The influence of specific mechanical energy on cornmeal viscosity measured by an on-line system during twin-screw extrusion

Chang, Yoon Kil; Martı́nez-Bustos, Fernando; Park, T. S.; Kokini, Jozef L.

doi:10.1590/s0104-66321999000300007

Cited by 45 publications

(40 citation statements)

References 18 publications

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“…In this case, starch molecules can be depolymerized easily by heated or heated-sheared treatment, and the shear force in addition to the heat treatment contributed significantly to molecular cleavage [25] . Chang et al [26] adds that starch granules may resist under high moisture or low shear conditions, but with the increasing severity of treatment, the granules lose their semi-crystalline character.…”

Section: Functional Propertiesmentioning

confidence: 99%

Characterization of cassava starch processed in an internal mixer

et al. 2013

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An internal mixer connected to a torque rheometer was used to investigate the effect of moisture content (13.2 to 46.8 g.100g -1 ), rotation speed (13.2 to 46.8 rpm) and processing temperature (53.2 to 86.8 °C), applying a factorial central composite design, on the specific mechanical energy (SME), pasting viscosity and crystallinity of cassava starch. Torque values were highly significant for the three variables, showing decrease with increasing moisture, temperature and rpm. The highest cold viscosity (CV) was obtained at 13.18 g.100g -1 moisture, 86.87 °C and 30 rpm due to increased rupture of starch granules caused by processing at lower moisture condition. Peak viscosity (PV) values were higher than CV values which indicated that the processing was not able to destroy completely the molecular integrity of the starch granules. Smaller setback (SB) at high temperature and rpm and low moisture showed possible starch depolymerization causing loss of recrystallization capacity. Processing under low moisture content resulted in reduction of crystallinity. The results showed that the effect of moisture was more pronounced than rotation speed and processing temperature of cassava starch.

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Section: Functional Propertiesmentioning

confidence: 99%

Characterization of cassava starch processed in an internal mixer

et al. 2013

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“…When the screw speed was increased, the SME values were increased in both corn meal and wheat starch extrudates. 52,53 This was attributed to the greater frictional heat and simultaneous increase in temperature. Other authors reported that higher SME values in the wheat extrusion process produced greater starch conversion and degradation 54 and lower viscosity.…”

Section: Penetration Force (Pf)mentioning

confidence: 99%

“…Other authors reported that higher SME values in the wheat extrusion process produced greater starch conversion and degradation 54 and lower viscosity. 52 This suggests that starch plays a key role in the rheological properties 52 and can affect characteristics such as gelatinisation, expansion, BD and fragility (texture) of the extruded products. 27,41,43 This response shows a high degree of association (at p < 0.001) with EI (r = 0.95) and BD (r = À0.92).…”

Section: Penetration Force (Pf)mentioning

confidence: 99%

Effect of the addition of calcium hydroxide on some characteristics of extruded products from blue maize (Zea mays L) using response surface methodology

et al. 2001

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The aim of this research was to study the effects of calcium hydroxide (0±0.2%) and screw speed (100±180 rpm) on the expansion index (EI), bulk density (BD), penetration force (PF) and speci®c mechanical energy (SME) values of blue maize meal extrudates. Blue maize meal was extruded using a commercial extruder (Brabender 20DN/8-235-00) with a compression screw ratio of 3:1. A second-order, central composite experimental design was used. It was found that the EI and SME values decreased and the BD and PF values increased when the calcium hydroxide concentration was increased. The screw speed had a signi®cant effect only on the SME and PF values. Quadratic model ®tness was shown for all responses, with values of R 2 > 0.74, p of F (model) <0.01 and variability coef®cient <13.3% (except for PF, 29.18%), and for almost all cases there was no lack of ®t (p > 0.055). Calcium hydroxide concentration showed good correlation (p < 0.01) with EI (r = À0.81), PF (r = 0.60), SME (r = À0.76) and BD (r = 0.83). However, screw speed was marginally or not correlated (r < 0.36, p > 0.14) with the responses. The results suggest that it is possible to produce appropriate extruded products from blue maize forti®ed with calcium in an optimised calcium hydroxide concentration and screw speed range of 0.02±0.078% and 117±180 rpm respectively.

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“…Desta forma, o aumento do IE pode estar relacionado com a maior redução do peso mo- FBJ RP IE lecular da matriz amilácea fundida no interior do extrusor o que pode ter contribuído para reduzir a resistência da matriz polimérica à pressão interna das bolhas, que irão favorecer a maior porosidade da estrutura final das farinhas mistas extrusadas. No entanto, alta quebra molecular pela ação da energia mecânica pode, ao contrário, reduzir a expansão final do extrusado [14], que neste caso não foi suficientemente grande para reduzir o IE. A relação inversa entre a porcentagem de farinha de bagaço de jabuticaba e o IE se deve à diminuição da proporção de material amiláceo na mistura e as fibras incluídas não fornecem suficiente material viscoso, afetando as propriedades reológicas do produto extrusado.…”

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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The influence of specific mechanical energy on cornmeal viscosity measured by an on-line system during twin-screw extrusion

Cited by 45 publications

References 18 publications

Characterization of cassava starch processed in an internal mixer

Characterization of cassava starch processed in an internal mixer

Effect of the addition of calcium hydroxide on some characteristics of extruded products from blue maize (Zea mays L) using response surface methodology

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

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