摘要:

ABSTRACTPower law models of dough sheeting are shown to be inadequate in predicting sheeting roll energy input to doughs. Empirical modification of the theoretical model yields a model which predicts energy input to a dough for different roll sizes. The model indicates that energy input will be different for different size rolls. It is suggested that this is a source of difficulty when scaling up from laboratory to plant.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00307.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTEngineers require quantitative models to design and optimize processes. In the food industry, these process models become very complex because of the unique physical/chemical characteristics and variability of the raw material. Furthermore, frequently data describing rates of reactions and/or changes in foods are generated by food scientists who are not thoroughly familiar with reaction models. Analysis of those data to obtain parameters for reaction models thus becomes critical. In this paper, calculating kinetic parameters from experimental data is examined, and suggestions are presented for determining reaction rates and temperature dependence.

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00308.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTMost of the methods proposed in literature for freezing time calculation require the previous knowledge of the enthalpy change and thermal conductivity of frozen materials. Ordinarily these properties are not easy to obtain, and often need a special approach depending on the process under consideration.This paper deals with a new and simple method that affords an estimation for Fluidized Bed Freezing of small food pieces (20‐40 mm) immersed in a cold fluidized bed of fine inert particles. Based upon Plank equation and temperature‐time recordings, the method more particularly yields the latent heat to be removed for bringing the product below the freezing poatt and the thermal conductivity of the matter in this final state. The associated percentage of water actually frozen during operation may be also determined.With the help of this technique properties have been determined for various fruits and vegetables (banana, carrot, potato, turnip and cucumber). The values that have been found agree well with literature data: latent heats correspond to the latent heat required to freeze 80% of the water in the products, and thermal conductivities lie between 1 and 2 W/m °C. Helpful correlations for Fluidized Bed Freezing time calculation are proposed that simply relate these properties to the total water content of mater

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00309.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe textural deterioration of cod muscle during frozen storage was investigated by objective measurement using the Instron Universal Testing Machine. The rates of texture change as a function of storage time revealed that the increased toughness and decreased cohesiveness could be described by a first‐order relationship. Higher storage temperatures resulted in more rapid rates of textural deterioration. Larger activation energy constants for toughness of cod muscle as compared to cohesiveness indicated that toughening was more temperature dependent than cohesiveness. The increased toughness and the decreased cohesiveness of frozen‐stored fish appeared to be related to the protein denaturation of the cod muscle and the loss of water‐holding capacity, respect

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00310.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00311.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe particle size analysis of maize, sorghum and millet under wet grinding conditions was studied with a burr grinding mill (the type commonly used in the locality). Some constants regarding particle size and size distribution of the wet ground products such as the distribution modulus, the size modulus, and the geometric mean diameter were determined.The ground material was wet seived in BS410 sieves with the aid of a dispersing agent, Calgon, which improved sieving, especially in the lower sieves.The results of the dried sieve fractions were plotted as cumulative percent by weight versus particle diameter on a log‐probability paper for the study of the particle size and size distribution characteristics. The geometric mean diameter (average particle size) of the ground product was observed to decrease with increase in moisture content, except that for maize which showed an initial rise before decrease. The size modulus, too, decreased with increase in moisture content but maize showord the usual deviation at the sian of soaking in water. The distribution modulus in maize and sorghum was seen to decrease with increase in moisture content but that of millet increased slightl

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00312.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1985.tb00306.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY