摘要:

ABSTRACTA review of fundamental and engineering aspects of extrusion in a single‐screw is given. Attention is focussed on flow patterns, flow rates, residence time distributions and power consumption as a function of extruder design and screw rotation speed. The relationship for these engineering variables in extrusion of a purely Newtonian liquid and a power law liquid are reviewed. Where possible these relationships are compared with experimental results from the literature (corn‐grits) and with our own measurements on biopolymers (corn‐grits, defatted soy flour, modified di‐amylo

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00193.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA five parameter semi‐empirical model is developed describing the apparent viscosity of a cooking dough as a function of applied shear rate, temperature, and time‐temperature history. Such a model will be useful in the mathematical simulation of the extrusion cooking process.Other factors which can affect the apparent viscosity of a cooking dough are also discussed. The viscosity model is verified and the constants evaluated for a typical dough by combining the results of Amylograph and capillary viscometer experime

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00194.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA simple capillary ram food extruder was designed, constructed and mathematically modeled. The mathematical model was developed from a group of meaningful dimensionless parameters derived from a dimensional analysis of the extruder. This approach to modeling greatly reduced the number of experiments required to determine the model equation constants.Commercial defatted soy flour was used to conduct tests for validating the model. Flour moisture content, die length and die diameter were varied with all other variables remaining constant. Pressure loss through the extruder was the measured variable.The mathematical model fit the observed data accurately. It is proposed that once all experimental constants are determined, the general model may be used to determine rheological and thermodynamic data for doughs during extrusion processes. These data may then be used to develop certain rheological material functions.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00195.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA simple model was used to correlate extrusion dough viscosities with moisture, temperature and shear rate. The parameters were fit to the model for a pregelatinized corn flour dough. The effect of two additives, sodium stearoyl‐2‐tactylate and a diacetyltartaric acid ester of monoglycerides, were also explored using the pregelatinized corn flour system. Moisture, extrusion temperature and sodium stearoyl‐2‐lactylate levels were correlated to the viscosity of the pregelatinized corn flou

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00196.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTEffects of moisture level, temperature and shear rate on the rheological properties of defatted soy dough during extrusion were studied on a Brabender laboratory extruder. Entrance pressure loss through the extruder capillary die as well as viscosity of the cooked and compressed soy dough were expressed as a function of added moisture, shear rate and temperature through multiple regression analysis. Process conditions involved in this study were (a) temperature from 100 to 160°C; (b) added moisture from 22 to 32% and (c) shear rate from 50 to 10,500 sec−1. Data were collected at steady state. It was found that in the shear rate range of 50 to 1,000 sec−1and temperature range of 100 to 160°C the viscosity of the cooked and compressed soy dough with 32%, 25% and 22% added moisture ranged from 10,000 to 500 poise and 20,000 to 200 poise and 20,000 to 1,000 poise respect

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00197.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1978.tb00198.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY