Human Foods and Their Nutritive Value

by Harry Snyder

Since 1897 instruction has been given at the University of Minnesota, College of Agriculture, on human foods and their nutritive value. With the development of the work, need has been felt for a text-book presenting in concise form the composition and physical properties of foods, and discussing some of the main factors which affect their nutritive value. To meet the need, this book has been prepared, primarily for the author's classroom. It aims to present some of the principles of human nutrition along with a study of the more common articles of food. It is believed that a better understanding of the subject of nutrition will suggest ways in which foods may be selected and utilized more intelligently, resulting not only in pecuniary saving, but also in greater efficiency of physical and mental effort.

Prominence is given in this work to those foods, as flour, bread, cereals, vegetables, meats, milk, dairy products, and fruits, that are most extensively used in the dietary, and to some of the physical, chemical, and bacteriological changes affecting digestibility and nutritive value which take place during their preparation for the table. Dietary studies, comparative cost and value of foods, rational feeding of men, and experiments and laboratory practice form features of the work. Some closely related topics, largely of a sanitary nature, as the effect upon food of household sanitation and storage, are also briefly discussed. References are given in case more extended information is desired on some of the subjects treated. While this book was prepared mainly for students who have taken a course in general chemistry, it has been the intention to present the topics in such a way as to be understood by the layman also.

This work completes a series of text-books undertaken by the author over ten years ago, dealing with agricultural and industrial subjects: "Chemistry of Plant and Animal Life," "Dairy Chemistry," "Soils and Fertilizers," and "Human Foods and their Nutritive Value." It has been the aim in preparing these books to avoid as far as possible repetition, but at the same time to make each work sufficiently complete to permit its use as a text independent of the series.

One of the greatest uses that science can serve is in its application to the household and the everyday affairs of life. Too little attention is generally bestowed upon the study of foods in schools and colleges, and the author sincerely hopes the time will soon come when more prominence will be given to this subject, which is the oldest, most important, most neglected, and least understood of any that have a direct bearing upon the welfare of man.

HARRY SNYDER.

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CONTENTS

CHAPTER I
General Composition of Foods	[1]
Water; Dry Matter; Variations in Weight of Foods;
Ash; Function of Ash in Plant Life; Organic Matter;
Products of Combustion of Organic Matter; Classification
of Organic Compounds; Non-nitrogenous Compounds;
Carbohydrates; Cellulose; Amount of Cellulose in Foods;
Crude Fiber; Starch; Microscopic Structure of Starch;
Dextrin; Food Value of Starch; Sugar; Pectose Substances;
Nitrogen-free-extract; Fats; Fuel Value of Fats;
Iodine Number of Fats; Glycerol Content of Fats; Ether
Extract and Crude Fat; Organic Acids; Dietetic Value
of Organic Acids; Essential Oils; Mixed Compounds;
Nutritive Value of Non-nitrogenous Compounds; Nitrogenous
Compounds; General Composition; Protein; Sub-divisions
of Proteins; Crude Protein; Food Value of
Protein; Albuminoids; Amids and Amines; Alkaloids;
General Relationship of the Nitrogenous Compounds.
CHAPTER II
Changes in Composition of Foods during Cooking and Preparation	[27]
Raw and Cooked Foods compared as to Composition;
Chemical Changes during Cooking; General Changes
affecting Cellulose, Starch, Sugar, Pectin Bodies, Fats,
Proteids; Effect of Chemical Changes on Digestibility;
Physical Changes during Cooking; Action of Heat on
Animal and Plant Tissues; Amount of Heat required for
Cooking; Bacteriological Changes; Insoluble Ferments;
Soluble Ferments; Bacterial Action Necessary in Preparation
of Some Foods; Injurious Bacterial Action; General
Relationship of Chemical, Physical, and Bacteriological
Changes; Esthetic Value of Foods; Color of Foods;
Natural and Artificial Colors; Conditions under which
Use of Chemicals in Preparation of Foods is Justifiable.
CHAPTER III
Vegetable Foods	[37]
General Composition; Potatoes; Chemical and Mechanical
Composition; Uses of Potatoes in Dietary; Sweet
Potatoes; Carrots; Parsnips; Cabbage; Cauliflower;
Beets; Cucumbers; Lettuce; Onions; Spinach; Asparagus;
Melons; Tomatoes; Sweet Corn; Eggplant;
Squash; Celery; Dietetic Value of Vegetables; Nutrient
Content of Vegetables; Sanitary Condition of Vegetables;
Miscellaneous Compounds in Vegetables; Canned Vegetables;
Edible Portion and Refuse of Vegetables.
CHAPTER IV
Fruits, Flavors and Extracts	[48]
General Composition; Food Value; Apples; Oranges;
Lemons; Grape Fruit; Strawberries; Grapes; Peaches;
Plums; Olives; Figs; Dried Fruits; Uses of Fruit in
the Dietary; Canning and Preservation of Fruits; Adulterated
Canned Fruits; Fruit Flavors and Extracts; Synthetic
Preparation of Flavors.
CHAPTER V
Sugars, Molasses, Syrup, Honey, and Confections	[58]
Composition of Sugars; Beet Sugar; Cane Sugar;
Manufacture of Sugar; Sulphur Dioxid and Indigo, Uses
of, in Sugar Manufacture; Commercial Grades of Sugar;
Sugar in the Dietary; Maple Sugar; Adulteration of
Sugar; Dextrose Sugars; Inversion of Sugars; Molasses;
Syrups; Adulteration of Molasses; Sorghum Syrup;
Maple Syrup; Analysis of Sugar; Adulteration of Syrups;
Honey; Confections; Coloring Matter in Candies; Coal
Tar Dyes; Saccharine.
CHAPTER VI
Legumes and Nuts	[71]
General Composition of Legumes; Beans; Digestibility
of Beans; Use of Beans in the Dietary; String
Beans; Peas; Canned Peas; Peanuts; General Composition
of Nuts; Chestnuts; The Hickory Nut; Almonds;
Pistachio; Cocoanuts; Uses of Nuts in the Dietary.
CHAPTER VII
Milk and Dairy Products	[80]
Importance in the Dietary; General Composition; Digestibility;
Sanitary Condition of Milk; Certified Milk;
Pasteurized Milk; Tyrotoxicon; Color of Milk; Souring
of Milk; Use of Preservatives in Milk; Condensed Milk;
Skim Milk; Cream; Buttermilk; Goat's Milk; Koumiss;
Prepared Milks; Human Milk; Adulteration of Milk;
Composition of Butter; Digestibility of Butter; Adulteration
of Butter; General Composition of Cheese;
Digestibility; Use in the Dietary; Cottage Cheese; Different
Kinds of Cheese; Adulteration of Cheese; Dairy
Products in the Dietary.
CHAPTER VIII
Meats and Animal Food Products	[98]
General Composition; Mineral Matter; Fat; Protein;
Non-nitrogenous Compounds; Why Meats vary in Composition;
Amides; Albuminoids; Taste and Flavor of
Meats; Alkaloidal Bodies in Meats; Ripening of Meats
in Cold Storage; Beef; Veal; Mutton; Pork; Lard;
Texture and Toughness of Meat; Influence of Cooking
upon the Composition of Meats; Beef Extracts; Miscellaneous
Meat Products; Pickled Meats; Saltpeter in
Meats; Smoked Meats; Poultry; Fish; Oysters, Fattening
of; Shell Fish; Eggs, General Composition; Digestibility
of Eggs; Use of Eggs in the Dietary; Canned
Meats, General Composition.
CHAPTER IX
Cereals	[121]
Preparation and Cost of Cereals; Various Grains used
in making Cereal Products; Cleanliness of; Corn Preparations;
Corn Flour; Use of Corn in Dietary; Corn Bread;
Oat Preparations; Cooking of Oatmeal; Wheat Preparations;
Flour Middlings; Breakfast Foods; Digestibility
of Wheat Preparations; Barley Preparations; Rice Preparations;
Predigested Foods; The Value of Cereals in the
Dietary; Phosphate Content of Cereals; Phosphorus Requirements
of a Ration; Mechanical Action of Cereals
upon Digestion; Cost and Nutritive Value of Cereals.
CHAPTER X
Wheat Flour	[133]
Use for Bread Making; Winter and Spring Wheat
Flours; Composition of Wheat and Flour; Roller Process
of Flour Milling; Grades of Flour; Types of Flour; Composition
of Flour; Graham and Entire Wheat Flours;
Composition of Wheat Offals; Aging and Curing of Flour;
Macaroni Flour; Color; Granulation; Capacity of Flour
to absorb Water; Physical Properties of Gluten; Gluten
as a Factor in Bread Making; Unsoundness; Comparative
Baking Tests; Bleaching; Adulteration of Flour; Nutritive
Value of Flour.
CHAPTER XI
Bread and Bread Making	[158]
Leavened and Unleavened Bread; Changes during
Bread Making; Loss of Dry Matter during Bread Making;
Action of Yeast; Compressed Yeast; Dry Yeast; Production
of Carbon Dioxid Gas and Alcohol; Production
of Soluble Carbohydrates; Production of Acids in Bread
Making; Volatile Compounds produced during Bread
Making; Behavior of Wheat Proteids in Bread Making;
Production of Volatile Nitrogenous Compounds; Oxidation
of Fat; Influence of the Addition of Wheat Starch
and Gluten to Flour; Composition of Bread; Use of
Skim Milk and Lard in Bread Making; Influence of
Warm and Cold Flours in Bread Making; Variations in
the Process of Bread Making; Digestibility of Bread;
Use of Graham and Entire Wheat in the Dietary; Mineral
Content of White Bread; Comparative Digestibility
of New and Old Bread; Different Kinds of Bread; Toast.
CHAPTER XII
Baking Powders	[186]
General Composition; Cream of Tartar Powders; Residue
from Cream of Tartar Baking Powders; Tartaric
Acid Powders; Phosphate Baking Powders; Mineral and
Organic Phosphates; Phosphate Residue; Alum Baking
Powders; Residue from Alum Baking Powders; Objections
urged against Alum Powders; Action of Baking
Powders and Yeast Compared; Keeping Qualities of
Baking Powders; Inspection of Baking Powders; Fillers;
Home-made Baking Powders.
CHAPTER XIII
Vinegar, Spices, and Condiments	[193]
Vinegar; Chemical Changes during Manufacture of
Vinegar; Ferment Action; Materials used in Preparation
of Vinegars; Characteristics of a Good Vinegar; Vinegar
Solids; Acidity of Vinegar; Different Kinds of Vinegars;
Standards of Purity; Adulteration of Vinegar; Characteristics
of Spices; Pepper; Cayenne; Mustard; Ginger;
Cinnamon and Cassia; Cloves; Allspice; Nutmeg; Adulteration
of Spices and Condiments; Essential Oils of;
Uses of Condiments in Preparation of Foods; Action of
Condiments upon Digestion; Condiments and Natural
Flavors.
CHAPTER XIV
Tea, Coffee, Chocolate, and Cocoa	[203]
Tea; Sources of Tea Supply; Composition of Tea;
Black Tea and Green Tea; Judging Teas; Adulteration
of Tea; Food Value and Physiological Properties of Tea;
Composition of Coffee; Adulteration of Coffee; Chicory
in Coffee; Glazing of Coffee; Cereal Coffee Substitutes;
Cocoa and Chocolate Preparations; Composition of Cocoa;
Chocolate; Cocoa Nibs; Plain Chocolate; Sweet Chocolate;
Cocoa Butter; Nutritive Value of Cocoa; Adulteration
of Chocolate and Cocoa; Comparative Composition
of Beverages.
CHAPTER XV
The Digestibility of Food	[214]
Digestibility, how Determined; Completeness and Ease
of Digestion Process; Example of Digestion Experiment;
Available Nutrients; Available Energy; Caloric Value of
Foods; Normal Digestion and Health; Digestibility of
Animal Foods; Digestibility of Vegetable Foods; Factors
influencing Digestion; Combination of Foods; Amount
of Food; Method of Preparation of Food; Mechanical
Condition of Foods; Mastication; Palatability of Foods;
Physiological Properties of Foods; Individuality; Psychological
Factors.
CHAPTER XVI
Comparative Cost and Value of Foods	[231]
Cost and Nutrient Content of Foods; How to compare
Two Foods as to Nutritive Value; Cheap Foods; Expensive
Foods; Nutrients Procurable for a Given Sum; Examples;
Comparing Nutritive Value of Common Foods
at Different Prices; Cost and Value of Nutrients.
CHAPTER XVII
Dietary Studies	[244]
Object of Dietary Studies; Wide and Narrow Rations;
Dietary Standards; Number of Meals per Day; Mixed
Dietary Desirable; Animal and Vegetable Foods;
Economy of Production; Food Habits; Underfed Families;
Cheap and Expensive Foods; Food Notions;
Dietary of Two Families Compared; Food in its Relation
to Mental and Physical Vigor; Dietary Studies in Public
Institutions.
CHAPTER XVIII
Rational Feeling of Man	[261]
Object; Human and Animal Feeding Compared; Standard
Rations; Why Tentative Dietary Standards; Amounts
of Food Consumed; Average Composition of Foods;
Variations in Composition of Foods; Example of a Ration;
Calculations of Balanced Rations; Requisites of a
Balanced Ration; Examples; Calculations of Rations for
Men at Different Kinds of Labor.
CHAPTER XIX
Water	[268]
Importance; Impurities in Water; Mineral Impurities;
Organic Impurities; Interpretation of a Water Analysis;
Natural Purification of Water; Water in Relation to
Health; Improvement of Waters; Boiling of Water; Filtration;
Purification of Water by Addition of Chemicals;
Ice; Rain Waters; Waters of High and Low Purity;
Chemical Changes which Organic Matter of Water Undergoes;
Bacterial Content of Water; Mineral Waters;
Materials for Softening Water; Uses of; Economic Value
of a Pure Water Supply.
CHAPTER XX
Food as Affected by Household Sanitation and Storage	[284]
Injurious Compounds in Foods; Nutrient Content and
Sanitary Condition of Food; Sources of Contamination
of Food; Unclean Ways of Handling Food; Sanitary Inspection
of Food; Infection from Impure Air; Storage
of Food in Cellars; Respiration of Vegetable Cells; Sunlight,
Pure Water, and Pure Air as Disinfectants; Foods
contaminated from Leaky Plumbing; Utensils for Storage
of Food; Contamination from Unclean Dishcloths; Refrigeration;
Chemical Changes that take Place in the
Refrigerator; Soil; Disposal of Kitchen Refuse; Germ
Diseases spread by Unsanitary Conditions around Dwellings
due to Contamination of Food; General Considerations;
Relation of Food to Health.
CHAPTER XXI
Laboratory Practice	[299]
Object of Laboratory Practice; Laboratory Note-book
and Suggestions for Laboratory Practice; List of Apparatus
Used; Photograph of Apparatus Used; Directions
for Weighing; Directions for Measuring; Use of Microscope;
Water in Flour; Water in Butter; Ash in Flour;
Nitric Acid Test for Nitrogenous Organic Matter; Acidity
of Lemons; Influence of Heat on Potato Starch Grains;
Influence of Yeast on Starch Grains; Mechanical Composition
of Potatoes; Pectose from Apples; Lemon Extract;
Vanilla Extract; Testing Olive Oil for Cotton Seed Oil;
Testing for Coal Tar Dyes; Determining the Per Cent of
Skin in Beans; Extraction of Fat from Peanuts; Microscopic
Examination of Milk; Formaldehyde in Cream or
Milk; Gelatine in Cream or Milk; Testing for Oleomargarine;
Testing for Watering or Skimming of Milk; Boric
Acid in Meat; Microscopic Examination of Cereal Starch
Grains; Identification of Commercial Cereals; Granulation
and Color of Flour; Capacity of Flour to absorb
Water; Acidity of Flour; Moist and Dry Gluten; Gliadin
from Flour; Bread-making Test; Microscopic Examination
of Yeast; Testing Baking Powders for Alum; Testing
Baking Powders for Phosphoric Acid; Testing Baking
Powders for Ammonia; Vinegar Solids; Specific Gravity
of Vinegar; Acidity of Vinegar; Deportment of Vinegar
with Reagents; Testing Mustard for Turmeric; Examination
of Tea Leaves; Action of Iron Compounds upon
Tannic Acid; Identification of Coffee Berries; Detecting
Chicory in Coffee; Comparative Amounts of Soap Necessary
with Hard and Soft Water; Solvent Action of Water
on Lead; Suspended Matter in Water; Organic Matter
in Water; Deposition of Lime by Boiling Water; Qualitative
Tests for Minerals in Water; Testing for Nitrites
in Water.
Review Questions	[323]
References	[350]
Index	[357]

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