A computer simulation of the dynamics of bubble growth and shrinkage during extrudate expansion

Fan, J.; Mitchell, John R.; Blanshard, J. M. V.

doi:10.1016/0260-8774(94)90058-2

Cited by 118 publications

(64 citation statements)

References 11 publications

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“…Shrinkage and collapse after expansion were also observed at high-moisture content. 16,35,36 Moisture content effects on expansion became less important at high screw configuration at 400 rpm screw speed. Starch molecules would be highly degraded at high shearing, resulting in lower viscoelasticity that cell wall cannot sustain the pressure generated from moisture.…”

Section: Extrudate Expansion and Strengthmentioning

confidence: 94%

“…12 T g of the melt exiting the extruder was also related to extrudate collapse after extrusion. 16 Bhuiyan and Blanshard 17 showed that low-gelatinization temperature, rapid gelatinization process, and high-amylose content were favorable to extrusion. Flow and melting properties of corn endosperm determined by using capillary rheometry were also related to material behavior during extrusion.…”

mentioning

confidence: 98%

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Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Blanche

Sun

2004

Adv Polym Technol

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ABSTRACT:The objective of this study was to investigate the relationships between starch melt transition characteristics, extrusion conditions, and final product properties. Cornstarch was extruded using a corotating twin-screw extruder at varying moisture content, medium/high screw configuration, and 300/400-rpm screw speeds. Extrudates were evaluated for bulk density, expansion ratio, cell structure, bending strength, thermal and pasting properties. Temperature change ( T) was defined as the temperature difference between the native starch melting temperature and its melt temperature just behind the die during extrusion at a given moisture content. T was significantly affected by starch moisture content and mechanical shearing, which controlled the melting behavior of the starch in the barrel. Amylose-lipid complex formation during extrusion increased as T increased and leveled off at T of about 20• C. Pasting peak viscosity of the starch extrudates decreased as T increased and leveled off at T of about 15• C. Within the same range of mechanical shearing intensity, extrudate bulk density and bending strength decreased linearly as T increased. Extrudate expansion was negatively correlated to bulk density. C

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Section: Extrudate Expansion and Strengthmentioning

confidence: 94%

mentioning

confidence: 98%

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Blanche

Sun

2004

Adv Polym Technol

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“…In recent studies, this approach was applied to extrusion cooking of starch-based materials. Fan et al [10] have integrated T g in a model to describe expansion characteristics of extruded products. Kaletunc and Breslauer [11], Nicholls et al [12] and Barrett and Kaletunc [13] have used T g to evaluate the effect of processing conditions on the textural attributes of extrudates.…”

Section: Introductionmentioning

confidence: 99%

Glass Transition of Extruded Wheat, Corn and Rice Starch

Bindzus

Livings²,

Gloria-Hernández

et al. 2002

Starch/Stärke

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Commercial wheat, corn and rice starch were extrusion cooked under a specific mechanical energy input (SME) ranging from 81 to 365 Wh/kg (288 to 1314 kJ/kg). Extrusion cooking at low and high SME resulted in products having significant differences in molecular weight distribution and having crystalline structures of the V-and E-type, as determined by gel permeation chromatography and X-ray diffraction analysis. Differential scanning calorimetry revealed that the glass transition temperature (T g ) of the extruded starches was independent of the botanical source, the degree of extrusion-induced molecular fragmentation and the formation of the V-and E-type crystalline structures. The obtained master curve, defined by the relationship between water content and T g of the amorphous starch, may be used as a predictive tool in modelling the extrusion process of starch or starch containing blends, especially with regard to the formation of the morphological structure and texture attributes of directly expanded products.

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“…Esta variável resposta está relacionada com a capacidade da estrutura do expandido que mantém a integridade das bolhas no material fundido ao sair da matriz do extrusor, sendo que em altas temperaturas ocorre grande redução da viscosidade do produto amiláceo por causa da desintegração do amido propiciando a perda do vapor de água retido na estrutura, ocasionando colapso das bolhas de ar diminuindo o IE [20,31,37].…”

Section: Tamanho De Partícula (Mm)unclassified

Caracterização da farinha de bagaço de jabuticaba e propriedades funcionais dos extrusados

Ascheri¹,

Ascheri²,

Carvalho³

2006

Ciênc. Tecnol. Aliment.

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RESUMOEstudaram-se as características de farinha de bagaço de jabuticaba fermentado e algumas propriedades funcionais (índice de expansão e índice de solubilidade) dos extrusados elaborados a partir deste bagaço e arroz, em proporções que variaram de 11,59 a 25% (bagaço/arroz). A farinha de bagaço de jabuticaba fermentado foi avaliada quanto à distribuição do tamanho de partícula, cor, sabor e aroma, composição centesimal, minerais e fibras. Algumas das características desta farinha foram comparadas com as das farinhas de bagaço de jabuticaba doce (sem fermentar) e arroz polido. O extrusor utilizado para obtenção das farinhas pré-gelatinizadas constituiu-se em um único parafuso com taxa de compressão de 1:3, com rotação variável (65,90 a 234,10 rpm). Usou-se uma matriz circular de 3 mm e uma taxa de alimentação de 5 kg/h. As temperaturas da 1 a e 2 a zonas de aquecimento do extrusor foram mantidas fixas (50 e 100 °C, respectivamente) e a 3 a zona variou entre 99,54 e 200,46 °C. A Metodologia de Superfície de Resposta foi usada para avaliar a tendência das propriedades funcionais frente às variações de bagaço na formulação e dos parâmetros do processo (temperatura e rotação do parafuso). Os resultados mostraram que a farinha de bagaço de jabuticaba fermentado é uma boa fonte de fibras, de proteínas e de minerais, constituída de partículas finas com aroma característico do fruto e de sabor azedo-adstringente e ligeiramente salgado. A expansão dos extrusados aumentou com o aumento da rotação do parafuso e diminuiu com o aumento da adição de farinha de bagaço de jabuticaba, apresentando um comportamento quadrático com o aumento da temperatura. O índice de solubilidade aumentou com o aumento da rotação do parafuso e com a diminuição da temperatura. Maiores índices de expansão (3,26) e de solubilidade (17,55%) foram alcançados numa formulação contendo aproximadamente 10% de bagaço de jabuticaba fermentado a 240 rpm e temperaturas de 130 e 100 °C, respectivamente. A farinha de bagaço de jabuticaba fermentado misturada com farinha de arroz polido poderá ser usada como matéria-prima para a produção de farinhas pré-gelatinizadas, se as circunstâncias operacionais apropriadas forem aplicadas. Palavras-chave: extrusão termoplástica, farinha de arroz, jabuticaba, metodologia de superfície de resposta, aproveitamento de resíduo agroindustrial. SUMMARY CHARACTERIZATION OF JABOTICABA BAGASSE FLOUR AND FUNCTIONAL PROPERTIES OF EXTRUDATES.The physical properties of fermented Jaboticaba bagasse flour and some functional properties (expansion index and water solubility index) of the extrudates obtained from mixtures of rice and Jaboticaba bagasse flour were studied, which varied from 11.59 to 25.00% (bagasse/rice). The fermented Jaboticaba bagasse flour analyzed the particle size distribution, color, flavor and chemical composition. Some of these properties were compared with the non-fermented Jaboticaba bagasse and white rice. A single screw extruder with a compression rate of 1:3 fitted with a round die of 3 mm diameter was used ...

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A computer simulation of the dynamics of bubble growth and shrinkage during extrudate expansion

Cited by 118 publications

References 11 publications

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Glass Transition of Extruded Wheat, Corn and Rice Starch

Caracterização da farinha de bagaço de jabuticaba e propriedades funcionais dos extrusados

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