes were most evident in controlled atmosphere storage condition. There were no significant differences between the two storage conditions and the onset of symptoms in fruits from the three producing areas in relation to the physico-chemical parameters. The highest incidence of symptoms occurred in fruit \'Gala\' from São Joaquim (SC) at the end of the storage period.

The replacement of synthetic polymers with renewable content in emulsion polymerization latexes has been a focus of research over the past several decades. Emulsion polymerization is a more sustainable way to produce polymers for films and resins. Starch is a sustainably sourced material that has proven to be extremely useful as a filler, comonomer, and property modifier for polymer latexes. In this thesis, we attempt to incorporate high levels of starch materials into emulsion latex using waxy and dent sourced (cheaper) vinyl-functionalized regenerated starch nanoparticles (RSNPs). When fed as a batch charge, incorporation (by reaction as opposed to blending) of a grade of waxy RSNPs with 3 wt.% polymerizable sugar-based monomer (PSBM) and medium hydrophobicity (S-3-M) into the polymer matrix was 0-10 wt.% for a 15 wt.% RSNP loaded, 40 wt.% solids latex. Semi-batch feeding of the S-3-M RSNPs resulted in stable latex with the highest loadings of 40 and 50 wt.% (40 wt.% solids) with 0-10 wt.% RSNP incorporation into the synthetic particles, while 40 wt.% loading (20 wt.% incorporation) was achieved with a grade of waxy RSNPs with 6 wt.% PSBM and medium hydrophobicity (S-6-M). Strategies were developed to prepare synthetic latexes with high RSNP loadings and moderate incorporation. Dent sourced RSNPs proved difficult to use in emulsion formulations due in part to the higher percentage of water-soluble linear amylose in the nanoparticles. To reduce the chances of coagulation and minimize the viscosity of the final latex it was important to ensure monomer starved conditions, that the only initiator feed occurred at the seed stage of the reaction (to degrade the soluble starch and prevent later stage coagulation), and that a hydrophobic tie-layer was used to assist in removal of soluble starch from the water phase. Although a successful procedure was devised for creating a dent sourced RSNP loaded latex with a viscosity of 250 cp, it was significantly longer than the procedures used with waxy RSNPs (6 h polymerization + 1 h RSNP dispersion). An additional treatment of the RSNP dispersion prior to the polymerization can lower the final latex viscosity to 100 cp. Higher incorporation of vinyl-functionalized RSNPs may be achievable if the covalently bonded PSBM functional groups are resistant to hydrolysis, the amylose and other small MW starches are completely removed from the water phase, and monomers with more appropriate reactivity and hydrophobicity are employed. To this end, maleic and methacrylic anhydride modified RSNPs were prepared and tested in emulsion polymerizations. The maleic anhydride modified RSNPs were successfully loaded into an emulsion latex at 15 wt.% (40 wt.% solids content) resulting in 20-30 wt.% incorporation when utilizing 2-ethylhexyl acrylate as the tie-layer monomer with 2-ethylhexyl acrylate or butyl acrylate/methyl methacrylate/acrylic acid as the shell layer. This work presents the only comprehensive attempt to incorporate RSNPs into synthetic latexes at high loadings and solids with persulfate initiation without the need to severely reduce the RSNP molecular weight. The learning generated provides a framework for continuing research into increasing the incorporation of RSNPs into polymer particles.

A presente proposta teve como objetivo avaliar aspectos anatômicos e físico-químicos em frutos de macieiras (Malus domestica Borkh.), Gala e Galaxy, cultivadas em três diferentes altitudes, buscando correlacioná-las ao distúrbio fisiológico, conhecido por lenticelose (lenticel breakdown), caracterizado pelo escurecimento das lenticelas e ocorrência de depressões de coloração parda ao redor destas estruturas. Os frutos maduros foram colhidos na safra 2008-09, em pomares comerciais localizados em cada uma das três áreas produtoras: Vacaria (RS), Fraiburgo (SC) e São Joaquim (SC), localizadas a 971, 1.048 e 1.353 m de altitude, respectivamente. As avaliações foram realizadas nos frutos maduros recém-colhidos e durante o armazenamento, quando os frutos foram submetidos a duas condições distintas: refrigeração (0ºC e 90% UR) e atmosfera controlada (1,5% O2; 2,5% CO2; 0ºC e 90% UR). Os frutos foram avaliados anatomicamente na colheita e durante o armazenamento quando detectado algum distúrbio fisiológico relacionado às lenticelas. A superfície dos frutos maduros de macieiras Gala e Galaxy, recém-coletados nas três localidades e ao final do armazenamento nas condições estudadas, foram analisadas ao microscópio eletrônico de varredura a fim de comparar a deposição das ceras epicuticulares. Adicionalmente os frutos foram avaliados em intervalos de 30 dias, durante os armazenamentos quanto ao teste de tingimento de lenticelas (número) e aos seguintes atributos de qualidade: cor, firmeza, índice de maturação, teor de sólidos solúveis, acidez titulável e, ou outros distúrbios fisiológicos. Também foi analisada a estrutura anatômica dos frutos de macieiras Gala e Galaxy, coletados em Vacaria (RS), em diferentes fases do desenvolvimento a fim de caracterizar a formação dos diferentes tipos de lenticelas. Não houve diferenças no padrão de formação das lenticelas entre Gala e Galaxy e entre os locais de produção. Nos frutos com o sintoma da lenticelose havia uma depressão na superfície resultante da obliteração de células da epiderme e camadas subepidérmicas, sendo que no parênquima subjacente à depressão havia amplos espaços formados pela lise das células. Nem sempre a área sintomática estava associada à presença da lenticela. Os resultados mostraram que a altitude não interferiu na espessura cuticular nem no padrão de deposição de ceras epicuticulares nos frutos de macieiras Gala e Galaxy. Nos frutos recém-colhidos de Gala e Galaxy foi observada a deposição de ceras na forma de plaquetas paralelas e o mecanismo de rompimento e reparo. Após quatro meses de armazenamento, houve alteração no formato das ceras epicuticulares de plaquetas para aglomerados esféricos ou amorfos nos frutos da Gala e Galaxy provenientes de todas as localidades. As alterações foram mais evidentes na condição de armazenamento em atmosfera controlada. Não houve diferenças significativas entre as duas condições de armazenamento e a manifestação dos sintomas nas macieiras Gala e Galaxy procedentes das três regiões produtoras em relação aos parâmetros físico-químicos analisados. A maior incidência ocorreu em frutos Gala provenientes de São Joaquim (SC) ao final do período de armazenamento. / The aim of this study was to describe anatomical and physico-chemical characteristics of apple fruits (Malus domestica Borkh.) \' Gala \' and \' Galaxy \' grown in three different altitudes, seeking to correlate them to the physiological disorder known as lenticelose (lenticel breakdown), characterized by the darkening of lenticels and the occurrence of brownish depressions around them. Mature fruits were harvested in 2008-09, from commercial orchards located in each of three producing areas: Vacaria (RS), Fraiburgo (SC) and São Joaquim (SC), located at 971, 3.088 and 1.353 m altitude, respectively. The evaluations were realized in the mature, freshly harvested fruits and during the storage, when the fruits were subjected to two distinct conditions: refrigeration (0ºC and 90% HU) and controlled atmosphere (1.5% O2; CO2; 2.5%, 0ºC and 90% HU). The fruits were evaluated anatomically at the harvest moment and during storage, when any physiological disorder related to lenticels was detected. The surface of the mature fruit of apple \'Gala \' and \'Galaxy \' freshly harvested from the three localities and at the end of the storage period in the studied conditions were examined under scanning electron microscope to compare the deposition of epicuticular waxes. Additionally, the fruits were evaluated at every 30 days, during storage, in relation to lenticels dyeing test (number) and to the following qualitative attributes: color, firmness, index of ripening, soluble solids content, titratable acidity and physiological disorders. In order to characterize the formation of different types of lenticels, the anatomical structure of fruits, collected in Vacaria (RS), it was also analyzed in different stages of development. There were no differences in the pattern of formation of lenticels between \'Gala\' and \'Galaxy\' and the producing areas. Fruits with \'lenticel breakdown\' symptoms had a surface depression as a result of the obliteration of the epidermal and sub epidermal cells, and the underlying parenchyma exhibited large spaces formed by cell lyses. The symptomatic area was not always associated to the presence of lenticels. The results showed that the altitude did not affect the cuticular thickness or the pattern of deposition of epicuticular waxes in apple fruits of \'Gala\' and \'Galaxy\'. In freshly harvested fruits it was observed the deposition of wax platelets and the mechanism named Tear and Repair or Rip and Stitch\". After four months of storage, we observed changes in the shape of the waxes from platelets to spherical or amorphous clusters in fruits of \'Gala\' and Galaxy from all producing areas. The changes were most evident in controlled atmosphere storage condition. There were no significant differences between the two storage conditions and the onset of symptoms in fruits from the three producing areas in relation to the physico-chemical parameters. The highest incidence of symptoms occurred in fruit \'Gala\' from São Joaquim (SC) at the end of the storage period.

Orientador: Cláudio Cabello / Banca: Rogério Lopes Vieites / Banca: Simone Damasceno Gomes / Resumo: Este trabalho teve como objetivo o desenvolvimento de uma massa alimentícia produzida a partir de mandioca cozida para utilização em diversos fins culinários. Foram investigadas as características sensoriais, químicas e microbiológicas dessa massa alimentícia de mandioca e também parâmetros que interferem na vida de prateleira do produto final. A variedade de mandioca foi a IAC 576-70, classificada como de mesa, colhida com idade fisiológica de 14 meses e estocada por 24 horas. Em seguida as raízes foram descascadas, cortadas em toletes e retirado o cordão central nas raízes. Foram colocadas em alto clave a 100ºC por 40 minutos e em seguidas moídas onde receberam adição de maltodextrina de amido de milho waxy 0, 5, 10 e 15%, para a diminuição da retrogradação e adição de ácido cítrico a 1% no controle da contaminação microbiológica. As amostras foram acondicionadas em embalagens de polietileno e armazenadas a temperatura refrigerada (10ºC ± 0,5 ºC) e em temperatura ambiente, para análises físico, químicas e microbiológicas. Os lotes de amostras foram produzidos em triplicatas com 7 períodos de avaliações (0, 2, 4, 6, 8, 10 e 12). Houve diferenças estatisticamente significativas (p≤0,01) tanto em relação ao tempo como ao armazenamento para os teores de açúcar redutor, acidez titulável e textura, e os teores de umidade e pH não variável significativamente. O tratamento com adição de maltodextrina a 15% apresentou o melhor resultado contra o aumento da textura. O comportamento destes fatores durante a vida de prateleira não afetou os parâmetros sensoriais avaliados em produtos culinários da massa (purê e mandioca frita). Não ocorreu sinérese nas amostras. Aos sete DAP (dias após o preparo), a contaminação microbiológica na condição ambiente foi visualmente 2 alta, sendo descartado esse lote. O lote em condição refrigerado seguiu suas avaliações até o 14º DAP. / Abstract: This work had as objective the development of a nutritious mass produced starting from cooked cassava for use in the several ends culinary. Were investigated the sensorial characteristics, physics chemistries and microbiological this foodstuffs mass of cassava and also parameters that interfere in the shelf life of the finish product. The cassava variety was IAC 576-70, classified as of table, picked with physiologic age of 14 months and stocked by 24 hours and soon afterwards they were peeled, cut in thole and withdraw central cord in the roots. They were put in high key to 100ºC for 40 minutes and soon afterwards ground where received treatments with addition of maltodextrina of starch of corn waxy 0 were, 5, 10 and 15%, and citric acid addition to 1% that searched for to reduce the retrogradação and to control the contamination microbiological. The samples were conditioned in packings of polyethylene and stored the refrigerated temperature (10ºC ± 0,5 ºC) and in room atmosphere. The lots of samples were produced in triplicates with 7 periods of evaluations (0, 2, 4, 6, 8, 10 and 12). There were significant differences statistically (p≤0,01) so much in relation to the time as to the storage for the tenors of sugar reducer, acidity titulável and texture, and the humidity tenors and pH they stayed unaffected. The treatment with maltodextrina addition to 15% presented the best result against the increase of the texture. The behavior of these factors during the shelf life didn't affect the appraised sensorial parameters in culinary products of the mass (purée and fried cassava). It didn't happen syneresis in the samples. To seven DAP (days after the preparation), the contamination microbiological in the environment condition was visually high, being discarded this lot. The lot in condition refrigerated followed their evaluations until 14th DAP. / Mestre

Recent research has focused on the molecular characterization of null waxy (Wx), 'Wx-A1b, Wx-B1b', and 'Wx-D1b', alleles that produce no detectable Wx proteins in the endosperm starch of allohexaploid wheat (<i>Triticum aestivum</i> L.; 2n = 6x = 42; AABBDD). The major objectives of this thesis were to (1) isolate and characterize a Wx wheat cDNA and (2) to identify aberrant 'Wx' transcripts encoded by the null 'Wx-A1b' allele of CDC Wx2, a waxy hexaploid wheat line, which result in an absent Wx-A1 protein (~59 kD). In the first study, a cDNA library prepared from developing wheat kernels (cv. Fielder) was screened using a homologous PCR-digoxigenin labeled wheat cDNA probe. A 2.2 kb cDNA clone denoted GBSSIMMI (Accession no. Y16340) was sequenced and identified as encoding a Wx-D1 protein. The deduced amino acid sequence showed 94% similarity with a wheat Wx-A1 peptide, 96% similarity with a wheat Wx-B1 peptide, and 100% identity with two wheat Wx-D1 peptides. A 33-nucleotide deletion, encoding 11 amino acids (AMLCRAVPRRA), was detected within the GBSSIMMI cDNA relative to a previously isolated wheat cDNA (accession no. X57233). Complementation analysis using a glycogen synthase deficient 'E. coli' strain and an 'in vitro' starch synthase assay did not indicate that GBSSIMMI encoded a functional Wx-D1 protein. In the second study, two sister lines CDC Wx2 and CDC Wx6 were obtained by crossing lines Bai-Huo (carries null 'Wx-D1b' allele; lacks Wx-D1 protein) and Kanto 107 (carries null 'Wx-A1b' and -'B1b' alleles; lacks Wx-A1 and -B1 proteins). Waxy protein profiling, amylose concentration determinations, Northern blot analysis, and reverse transcriptase PCR (RT-PCR) analysis were conducted. Ten RT-PCR derived cDNA clones were selected from each genotype and characterized by DNA sequencing analyses. The waxy phenotype of CDC Wx2, lacking Wx-A1, -B1, and -D1 proteins and possessing a reduced amylose concentration ~4%), was associated with dramatically reduced levels of a 2.4 kb 'Wx' transcript when compared to the higher levels in a wildtype control line. DNA sequencing of clones from Kanto 107 and CDC Wx2 characterized two types of aberrant 'Wx' transcripts, one containing intron 1 and another containing introns 1 and 4. Intron 1 in both types of aberrant 'Wx' transcripts contained a premature stop codon which resulted in the translation of a truncated Wx protein ~4 or 11 kD). Analysis of CDC Wx6, lacking Wx-B1 and -D1 proteins and possessing a reduced amylose concentration (~14%) failed to reveal aberrant ' Wx' transcripts, suggesting that the RNA defects in this study were not responsible for the absence of the Wx-B1 or -D1 proteins. Thus, the aberrant Wx transcripts were encoded by the null 'Wx-A1b' allele. The presence of a premature stop codon in the 'Wx' transcripts encoded by the null 'Wx-A1b' allele explained the absence of the ~59 kD Wx-A1 protein in CDC Wx2 and its parental line Kanto 107.

Dans le but d'identifier des critères de sélection du blé (T. aestivum L.) destiné à la production de bioéthanol, les objectifs de cette thèse étaient (1) de mettre en évidence les caractéristiques physico-chimiques du grain associées aux rendements en glucose et éthanol, et (2), d'étudier par approche protéomique l'effet de variants génétiques affectant la quantité d'amylose sur le métabolisme des sucres et de l'amidon. L'analyse de trente variétés implantées dans un essai multilocal pluriannuel a mis en évidence l'importance du taux de protéines, de la dureté et de la distribution des granules d'amidon sur les rendements en glucose et éthanol. Dans une moindre mesure, la composition allélique des protéines de réserves et la viscosité des arabinoxylanes ont également un effet lors de l'étape de transformation de l'amidon en sucres fermentescibles. Huit lignées isogéniques waxy de trois variétés françaises ont été implantées dans un essai multilocal. Les lignées dépourvues d'amylose ont produit moins de glucose et d'éthanol que les variétés normales. Les analyses protéomiques des protéines de l'albumen (albumines, globulines et amphiphiles) ainsi que des protéines associées aux granules d'amidon des grains matures des lignées isogéniques de la variété Trémie ont mis en évidence : (1) une relation entre le volume spécifique des GBSS et la quantité d'amylose et (2) une modification de l'expression d'enzymes impliquées dans le métabolisme des sucres et de l'amidon (Susy, AGPase, fructose biphosphate aldolase) mais aussi de protéines de stress et de défense (serpines et HSP). Ces observations suggèrent un développement du grain incomplet pour la lignée dépourvue d'amylose.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Master of Science / Department of Grain Science and Industry / Yong Cheng Shi / Waxy wheat starch (WWS) containing little or no amylose has unique properties for food and industrial uses. Hydroxypropylation, a widely used means for modifying starches, could enhance functionalities of starch by substituting hydroxyl groups in starch. There are limited numbers of literatures regarding hydroxypropylation of WWS. WWS hydroxypropylated with 3.0-9.0% propylene oxide (PO) were prepared and compared to hydroxypropylated normal wheat starch (NWS) and hydroxypropylated waxy maize starch (WMS). The molar substitution (MS) of the resulting hydroxypropylated NWS, WWS and WMS was 0.055-0.151, 0.048-0.133, and 0.049-0.139, respectively. Gelatinization temperatures and enthalpy of hydroxypropylated starches were significantly lower than those of their unmodified counterparts and the extent of decrease was positively correlated to the MS. Differential scanning colorimetry (DSC) results showed that hydroxypropylation reduced the retrogradation of the starches during the storage after gelatinization but there were differences between the starches. For the same level of PO reaction (3 and 5% PO), hydroxypropylated WWS retrogradated less than hydroxypropylated WMS, suggesting that for the same level of cold storage stability, less PO is needed for WWS. After reacted with 6% PO, MS was 0.092 and 0.094, respectively, for WWS and WMS, and no retrogradation was observed for those hydroxypropylated starches, indicating that at MS ~0.094, hydroxypropyl groups prevents amylopectin chains from re-associating and forming crystalline structures. In contrast, a higher level of PO (9%) was needed to react with NWS to achieve the hydroxypropylated starch with an MS of 0.151 that gave no retrogradation. Consistent with microscopic observation results, Micro-Visco-Amylograph (MVA) analysis showed hydroxypropylated starches developed viscosity at lower temperatures and had improved hot and cold viscosities. The specific characteristics of hydroxypropylated starches are related to the degree of hydroxypropylation. Therefore, it is critical to determine the level of hydroxypropylation in modified starches. 1H NMR is a simple and rapid means of determining hydroxypropyl (HP) group in modified starches. In this study, a method to prepare a HP starch for NMR analysis was improved. The optimum parameters proposed to hydrolyze HP starches were 10% starch solid content, 3.5% (wt.%) DCl in D2O as the solvent, sodium acetate as an internal standard, heating at 90oC for 1 h. Optionally, 6% (v/v) trifluoroacetic acid-d as the water-peak shifting reagent. Six hydroxypropylated starch samples and two commercial cross-linked and hydroxypropylated starch samples were hydrolyzed with this modified method before 1H NMR analysis, and the results of HP group content in the samples were in agreement with the results from an enzyme-catalyzed method, which indicate that the improved acid hydrolysis method is applicable for both hydroxypropylated starch and cross-linked and hydroxypropylated starch.

Triticale belongs to the amphiploid cereals and was derived by crossing wheat and rye. Its baking quality is substantially worse than in wheat. The baking quality is determined by a composition and a content of the storage proteins. Both high and low molecular glutenin subunits have a major effect on the final quality of dough. The secalins of rye belong amongst the storage proteins of triticale, which negatively influence the baking quality. These are the reasons why lineages having translocated chromosome 1R and containing subunit Glu-D1d, which positively influences the baking quality, were created. The thesis is focused on identification of the allelic composition of loci of high molecular glutenin subunits (HMW-GS), low molecular glutenin subunits (LMW-GS), loci Pina a Pinb and null alleles of Waxy genes. 23 selected genotypes of triticale were analysed by using DNA markers based on polymerase chain reaction (PCR). Allelic composition of loci HMW-GS (Glu-A1, Glu-B1, Glu-D1), LMW-GS (Glu-A3) and Pina-D1, Pinb-D1 was described and null alleles were detected in the loci Wx-A1 and Wx-B1.