摘要:

ABSTRACTImitation milks were prepared with different ratios of skim milk powder (SMP) and Recodan RS (R) as emulsifiers while keeping their total concentration constant. The ratio employed influenced the viscoelastic properties of the milks, as derived from creep compliance‐time studies, the electrophoretic mobility of the oil drops and the interfacial tension between the oil and aqueous phases. Optimum values of the viscoelastic parameters were obtained when the SMP/R ratio was between 4/1 and 8/1. Association occurs between the SMP and R under these conditions and stabilization of the flocculated oil drops is primarily by a steric mechanism. During storage of the milks the viscoelastic parameters initially increased due to continued growth of the flocculated oil drop structures, but subsequently the parameters decreased as drop coalescence became the predominant facto

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00304.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTReduced‐fat cheese (17% fat, 44% moisture) was considerably firmer and more elastic than full‐fat cheese (35% fat, 35% moisture), even though the moisture levels in the nonfat matter (MNFM) of the cheese were the same, at 54%. Electron microscopy and compositional analysis revealed about 30% more protein matrix in the reduced‐fat cheese. Apparently more of this matrix must be cut or deformed in sensorial and texture assessments. A practical implication is that MNFM should be slightly higher in the reduced‐fat cheese than in full‐fat cheese to achieve more similar texture.Homogenization of milk tended to increase the moisture content and decrease firmness and elasticity, but not markedly. The smaller fat globules, per se, did not apparently affect texture as measured in these experiments. Curd granule junctions were prominent in nonhomogenized‐milk cheese, because large fat globules were lost at the granule surfaces leaving protein‐dense junctions; those in homogenized‐milk cheese were less apparent because the protein‐dense areas, which resulted from the loss of small fat globules, were narrower.Sensory and textural parameters for firmness and elasticity were inter‐correlated. The Bite Test was more useful than Instron measurements of deformation (20%), apparently because the latter was markedly affected by a slight ope

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00305.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTGels were prepared from fresh and reconstituted skim milk (10–30% total solids) using glucono‐δ‐lactone as the acid precursor within the pH range of 4 to 6.Firmness of glucono‐δ‐lactone‐induced skim milk gels increased with (a) decrease in pH of skim milk having the same total solids content, (b) increase in total solids at a given pH, (c) pre‐heating skim milk to 90°C, and (d) adding glucono‐δ‐lactone at a higher temperature.Electron microscopy revealed that in condition (a) larger sizes of casein micelles (particles) were associated with a higher firmness whereas in conditions (b), (c), and (d) the increased firmness was correlated with decreased micelle sizes. The relation between rheological behavior and microstructure of glucono‐δ‐lactone‐induced skim milk gels was more dependent upon the micellar arrangement than upon the size and shape of the casein micelles. Conditions which led to large casein micelle clusters and chains in conditions (b), (c), and (d) resulted both in severe syneresis and in weaker gels.An unusual phenomenon was observed in skim milk gels made at pH 5.5, particularly at the lower total solids content (10%): the casein particles consisted of a solid core surrounded by an outer lining, 0.03–0.05 μm thick, which resembled a membrane‐line structure; there was a free annular space of 0.05 to 0.08 μm between the lining and the core. The existence of this structure was confirmed by thin‐section

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00306.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTCompression measurements on samples of Cheddar, Cheshire and Leicester cheeses with an Instron Universal Testing Machine indicate the presence of a yield point characteristic of crumbly foods. The force and nominal strain at the yield point were studied as a function of deformation rate, temperature and pre‐yield compression history. A recently proposed non‐linear viscoelastic model with a single fracture element fits individual compression curves, but the model has little predictive capabil

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00307.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA comparison of the published data on the flow behaviour of milk and cream at higher shear rates reveals conflicting results which can be explained partly by differences in experimental conditions. Among others, cold agglutination and churning effects appear to play a role. In the absence of these effects and at not very low shear rates, milk behaves as a Newtonian liquid. Excellent agreement is obtained between measured viscosity (η) as a function of fat content (øf) and theoretical relations between η; and the volume fraction of dispersed particles, but only if the volume occupied by the protein particles and sugar molecules in the milk is taken into accou

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00308.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Fundamentals of Food Canning Technology.J. M. Jackson, and B. M. Shinn.Meat Science, 3rd Edition. R. A. Lawrie.Chemical Aspects of Rice Grain Quality.Proceedings of the WorkshopPlant Pigments, Flavors and Textures: The Chemistry and Biochemistry of Selected Compounds.N. A. Michael Eskin.

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00309.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

GENERAL PRINCIPLES: Rheology of Xantham Gum. P. J. Whitcornbe* and C. W. Macosko.GENERAL PRINCIPLES: Relationship of Myofibril Fragmentation Index to Certain Chemical, Physical and Sensory Characteristics of Bovine Longissirnus Muscle. R. D. Culler, F. C. Parrish Jr.GENERAL PRINCIPLES: Characterization of the Stress Relaxation Curves of Solid Foods. M. Peleg.GENERAL PRINCIPLES: A Method for Measuring Strength and Extensibility of Bread Crumb. L. K. Dahle and and E. P. Montgomery.GENERAL PRINCIPLES: Microscopic Evaluation of Bread Fortified with Concentrated Plant Proteins. S. E. Fleming and F. W. Sosulski.GENERAL PRINCIPLES: Breadmaking Studied by Light and Transmission Electron Microscopy. D. B. Bechtel, Y. Pomeranz, and A. de Francisco.GENERAL PRINCIPLES: Note on a Method for Testing Gluten Strength. R. R. Matsuo.OBJECTIVE MEASUREMENTS: An Application of Electronic Paramagnetic Resonance: A Study of the Rheological Properties of Biological Systems. M. Le Pemp and D. Durand.OBJECTIVE MEASUREMENTS: An NMR Study of the Formation and Syneresis of Renneted Milk Gels. J. Lelievre and L. K. Creamer.OBJECTIVE MEASUREMENTS: The Effect of Shear Rate on the Viscosity of Solutions of Sodium Carboxymethylcellulose and K‐Carrageenan. A. M. Elfak, G. Pass and G. 0. Phillips.FACTORS AFFECTING TEXTURE: The Effect of Extractable Lipid on the Viscosity Characteristics of Corn and Wheat Starches. Madeline A. Melvin.FACTORS AFFECTING TEXTURE: A Brief Note on Certain Variations in the Viscosity of an Orange Juice Subjected to Various Treatments. F. Sauvageot and D. Simatos.FACTORS AFFECTING TEXTURE: Comparative Studies on Physicochemical and Baking Properties of Newly Harvested and Stored Indian Varieties of Wheat. V. Sudha Rao, Urmila K. Vakil and A.FACTORS AFFECTING TEXTURE: Relationship of Freezing Preservation Parameters to Texture‐Related StructuralFACTORS AFFECTING TEXTURE: A Simple Spread Test to Measure the Rheological Properties of Fermenting Dough. R. C. Hoseney, K. H. Hsu and R. C. Ju

ISSN:0022-4901    

DOI:10.1111/j.1745-4603.1980.tb00310.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY