Relationships between residence time and process variables in a corotating twin-screw extruder

Gogoi, Binoy K.; Yam, Kit L.

doi:10.1016/0260-8774(94)90185-6

Cited by 47 publications

(45 citation statements)

References 9 publications

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“…When the screw speed is increased, the energy supplied by friction also increases because it is proportional to the velocity of the powder particles in the barrel. At the same time the quantity of heat transfer by conduction from the barrel wall decreases as the particle velocity increases, since the residence time of the product at the hot barrel wall decreases (2,38,39). Thus, the final dough temperatures would be dependent on the result of this combination effect, i.e.…”

Section: Effect Of Screw Speedmentioning

confidence: 93%

Effects of Lipids and Processing Conditions on Degree of Starch Gelatinization of Extruded Dry Pet Food

Lin

Hsieh

Huff

1997

LWT - Food Science and Technology

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Section: Effect Of Screw Speedmentioning

confidence: 93%

Effects of Lipids and Processing Conditions on Degree of Starch Gelatinization of Extruded Dry Pet Food

Lin

Hsieh

Huff

1997

LWT - Food Science and Technology

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“…On one hand, increasing screw speed and barrel temperature will introduce more energy to the material in the barrel, which would enhance the moisture evaporation at the die exit and hence increase ER. On the other hand, increasing screw speed will reduce the residence time of the material (Gogoi and Yam 1994), which could reduce the energy received by the material in the barrel, and therefore could result in lower ER. Sun and Muthukumarappan (2002) reported similar results when screw speed increased from 180 to 200 rpm and 220 rpm.…”

Section: Expansion Ratio (Er)mentioning

confidence: 98%

Twin-screw Extrusion of Corn Flour and Soy Protein Isolate (SPI) Blends: A Response Surface Analysis

Ramaswamy

Boye

2009

Food Bioprocess Technol

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The effects of feed moisture, screw speed, and barrel temperature on physical properties of extruded corn flour and soy protein isolate (SPI) blends were investigated in a co-rotating twin-screw extruder using a response surface methodology. Corn flour and SPI were mixed with a ratio of 4:1. The screw speed was set at five levels between 60 and 140 rpm, barrel temperature between 140°C and 180°C, and feed moisture between 18% and 38%. All physical properties of the extruded material evaluated-included expansion ratio, bulk density, breaking strength, water solubility index, rehydration ratio, and color-were significantly (p<0.05) affected by the three process variables. Feed moisture was the most significant variable with quadratic effects on most of the physical properties. Response surface regression models were established to correlate the physical properties of the extruded product to the process variables. Understanding the effect of these variables on the product physical properties was deemed useful for the development of protein-rich extruded products.

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“…The expansion is influenced by physicochemical changes that occur during the extrusion, such as the gelatinization degree (Chinnaswamy;Bhattacharya, 1983;Feillet, 1975) and the molecular degradation of starch (Cai;Diosady, 1993;Gomez;Aguilera, 1983;Kirby et al, 1988). For this reason, the variables which influence the volume of the expanded are the extrusion temperature, the humidity, the rotation speed and the screw configuration, and array geometry Hanna, 1987;Colonna;Tayeb;Mercier, 1989;Gogoi;Yam, 1994; Owusu-Ansah; Van de Voort;Syanley, 1983). Higher temperatures in the 3 rd zone of the extruder might have provoked higher protein denaturation with consequential increase in the protein-protein and protein-starch interactions, harming the expansion.…”

Section: Resultsmentioning

confidence: 99%

Physical and sensory characteristics of pellets elaborated with different levels of corn grits and whey protein concentrate

et al. 2016

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Whey has proteins of high biological value, which has been used as an ingredient in the elaboration of yogurt, milk beverages and as protein concentrates. Food extrusion stands out as one of the most efficient cooking techniques, allowing a number of product types, from soluble flour to convenience products, such as snacks, which have high acceptability by the consumers. Products processed by extrusion, such as those expanded by frying (pellets), have high carbohydrate content, and its enrichment with protein can favor its nutritional aspect. This study aimed to use the whey protein concentrate (WPC) in combination with corn grits in the preparation of pellets. Absolute density, density of expanded pellets, color, crispness index, and pellet sensory acceptance were determined. For the absolute density, contents from 5% to 17% produced denser non-expanded pellets. The higher the WPC content and the temperature of the extruder, the higher the density of the expanded pellets. The crispness index was not altered by the protein content and by the extruder temperature. In the sensory analysis, the preferred samples were the ones with lower WPC levels (5%). We concluded that higher WPC values in the pellets formulation increased their density, but did not alter color and texture, as well as small WPC levels did not affect the acceptance of snacks.Index terms: Extrusion; sensory; texture. RESUMOO soro lácteo possui proteínas de alto valor biológico, e que vem sendo utilizado como ingrediente na elaboração de iogurtes, bebidas lácteas e na forma de concentrados proteicos. A extrusão de alimentos, destaca-se entre as mais eficientes técnicas de cozimento, proporcionando inúmeros tipos de produtos, desde farinhas solúveis a produtos de conveniência como snacks, apresentando alta aceitabilidade pelos consumidores. Produtos processados por extrusão, como os expandidos por fritura (pellets) apresentam teor elevado de carboidratos, e seu enriquecimento com proteína, pode favorecer o aspecto nutricional do mesmo. Neste trabalho, objetivou-se utilizar o concentrado proteico de soro lácteo (WPC) em combinação com o gritz de milho na elaboração de pellets. Foram determinadas a densidade absoluta, densidade dos pellets expandidos, diferença de cor, índice de crocância, além da aceitação sensorial dos pellets. Para a densidade absoluta, teores de 5 a 17% de WPC deixaram os pellets não-expandidos mais densos. Quanto maior foi o teor de WPC e a temperatura do extrusor, maior foi a densidade dos pellets expandidos. O índice de crocância não foi alterado pelo teor de proteína e temperatura do extrusor. Na análise sensorial, as amostras mais preferidas foram as com menores teores de WPC (5%). Concluímos que maiores valores de WPC nas formulações dos pellets aumentaram a densidade dos mesmos, mas não alteraram a cor e a textura, assim como pequenos teores de WPC não alteraram a aceitação dos snacks.

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Relationships between residence time and process variables in a corotating twin-screw extruder

Cited by 47 publications

References 9 publications

Effects of Lipids and Processing Conditions on Degree of Starch Gelatinization of Extruded Dry Pet Food

Effects of Lipids and Processing Conditions on Degree of Starch Gelatinization of Extruded Dry Pet Food

Twin-screw Extrusion of Corn Flour and Soy Protein Isolate (SPI) Blends: A Response Surface Analysis

Physical and sensory characteristics of pellets elaborated with different levels of corn grits and whey protein concentrate

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