Made available in DSpace on 2014-06-11T19:24:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-16Bitstream added on 2014-06-13T19:11:27Z : No. of bitstreams: 1 albano_km_me_sjrp_parcial.pdf: 340564 bytes, checksum: c6ce981330c90d89191b5b8502042821 (MD5) Bitstreams deleted on 2014-10-03T16:24:35Z: albano_km_me_sjrp_parcial.pdf,Bitstream added on 2014-10-03T16:27:33Z : No. of bitstreams: 2 albano_km_me_sjrp_parcial.pdf.txt: 20511 bytes, checksum: 5a8335baa2146e89442699e67564cd3b (MD5) 000685078.pdf: 2223223 bytes, checksum: 27dffa36eb5db695c0921edfc2a2a141 (MD5) Bitstreams deleted on 2014-10-03T16:33:11Z: 000685078.pdf,Bitstream added on 2014-10-03T16:43:25Z : No. of bitstreams: 2 albano_km_me_sjrp_parcial.pdf.txt: 20511 bytes, checksum: 5a8335baa2146e89442699e67564cd3b (MD5) 000685078.pdf: 2223223 bytes, checksum: 27dffa36eb5db695c0921edfc2a2a141 (MD5) Bitstreams deleted on 2014-10-03T16:48:51Z: 000685078.pdf,Bitstream added on 2014-10-03T16:49:44Z : No. of bitstreams: 1 000685078.pdf: 2223223 bytes, checksum: 27dffa36eb5db695c0921edfc2a2a141 (MD5) Bitstreams deleted on 2014-10-27T11:47:01Z: 000685078.pdf,Bitstream added on 2014-10-27T11:48:02Z : No. of bitstreams: 1 000685078.pdf: 2223223 bytes, checksum: 27dffa36eb5db695c0921edfc2a2a141 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os amidos, além da sua importância nutricional, apresentam um importante papel tecnológico em alimentos processados. As propriedades funcionais dos amidos, como a relação amido-água, temperatura de gelatinização, formação de gel e viscosidade de pasta definem o uso industrial e o consumo. Por outro lado, a composição e a estrutura dos grânulos variam com a fonte botânica, afetando suas propriedades e funcionalidade. O amido de mandioquinha-salsa é considerado de fácil cozimento, apresentando baixa temperatura de gelatinização e alta viscosidade de pico. Também possui baixa tendência à retrogradação e sinérese, o que contribui para sua alta digestibilidade. O comportamento reológico dos géis de amido de mandioquinha salsa nas concentrações de 2, 6 e 10% e temperaturas de 10, 30, 50 e 70 ºC foi estudado em cisalhamento estado estacionário e oscilatório. No estado estacionário com taxa de deformação de 1 a 1000 s -1 foi ajustado o modelo da Lei da Potencia às curvas de fluxo e os resultados mostraram que os géis de amido apresentam comportamento pseudoplástico (n < 1) nas concentrações e temperaturas estudadas, elevado grau de tixotropia, sendo esta mais acentuada na maior temperatura (70 ºC) e na menor concentração (2 %). O gap usado nos ensaios reológicos com placas paralelas teve forte influência nos parâmetros reológicos dos géis de amido, diminuindo a viscosidade aparente para uma mesma taxa de deformação, havendo a estabilização das medidas reológicas no gap de 800 μm. A temperatura teve forte influência na reologia do gel, que apresentou maior energia de ativação em maiores concentrações. No estado oscilatório foram avaliados a faixa de deformação para... / Starches have a great nutritional and technological importance in processed foods. Functional properties, such as gelatinization temperature, gel formation and paste viscosity, define the industrial use and the consumption. Moreover, the composition and structure of the granules vary with the botanical source, affecting their properties and functionality. The Peruvian carrot starch is considered easy to cook, with a low gelatinization temperature and high viscosity peak. It also has a low tendency to retrogradation and syneresis, which contributes to high digestibility. The rheological behavior of starch gels from Peruvian carrot at concentrations of 2, 6 and 10 % and temperatures of 10, 30, 50 and 70 ºC have been studied in steady shear and oscillatory shear. In steady state and shear rate from 1 to 1000 s -1 power law model was adjusted to the flow curves and the results showed that the starch gels present pseudoplastic behavior (n <1) in the studied range of concentrations and temperatures, high degree of thixotropy, which is more pronounced at higher temperature (70 ºC) and at the lowest concentration (2 %). The gap used in the rheological measurements with parallel plates had a strong influence on the rheological parameters of starch gels, reducing the apparent viscosity for the same shear rate, with stabilization of rheological measurements in the gap of 800 µm. Temperature had strong influence on the gel with higher activation energy at higher concentrations. In oscillatory shear the strain range for linear viscoelasticity was assessed, as well as the frequency ramp, phase angle, and complex viscosity (*). All samples showed mechanical spectra with the loss modulus (G”) increasing faster with frequency than the... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:23:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-27Bitstream added on 2014-06-13T20:10:53Z : No. of bitstreams: 1 rocha_ts_me_sjrp.pdf: 4148399 bytes, checksum: ce0ff94a04b39123b97024a446e8f545 (MD5) / Enzymatic hydrolysis of granular starch has been used to study the structure and the physicochemical properties of the granules. It depends, among others, on the starch botanic source, on the enzymatic system used and on the size of the granules. The aim of this work was to investigate the effect of granule size on enzymatic susceptibility and on structural and physicochemical properties of Peruvian Carrot starch. Starches from two varieties (Amarela de Carandaí, AC and Amarela de Senador Amaral, ASA) were isoladed, fractionated by size and classified into whole granules (without separation); large granules (d 20æm); medium granules (> 10 e < 20æm) and small granules (£ 10æm). The whole and fractionated granular starches were hydrolysed with bacterial -amylase and fungal amyloglucosidase. Samples, before and after hydrolysis, were analyzed regarding their structural and physicochemical characteristics. The whole and fractionated native starches shown in optical microscope and scanning electron microscope circular shape for large granules and polygonal shape for small granules. The granular surface was smooth with some had openings, especially for the larges granules, with some depressions and holes. From chromatograms of gel permeation in Sepharose CL-2B was not possible to observe differences on the molecular size from both varieties of Peruvian Carrot. The amylose content, that was higher to AC variety, was concentraded mainly in large granules. Both varieties exhibited B-type X-ray diffraction pattern and relative degree of cristallinity (DC) (~20%) was not different for the different starches, despite the intensity of the peaks decrease for small granules. The intrinsic viscosity of starches from both varieties was smallest 24% and 14%, respectively, to small granules in relation of large granules. Gelatinization temperatures, from DSC, decreased as the granule sizes decreased, while the enthalpy remained the same. The smaller the granule