ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01291.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTUtilization of proteins as new food products or as ingredients in formulated foods depends on the protein's ability to provide desired functional performance, in particular the ability to impart structure and texture. This review emphasizes the relevance of Theological testing in clarifying the physico‐chemical nature of the protein which permits prediction of functional behavior under a variety of conditions, as experienced in complex food systems. Emphasis has been placed on studies of protein (soy, egg albumen, caseinate, single cell, whey, gluten, rapeseed, gelatin) solutions and gels in which fundamental rheological principles have been applied. Appropriate rheological techniques are discussed as are factors which influence flow behavior since these provide the key to protein modification to impart desired functionality and hence effective utilizatio

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01292.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTMechanisms involved in the formation of three‐dimensional networks of globular proteins are discussed in general terms. Denaturation and aggregation of soy proteins under various conditions were studied. Differential scanning calorimetry was used in the denaturation, and turbidity measurements in the aggregation studies. Conditions favoring denaturation, such as high and low pH, had the opposite effect on aggregation. Salt was found to have a special effect on the behavior of soy proteins, suppressing aggregation as well as denaturation, probably due to its stabilizing influence on the quaternary structure. Viscometric studies of the progel state of soy protein gels showed that the onset of the progel is closely related to the denaturation process. Some commercial isolates were found to be completely denatured. Despite forming firm gels after cooling, they did not appear to have a progel stat

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01293.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTMechanical properties of foods are a direct consequence of micro‐structure which, in turn, results from an interaction of chemical composition and physical forces. In thermally‐extruded soy grits voids, caused by the escape of superheated steam as the textured vegetable protein product strikes the atmosphere, are thought to be responsible for the spongy, porous nature of the material. A breakdown of soy protein subunits followed by their reassembly into larger molecular weight aggregates, possibly via intermolecular amide bonds, may account for the formation of protein fibers that become aligned as they leave the extruder barrel. This structure persists after rehydration and imparts a desirable meat‐like texture to the product. By correlating mechanical properties to sensory analysis, an objective method has been developed for assessing the texture of extruded textured vegetable protein. This method has also proved useful in response surface investigations of the influence on texture of processing variables, including machine parameters and composition of the starting material. Other processes useful for producing textured vegetable proteins include freeze‐texturization and film formation and the formation of co‐e

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01294.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTSensory and instrumental tests employed for characterizing the texture of texturized plant proteins and their combinations with meat are reviewed. This methodology has borrowed heavily from that evolved for meat and, similarly to the studies on meat, has emphasized two parameters: toughness/tenderness and juiciness. Although it appears that this two‐parameter approach may be adequate, multiple‐parameter instrumental testing should be continued in order to prouide a data bank for the selection of the most accurate, reproducible and simplest measurements. It is suggested that researchers working in the commodity areas should make fuller use of the texture methodology literat

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01295.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTTexturization in an extruder occurs as a cereal, or oil seed, flour and water are mixed and cooked to form a dough, which is then shaped by forced flow through a die. Depending on the composition of the dough and the process conditions, the product may be dense, fibrous, or puffed. Under special conditions, expansion may be controlled to give a meat‐like texture.The mechanical elements of an extruder include the screw, barrel, and die. The operating parameters are: speed, power, imposed temperature, and flow rate. The dependent variables are: pressure build‐up, product temperature, and residence time distribution. The relationships among the design variables, operating parameters, and dependent variables are described by fluid‐dynamic equations developed in the polymer industry. These depend on several factors including the apparent viscosity of the cooking dough, which is a function of time and temperature hi

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01296.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTPrinciples of spinning edible protein fibers are discussed and the commercial development of the process is traced. Basic considerations involve structure requirements for a polymer to be fiber‐forming and the control of processing steps. Physical phenomena occurring during the spinning process are enumerated as well as structural changes, the exhibited physical properties and principle process variables. Recent modifications of the spinning process include melt‐spinning and the use of radio frequency or microwave heating for bringing the spinning solution up to the optimum forming temperat

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01297.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThis paper summarizes the work done by the authors (most of it published in Japan) and other researchers. The 11S protein is different from the 7S protein in that it makes much harder Tofu gels which are more sensitive to the softening effect of phytic acid and in which the S—S bonds appear to predominate. The US protein precipitates faster and forms larger aggregates. Its gelation characteristics suggest suitability as fish and meat extender. 11S gels have a higher water holding capacity than 7S gels, higher tensile values, higher hardness and expand more on heating. Similarly, 11S films are more elastic and have higher tensile values. It is pointed out that the functional properties of proteins may be controlled by regulating the binding forces through pH and additive

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01298.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA large number of commercial vegetable protein products based on soybeans and wheat were tested for functional properties and textural characteristics. Powder and paste products were tested for moisture, protein content, nitrogen solubility, whipping properties, emulsifying properties, water retention, consistency and textural parameters of heat‐set gels (hardness, cohesiueness, adhesiveness and breaking stress). Textured and fiberized products were tested for hardness, cohesiueness and resistance to shear‐compression both before and after heat treatment.With powder and paste products, foam stability, emulsifying properties and water retention were generally higher for soybean than for wheat products. Gel forming properties were higher for wheat products. For both raw materials, high correlations were found between different measures of gel hardness, between foam expansion and foam stability, and between emulsification capacity and emulsion stability. With textured products, high correlations were obtained between hardness and resistance to shear‐compression. Products based on wheat were harder and more difficult to shear. As compared to those distributed frozen, textured products distributed dry were significantly lower in cohesiueness following rehydr

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01299.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe growth of the textured vegetable protein industry has not kept pace with early predictions. High costs and marginal quality are among the factors retarding progress. Some of the technological gaps handicapping the industry are: lack of a process for preventing formation of off‐flavors by enzymes while maintaining protein functionality, lack of a low cost thermosetting binder, lack of a protein suitable for spinning, and the indigestibility of certain soybean fractions. These problems are discussed and new texturizing techniques are pointed out which show promise of overcoming or avoiding some of these problem

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1978.tb01300.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY