摘要:

ABSTRACTA multivariate skimmilk extrusion process, designed to produce an acid coprecipitate was studied in terms of minimizing residual lactose, ash and fines. an experimental model system was utilized to simulate the extrusion process and evaluated using response surface methodology to assess the relationship between the responses (fines, residual lactose and minerals) and the process variables (concentration, pH, temperature, agitation, washing time and wash water ratio). Compromise optimum conditions were derived using the Generalized Distance Approach (GDA) and an Extended Response Surface Procedure (ERSP) which made use of the SAS RSREG procedure with and without constraints. the GDA procedure produced good results in terms of providing an optimum for a general acid casein process, while the ERSP allowed more extensive analysis of the data in terms of assessing specific processing conditions. Although more computing intensive, the ERSP conferred additional flexibility in determining optimal conditions for special situations such as extrusion processing. Both approaches are useful for process engineering, with the GDA being a more general tool while the ERSP is advantageous when the GDA procedure becomes limiting.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTA prototype fuzzy expert system was developed to predict the breakage susceptibility of corn for certain drying conditions and to provide recommendations for dryer control. the control decisions were based on predicted levels of breakage, drying conditions, and the recommendations of corn drying experts. Drying temperature, initial moisture content, equilibrium moisture content, and level of the wet product holding bin were used as the process information for providing recommendations for drying temperature and flow rate adjustment. Two example drying processes were tested. the results of the study showed that (1) the predicted corn breakage levels matched the experimental results and (2) the control recommendations by the system were consistent with domain experts.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTViscosity and density are two properties of fluids that are affected by temperature changes. the flow behavior of tomato sauce (7° and 14° Brix) in a tube viscometer was studied at varying concentrations of added particulates (2 and 5 wt%) at temperatures in the range of 70 to 95°C. the results indicate that the Power Law model described the flow behavior of the non‐Newtonian fluids better than the Casson model. the effects of temperature, concentration of carrier fluids and particulates on the flow behavior indices and viscosity was studied. the effect of temperature on the flow behavior index (n) and consistency index (K) were modeled as exponential relationships. the values of n and K for 7° Brix sauce ranged from 0.30 to 0.86 and 0.04 to 0.34, respectively. For the 14° Brix sauce these values were 0.27 to 0.53 and 0.20 to 0.60 respectively. the values of n decreased and K increased with increase in concentration of solids and particulates. the relative changes in K and n were lower for higher concentrations of solids and particulates. It was found that temperature had a greater effect on K than on n.The effects of temperature on viscosity was modeled as an Arrhenius type equation from which the activation energies were calculated. the combined effects of temperature, concentration of solids in the sauce and added particulates on apparent viscosity can be predicted by a nonlinear

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTA sensitivity analysis of a computer model, simulating heat transfer into particulate foods processed in a continuous aseptic system was conducted to determine how the model reacts to the variations in selected product and process input parameters depending on simulation types, namely, “Total”, “F0Hold” and “Hold Only”. Three major output variables, namely, holding tube required to destroy 6 D of Clostridium sporogenes (PA3679), destruction of thiamine and inactivation of peroxidase were selected for the sensitivity analysis. Theoretical results indicated that basically no difference between the “Total” system approach and the “F0Hold” approach was found on the model prediction. Particle size, particle thermal properties such as density and specific heat were the most sensitive parameters (within the range investigated) among product parameters which influence holding tube length required, thiamine and peroxidase retention while fluid properties such as fluid thermal conductivity and viscosity were less susceptible to affect the model prediction regardless of simulation types. Among process parameters, product flow rate and product initial temperature seemed to be the most critical parameters within the range covered in this study while rotor speed seemed to be one of the least critical parameters to influence the model prediction regardless

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1990.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY