An examination of the research on the availability of amino acids and proteins for nutrition and the effects of food processing on amino acid variability and quality.

From the Preface

The nutritional quality of cereal and oilseed proteins continues to be an important problem in human nutrition. Plant proteins are used freely and without prejudice in the formulation of animal rations, largely because of advances in knowledge of the amino acid requirements of domestic animals and recent progress in techniques of measure amino acid availability. Because less is known about the amino acid requirements of humans, the ability to predict the nutritive value of proteins for humans is less well developed. We hope that the contributions contained in this book will point to possible solutions to those problems.

Digestibility and Amino Acid Availability in Cereals and Oilseeds

1. Amino Acid Content as an Estimated of Protein Quality for Humans.

C. E. Bodwell

I. Introduction
II. Human Assays
III. Rat Assays
IV. Problems with the Use of Composition Data
V. Use of Amino Acid Composition Data
VI. Conclusions

2. Reducing Variability in Amino Acid Analysis.

John W. Finley

I. Introduction

A. Instrumentation

II. Sampling Procedures

A. Heterogeneous Samples
B. Drying Methods
C. Fat Extraction
D. Grinding
E. Liquid Samples
F. Soil Samples
G. Glassware
H. Water

III. Acid Hydrolysis for Amino Acid Profiles

A. Hydrogen Chloride
B. Vessels and Methods of Degassing
C. Nonprotein Material
D. A Benchmark Amino Acid Profile Method

IV. Extended Hydrolysis Time for Branched-Chain Amino Acids
V. Performic Acid Treatment and Hydrolysis for Sulfer Amino Acids
VI. Alkaline Hydrolysis for Determining Tryptophan
VII. Conclusion

3. Interactions Between Proteins and Constituents that Affect Protein Quality.

Pamela A. Anderson

I. Protein-Polyphenol Interactions
II. Protease Inhibitors
III. Phytic Acid

4. In Vitro Methods to Measure Sulfur Amino Acid Availability.

Samuel L. Mackenzie

I. Introduction
II. Oxidation and Availability
III. Chemical and Physical Methods

A. Hydrolytic Methods
B. Nonhydrolytic Methods

IV. Microbiological Methods

A. Tetrahymena pyriformis
B. Streptomyces zymogenes
C. Leuconostoc mesenteroides

V. Conclusions

5. Amino Acids in Cereals Proteins and Protein Fractions.

Okkyung Kim Chung and Yeshajahu Pomeranz

I. Introduction
II. Amino Acid Composition and Scores of Grain Proteins
III. Fractions of Cereal Proteins

A. Wheat
B. Barley
C. Rye
D. Triticale
E. Rice
F. Oats
G. Corn
G. Millet
I. Sorghum
J. Conclusions

IV. Summary and Suggestions for Future Work

6. Proteins in Developing Germinating Cereal Grains and Grain Fractions.

Okkyung Kim Chung and Yeshajahu Pomeranz

I. Introduction
II. Proteins in Developing and Germinating Grains

A. Grain Development and Maturation Stages
B. Effects of Yield, Fertilizers, and Protein Content on Nutritional Quality of Cereal Proteins
C. Effects of Germination on Cereal Protein Quality
D. Conclusion

III. High-Protein, High-Lysine Cereal Grains

A. Corn
B. Barley
C. Sorghum
D. Conclusions

IV. Proteins in Structural Parts and Milled Fractions of Cereal Grains

A. Weight and Protein Distribution in Structural Parts
B. Weight and Protein Distribution in Milled Fractions
C. Amino Acid Composition and Scores of Grain Fractions
D. Conclusions

V. Summary and Suggestions for Future Work

7. Functional and Nutritional Characteristics of Cereal Proteins.

Okkyung Kim Chung and Yeshajahu Pomeranz

I. Introduction
II. Functional and Nutritional Characteristics

A. Wheat
B. Rye and Triticale
C. Rice
D. Barley
E. Corn
F. Oats
G. Sorghum and Millets
H. Buckwheat
I. Conclusions

III. Summary and Suggestions for Future Work

8. Effects of Food Processing on Protein Digestibility and Amino Acid Availability.

R. F. Hurrell and P. A. Finot

I. Maillard Reactions
II. Protein-Polyphenol Reactions
III. Alkaline Treatments
IV. Reactions of Proteins with Oxidizing Lipids
V. Conclusions

9. In Vitro Methods to Predict Lysine Availability.

P. A. Finot and R. F. Hurrell

I. Introduction
II. Lysine Complexes Formed During Processing
III. Biological Availability

A. In Vitro Digestibility
B. Lysine Utilizability and Lysine Content

IV. Measurement of Reactive Lysine

A. The FDNB Methods
B. TNBS-Reactive Lysine
C. Reactive Lysine by Guanidination
D. Reactive Lysine by the Furosine Method
E. Reactive Lysine After Reduction by NaBH4
F. Reactive Lysine by Dye-Binding Procedure
G. Free Lysine
H. Microbiological Assays

V. In Vitro Digestibility
VI. Lysine Availability by Enzymatic Hydrolysis
VII. Conclusions

10. Direct Measurements of Amino Acid Digestibility in Swine.

T. D. Tanksley, Jr., and D. A. Knabe

I. Nitrogen and Amino Acid Digestibilities in Selected Cereal Grains
II. Nitrogen and Amino Acid Digestibilities in High-Protein Feedstuffs

A. Procedures
B. Results

III. The Road Ahead

11. Digestibility of Plant Proteins: Animal Studies.

Bjorn O. Eggum

I. Introduction
II. The Influence of Dietary Protein Level
III. Protein Amino Acid Digestibility
IV. Factors Affecting Protein Digestibility
V. Microbial Activity in the Digestive Tract
VI. Discussion and Conclusion

12. Absorption of Products of Protein Digestion.

Siamak A. Adibi

I. Introduction
II. Physiology of Digestion and Absorption

A. Gut Lumen Phase
B. Brush-Border Membrane Phase
C. Mucosal Cytoplasmic Phase

III. Nutritional Implications