Dairy technology [Recurso electrónico] : principles of milk properties and processes / P. Walstra ... [et al.].

Incluye referencias bibliográficas e índice.

Preface.--

Units and conversion factors.--

Part I. Milk.--

1. Composition, structure, and properties.--
1.1. Composition and structure.--
1.1.1. Principal components.--
1.1.2. Structure.--
1.2. Some properties.--
1.2.1. Density.--
1.2.2. Acidity.--
1.2.3. Redox potential.--
1.3. Variability.--
1.3.1. Sources of variation.--
1.3.2. Nature of the variation.--
1.3.3. Some important variables.--
1.4. Changes.--
Suggested literature.--

2. Milk components.--
2.1. Carbohydrates.--
2.1.1. Chemical properties of lactose.--
2.1.2. Physicochemical aspects of lactose.--
2.1.3. Lactic acid fermentation.--
2.2. Salts.--
2.2.1. Composition and distribution among the phases.--
2.2.2. Properties of the salt solution.--
2.2.3. Colloidal calcium phosphate.--
2.2.4. Changes in salts.--
2.3. Lipids.--
2.3.1. Composition.--
2.3.2. Some properties.--
2.3.3. Autoxidation.--
2.3.4. Crystallization.--
2.4. Proteins.--
2.4.1. Chemistry of proteins.--
2.4.2. Survey of milk proteins.--
2.4.3. Serum proteins.--
2.4.4. Casein.--
2.5. Enzymes.--
2.5.1. Enzyme activity.--
2.5.2. Some milk enzymes.--
2.5.3. Inactivation.--
2.6. Other components.--
2.6.1. Natural components.--
2.6.2. Contaminants.--
2.6.3. Radionuclides.--
2.6.4. Flavor compounds.--
Suggested literature.--

3. Colloidal particles of milk.--
3.1. Fat globules.--
3.1.1. Properties.--
3.1.2. Emulsion stability.--
3.1.3. Interactions with air bubbles.--
3.1.4. Creaming.--
3.1.5. Lipolysis.--
3.2. Casein micelles.--
3.2.1. Description.--
3.2.2. Changes.--
3.2.3. Colloidal stability.--
3.3. Physical properties.--
3.3.1. Optical properties.--
3.3.2. Viscosity (1).--
Suggested literature.--

4. Microbiology of milk.--
4.1. General aspects.--
4.1.1. Growth.--
4.1.2. Milk as a substrate for bacteria.--
4.2. Undesirable microorganisms.--
4.2.1. Spoilage microorganisms.--
4.2.2. Pathogenic microorganisms.--
4.3. Sources of contamination.--
4.3.1. Microorganisms present in the udder.--
4.3.2. Contamination during and after milking.--
4.4. Hygienic measures.--
4.4.1. Protection of the consumer against pathogenic microorganisms.--
4.4.2. Measures against spoilage organisms.--
Suggested literature.--

Part II. processes.--

5. General aspects.--
5.1. Introduction.--
5.2. Quality assurance.--
5.2.1. Concepts.--
5.2.2. Haccp.--
5.2.3. Quality assurance of raw milk.--
5.3. Milk storage and transport.--
5.3.1. Milk collection and reception.--
5.3.2. Milk storage.--
5.3.3. Transport of milk in the dairy.--
5.4. Standardizing.--
Suggested literature.--

6. Heat treatment.--
6.1. Objectives.--
6.2. Changes caused by heating.--
6.2.1. Overview of changes.--
6.2.2. Reactions of proteins.--
6.2.3. Reactions of lactose.--
6.2.4. Heat coagulation.--
6.3. Heating intensity.--
6.3.1. Processes of different intensity.--
6.3.2. Kinetic aspects.--
6.3.3. Thermobacteriology.--
6.3.4. Inactivation of enzymes.--
6.4. Methods of heating.--
6.4.1. Considerations.--
6.4.2. Equipment.--
6.4.3. Heat regeneration.--
6.4.4. Control.--
6.5. Appendix: heat transfer.--
Suggested literature.--

7. Centrifugation.--
Bactofugation.--

8. Homogenization.--
8.1. Objectives.--
8.2. Operation of the homogenizer.--
8.3. Theory of kolmogorov.--
8.4. Factors affecting the fat globule size.--
8.5. Surface layers.--
8.6. Stability.--
8.7. Homogenization clusters.--
8.8. Other effects of homogenization.--
8.9. Creaming.--
8.10. Other ways of working.--
Suggested literature.--

9. Concentration process.--
9.1. General aspects.--
9.1.1. Concentration of solutes.--
9.1.2. Water activity.--
9.1.3. Changes caused by concentrating.--
9.1.4. Reaction rates.--
9.2. Evaporating.--
9.3. Drying.--
9.3.1. Objectives.--
9.3.2. Drying methods.--
9.3.3. Atomization.--
9.3.4. Change of state of the drying air.--
9.3.5. Changes of state of the drying droplets.--
9.3.6. Two-stage drying.--
9.4. Membrane processes.--
9.4.1. Ultrafiltration.--
9.4.2. Reverse osmosis.--
9.4.3 electrodialysis.--
Suggested literature.--

10. Cooling and freezing.--
10.1. Cooling.--
10.2. Freezing.--
Suggested literature.--

11. Lactic fermentations.--
11.1. Lactic acid bacteria: types.--
11.1.1. Sugar metabolism.--
11.1.2. Type of lactic acid formed.--
11.1.3. Citrate metabolism.--
11.1.4. Production of acetaldehyde.--
11.1.5. Growth in milk and stimulation of growth.--
11.1.6. Proteolytic and lipolytic activities.--
11.1.7. Formation of polysaccharides.--
11.1.8. Plasmid-encoded properties.--
11.2. Acid production.--
11.3. Bacteriophages.--
11.3.1. Phage growth in the bacterial cell.--
11.3.2. Structure and function.--
11.3.3. Cell wall resistance and restriction.--
11.3.4. Inactivation.--
11.4. Starters.--
11.4.1. Composition.--
11.4.2. Properties.--
11.4.3. Shifts in the flora.--
11.4.4. Aspects of traditional starter manufacture —
11.4.5. Applications in the dairy industry.--
Suggested literature.--

12. Fouling, cleaning, and disinfection
12.1. Deposit formation.--

12.2. Cleaning.--

12.3. Disinfection.--
Suggested literature.--

13. Packing.--
Suggested literature.--

Part III. Milk products.--

14. Milk for liquid consumption.--
14.1. Pasteurized milk.--
14.1.1. Manufacture.--
14.1.2. Shelf life.--
14.1.3. Use of microfiltration.--
14.2. Sterilized milk.--
14.2.1. Description.--
14.2.2. Methods of manufacture.--
14.2.3. Shelf life.--
14.3. Flavor.--
14.4. Nutritive value.--
Suggested literature.--

15. Cream products.--
15.1. Sterilized cream.--
15.1.1. Manufacture.--
15.1.2. Heat stability.--
15.1.3. Stability in coffee.--
15.1.4. Clustering.--
15.2. Whipping cream.--
15.2.1. Desirable properties.--
15.2.2. Manufacture.--
15.2.3. The whipping process.--
15.2.4. Variables.--
15.3. Ice crean.--
15.3.1. Manufacture.--
15.3.2. Physical structure: formation and stability.--
15.3.3. Role of the various components.--
Suggested literature.--

16. Concentrated milks.--
16.1. Evaporated milk.--
16.1.1. Description.--
16.1.2. Manufacture.--
16.1.3. Organoleptic properties.--
16.1.4. Heat stability.--
16.1.5. Creaming.--
16.1.6. Age thickening and gelation.--
16.2. Sweetened condensed milk.--
16.2.1. Description.--
16.2.2. Manufacture.--
16.2.3. Microbial spoilage.--
16.2.4. Chemical deterioration.--
16.2.5. Lactose crystals.--
Suggested literature.--

17. Milk powder.--
17.1. Objectives.--
17.2. Manufacture.--
17.3. Hygienic aspects.--
17.3.1. Bacteria in the original milk.--
17.3.2. Growth during manufacture.--
17.3.3. Incidental contamination.--
17.3.4. Sampling and checking.--
17.4. Physical properties.--
17.5. Ease of dispersing; instant powder.--
17.6. Influence of process variables on product properties.--
17.6.1. Flavor.--
17.6.2. Wpn index.--
17.6.3. Insolubility.--
17.6.4. Specific volume.--
17.6.5. Free flowingness.--
17.6.6. Free fat content.--
17.6.7. Dispersibility.--
17.6.8. Stability.--
17.6.9. Conclusion.--
17.7. Deterioration.--
17.8. Other types of milk powder.--
17.9. Reconstituted products.--
Suggested literature.--

18. Protein preparations.--
18.1. Introduction.--
18.2. Manufacturing processes.--
18.2.1. Casein.--
18.2.2. Whey protein (wp) concentrates and wp complexes.--
18.2.3. Lactalbumin.--
18.2.4. Coprecipitation.--
18.2.5. Separation and modification.--
18.3. Functional properties.--
18.3.1. Solubility.--
18.3.2. Gelling properties.--
18.3.3. Swelling.--
18.3.4. Viscosity of solutions.--
18.3.5 emulsifier properties.--
18.3.6. Foaming.--
18.4. Other properties.--
Suggested literature.--

19. Butter.--
19.1. Description and manufacture.--
19.1.1. Description.--
19.1.2. Manufacturing scheme.--
19.1.3. The churning process.--
19.1.4. Working.--
19.2. Structure and properties.--
19.2.1. Microstructure.--
19.2.2. Consistency.--
19.2.3. Cold storage defects.--
19.3. Cultured butter from sweet cream.--
19.4. High-fat products.--
19.4.1. Anhydrous milk fat.--
19.4.2. Modification of milk fat.--
19.4.3. Recombined butter.--
19.4.4. Butter products with a low fat content.--
Suggested literature.--

20. Fermented milks.--
20.1. General aspects.--
20.1.1. Preservation.--
20.1.2. Nutritive value.--
20.2. Various types.--
20.2.1. Type of fermentation.--
20.2.2. Fat content.--
20.2.3. Concentration of the milk.--
20.2.4. Withdrawal of whey.--
20.2.5. Milk of various animal species.--
20.3. Yogurt.--
20.3.1. The yogurt bacteria.--
20.3.2. Manufacture; set and stirred yogurt.--
20.3.3. Physical properties.--
20.3.4. Flavor defects and shelf life.--
Suggested literature.--

Part IV. Cheese.--

21. Principles of cheese making.--
21.1. Introduction.--
21.2. Essential process steps.--
21.3. Clotting and syneresis.--
21.3.1. Chymosin.--
21.3.2. The enzyme-catalyzed reaction.--
21.3.3. The flocculation.--
21.3.4. The renneting time.--
21.3.5. Clotting of heated milk.--
21.3.6. Gel formation and syneresis.--
21.4. Chemical changes.--
Suggested literature.--

22. Process steps.--
22.1. Pretreatment of milk.--
22.1.1. Raw milk.--
22.1.2. Milk treatment.--
22.2. Curd making.--
22.2.1. Concentrating the protein.--
22.2.2. Curd treatment in the vat.--
22.3. Shaping and pressing.--
22.4. Salting.--
22.4.1. Mass transport during salting.--
22.4.2. Important variables.--
22.4.3. Distribution of salt and water after salting.--
22.4.4. Diffusion rate of other components.--
22.5. Storage and handling.--
22.5.1. Temperature.--
22.5.2. Air humidity and air velocity.--
22.5.3. Rind treatment.--
22.5.4. Packing.--
22.6. Standardization and yield.--
22.6.1. Standardization.--
22.6.2. Yield.--
Suggested literature.--

23. Cheese ripening and properties.--
23.1. Lactic fermentation.--
23.2. Enzyme sources.--
23.3. Proteolysis.--
23.3.1. Methods of characterization.--
23.3.2. Milk proteinases.--
23.3.3. Rennet enzymes.--
23.3.4. Enzymes of lactic acid bacteria.--
23.3.5. Enzymes of nonstarter organisms.--
23.3.6. Interaction between enzyme systems.--
23.4. Lipolysis.--
23.5. Development of flavor.--
23.5.1. Description.--
23.5.2. Changes during maturation.--
23.6. Development of texture.--
23.6.1. Structure.--
23.6.2. Consistency.--
23.7. Accelerated ripening.--
23.7.1. Increase of ripening temperature.--
23.7.2. Use of enzyme preparations.--
23.7.3. Increase of the number of lactic acid bacteria.--
23.7.4. Increasing the rate of lysis of starter cells.--
23.7.5. Addition of other bacteria.--
23.8. Nutritive value and safety.--
Suggested literature.--

24. Microbial defects.--
24.1. Coliform bacteria.--
24.2. Butyric acid bacteria.--
24.3. Lactobacilli.--
24.3.1. Common lactobacilli.--
24.3.2. Salt-tolerant lactobacilli.--
24.4. Heat-resistant septococci.--
24.5. Propionic acid bacteria.--
24.6. Organisms on the rind.--
24.7. Some other microbial defects.--
24.8. Establishing types of microbial defects with gas production.--
Suggested literature.--

25. Cheese varieties.--
25.1. Overview.--
25.1.1. Variations in manufacture.--
25.1.2. Types of cheese.--
25.2. Fresh cheese.--
25.2.1. Quarg.--
25.2.2. Cottage cheese.--
25.3. Gouda-type cheeses.--
25.3.1. Manufacture.--
25.3.2. Properties and defects.--
25.4. Swiss and pasta filata types.--
25.4.1. Emmentaler.--
25.4.2. Mozzarella.--
25.5. Cheddar-type cheeses.--
25.5.1. Manufacture.--
25.5.2. Properties.--
25.6. Cheeses with a specific flora.--
25.6.1. Soft cheese with a surface flora.--
25.6.2. Blue-veined cheese.--
25.7. Processed cheese.--
Suggested literature.

The primary theme of this book is to present the efficient transformation of milk into high-quality products. The changes in raw material and intermediate and final products and the interactions between product and process equipment are covered most prominently. Thus, it especially treats aspects that are specific for milk processing with the advanced dairy industry in mind. The stress is on principles of physical, chemical, enzymatic, and microbial transformations. Detailed manufacturing prescriptions or product specifications are not given, since they are widely variable.

Aimed at university food science and technology majors, the book is meant as a text, although it may also be useful as a work of reference. It is assumed that the reader is reasonably familiar with the general principles of food chemistry, microbiology, and physics and with elementary food engineering. In some instances, general aspects are briefly recalled. The book contains no references to the literature, but every chapter ends with suggestions for further reading. Most of the tables and figures were newly created, but for those that are reprinted a reference is given.

The book is made up of four parts. Part 1, “Milk”, discusses the chemistry, physics, and microbiology of milk. This provides the basis for understanding What happens during processing and storage. Part II, “Processes”, details the main unit operations applied in the manufacture of milk products. These are treated in some detail, including the influence of product and process variables on the result. Some general aspects of processing are also discussed. Some highly specific processes, such as churning, are discussed in product chapters. In Part III “Milk Products”, examples of the integration of knowledge of the raw material and of processing in the manufacture of products are discussed. The procedures needed to ensure consumer safety, product quality, and efficient processing are treated. The list of dairy products is almost endless and some groups have been selected because of their general importance or to illustrate relevant aspects. Finally, Part IV, “Cheese”, describes the processes and transformations (physical, biochemical, and microbial) in the manufacture and maturation of cheese. Here the processes are so specific and the interactions so intricate that a separate and integrated treatment is needed. This part starts with generic aspects and then discusses some specific groups of cheeses.

The nucleus of this book was a series of lecture notes (in Dutch) from Wageningen Agricultural University on dairy science and technology. Although meant for students, these lecture notes, of which several editions have been issued, were also frequently used by food technologists in practice. Hence, it was thought worthwhile to produce an international edition. The lecture notes were combined, reorganized, partly rewritten (to make them more internationally useful), and translated into English to result in one integrated textbook.

There was considerable overlap between part of the said lecture notes and the book by P. Walstra and R. Jenness, Dairy Chemistry and Physics (John Wiley and Sons, 1984). A similar overlap occurs between the latter book and this one, part of which can be seen as an update of Dairy Chemistry and Physics. We are greatly indebted to Wiley, and to Dr. R. Jenness, for allowing us to draw heavily on that book.

Several colleagues, too many to name them all, have been helpful in providing specific knowledge or in scrutinizing part of the book. Besides the important contributions by Dr. Jenness, we want to mention the late Professor E. A. Vos, who made the first versions of some of the lecture notes; Professor M. G. van den Berg, who commented on parts of the book; several colleagues from the Netherlands Institute for Research in Dairying (NIZO) who provided specific information; and, finally, all the people of our department who helped in various ways and especially for cooperating in all the research that was aimed at enhancing our understanding of the principles of dairy technology.

Al the authors of this book contributed to the original lecture notes and scrutinized parts of the draft for this book. Dr. T. J. Geurts made the English translations. The undersigned took responsibility for the final organization and editing of the book.



** Español **

El tema principal de este libro es presentar la transformación eficiente de la leche en productos de alta calidad. Los cambios en la materia prima y en los productos intermedios y finales, así como las interacciones entre el producto y el equipo de proceso, son tratados de forma destacada. Así, se tratan especialmente los aspectos específicos de la transformación de la leche pensando en la industria láctea avanzada. Se hace hincapié en los principios de las transformaciones físicas, químicas, enzimáticas y microbianas. No se dan prescripciones detalladas de fabricación ni especificaciones de productos, ya que son muy variables.

Dirigido a estudiantes universitarios de ciencia y tecnología de los alimentos, el libro está pensado como texto, aunque también puede ser útil como obra de consulta. Se supone que el lector está razonablemente familiarizado con los principios generales de la química, la microbiología y la física de los alimentos y con la ingeniería alimentaria elemental. En algunos casos, se recuerdan brevemente los aspectos generales. El libro no contiene referencias bibliográficas, pero cada capítulo finaliza con sugerencias de lecturas adicionales. La mayoría de las tablas y figuras son de nueva creación, pero para las que se reimprimen se da una referencia.

El libro consta de cuatro partes. La primera parte, "La leche", trata de la química, la física y la microbiología de la leche. Esto proporciona la base para entender lo que ocurre durante el procesamiento y el almacenamiento. La parte II, "Procesos", detalla las principales operaciones unitarias aplicadas en la fabricación de productos lácteos. Se tratan con cierto detalle, incluyendo la influencia de las variables del producto y del proceso en el resultado. También se comentan algunos aspectos generales de la transformación. Algunos procesos muy específicos, como el batido, se tratan en los capítulos dedicados a los productos. En la Parte III, "Productos lácteos", se analizan ejemplos de la integración de los conocimientos sobre la materia prima y el procesamiento en la fabricación de productos. Se tratan los procedimientos necesarios para garantizar la seguridad del consumidor, la calidad del producto y la eficacia de la elaboración. La lista de productos lácteos es casi interminable y se han seleccionado algunos grupos por su importancia general o para ilustrar aspectos relevantes. Por último, en la Parte IV, "El queso", se describen los procesos y transformaciones (físicas, bioquímicas y microbianas) en la fabricación y maduración del queso. Aquí los procesos son tan específicos y las interacciones tan intrincadas que es necesario un tratamiento separado e integrado. Esta parte comienza con los aspectos genéricos y luego analiza algunos grupos específicos de quesos.

El núcleo de este libro fue una serie de notas de clase (en holandés) de la Universidad Agrícola de Wageningen sobre ciencia y tecnología láctea. Aunque están destinados a los estudiantes, estos apuntes, de los que se han publicado varias ediciones, también son utilizados con frecuencia por los tecnólogos de los alimentos en la práctica. Por ello, se pensó que merecía la pena realizar una edición internacional. Los apuntes de clase se combinaron, se reorganizaron, se reescribieron en parte (para hacerlos más útiles a nivel internacional) y se tradujeron al inglés para dar lugar a un libro de texto integrado.

Una parte de estos apuntes se solapa con el libro de P. Walstra y R. Jenness, Dairy Chemistry and Physics (John Wiley and Sons, 1984). Un solapamiento similar se produce entre este último libro y el presente, parte del cual puede considerarse una actualización de Dairy Chemistry and Physics. Estamos en deuda con Wiley y con el Dr. R. Jenness por habernos permitido recurrir en gran medida a ese libro.

Varios expertos aportaron conocimientos específicos o analizaron parte del libro. Además hubo importantes contribuciones del Dr. Jenness, y el difunto profesor E. A. Vos, que hizo las primeras versiones de algunas de las notas de clase; el profesor M. G. van den Berg, comentó partes del libro; varios colegas del Instituto Holandés de Investigación Lechera (NIZO) aportaron información específica; y, por último, varias personas de nuestro departamento ayudaron de diversas maneras y, especialmente, por cooperar en todas las investigaciones destinadas a mejorar nuestra comprensión de los principios de la tecnología lechera.

Todos los autores de este libro contribuyeron a los apuntes originales de la conferencia y examinaron partes del borrador para este libro. El Dr. T. J. Geurts realizó las traducciones al inglés. Los autores se encargaron de la organización y edición final del libro.

Área de Ciencias de la Salud

Texto en inglés.