Methods in Food Analysis

Methods in Food Analysis Applied to Food Products deals with the principles and the acquired tools of food analysis, emphasizing fruit and vegetable products. The book explains the suitability and limitations of the analytical procedures used for food products, from polarimetry and saccharimetry to colorimetry, spectrophotometry, viscosimetry, acidimetry, and alcoholometry. This volume is organized into 20 chapters and begins with an overview of sampling and preparation and preservation of sample. Under the physical methods, the principles of the more common procedures are discussed together with their application to the analysis of fruit and vegetable products. A brief account of the nature of the products is included. In presenting the chemical methods, the salient chemical properties of the constituent are first considered, focusing on those properties used in analysis, which is then followed by an outline of the chemistry of several of the available methods. Finally a detailed description of one of the methods, usually as applied to fruit and vegetable products, is explained. Some references to microanalytical, bioassay and bacteriological procedures are made. This book is intended for food technologists, chemists, and manufacturers; students; and researchers involved in quantitative analyses; organic and inorganic chemistry; and bacteriology.

I. Introduction

Outline of Contents

Sources of Information

References

II. Statistical Analysis, Errors, Expression of Results

Statistical Analysis

Errors

Expression of Results

References

III. Sampling: Preparation of Samples for Analysis, Preservation of Sample

Sampling

Preparation of Sample

Preservation of Samples

References

IV. Moisture Content and Total Solids

Properties of Water

Drying Methods

Vacuum-Oven Method

Other Drying Procedures

Distillation Procedures

Electrical Methods

Other Physical Methods

Chemical Methods

References

V. Ash Content and Ashing Procedures

Total Ash

Soluble and Insoluble Ash

Alkalinity of Ash

Conductometric Methods for Ash in Sugar Products

Special Dry Ashing Procedures

Ashing in Closed System in Presence of Oxygen

Wet Ashing

References

VI. Extraction Methods and Separation Processes

Proximate Chemical Analysis

Extraction Methods

Crude Fat or Ether Extract

Liquid-Liquid Extraction

Water-Insoluble Solids and Water-Soluble Solids

Crude Fiber

Alcohol-Insoluble Solids

Alcohol Precipitate

Clarification of Sugar Extracts

References

VII. Densimetric Methods

Measurement of Specific Gravity of Liquids

Measurement of Specific Gravity of Solids

Specific Gravity of Tomato Pulp

Specific Gravity of Oils

Specific Gravity of Sugar Products

The Grade of Canned Fruit

Rapid Determination of Total Fat

References

VIII. Refractometric Methods

Refractive Index

Refractive Constants

Applications of Refractive Index Measurements

Refractometers

Abbé Refractometer

Soluble Solids in Fruit Products

Total Solids in Tomato Pulp from Index of Refraction of Filtrate

Refractive Index of Oils and Fats

Oil Content

References

IX. Polarimetry and Saccharimetry

Specific Rotation

Mutarotation

Polarimetry

Saccharimeters

References

X. Colorimetry and Spectrophotometry

Absorption of Light

Emission of Light

Color Measurement: Colorimetry

Photoelectric Colorimetry

Spectrophotometry

Turbidimetry

Artificial Coloring Matter

References

XI. Potentiometric and Related Methods

Principles of Design and Use of Potentiometers

Oxidation-Reduction Potentials

Potentiometric Titrations

Polarographic Methods

Thermometry and Pyrometry

References

XII. pH and Buffer Capacity

Definition of pH

Buffers and Buffer Capacity

Application of pH and Buffer Capacity in Food Technology

Colorimetric Measurement of pH

Electrometric Determination of pH

References

XIII. Viscosimetric and Other Physical Methods

Viscosimetry

Plasticity and Plastometers

Gelometers

Tenderometers

Conductivity Measurements and Conductometric Analysis

Gas Analysis

References

XIV. Acidimetry

Organic Acids of Fruits and Vegetables and Other Foods

Total Organic Acids

Volatile Acids

Separation and Determination of Acids

Formic Acid

Lactic Acid

Tartaric Acid

References

XV. Alcoholometry

Ethyl Alcohol

Volumetric Dichromate Procedure

Physical Methods

Methyl Alcohol

Glycerin

References

XVI. Carbohydrates: Reducing Sugars

Occurrence

Chemical Methods for Reducing Sugars

Copper Reduction Procedures

Ferricyanide Reduction Methods

Direct Iodometric Methods

Identification and Determination of Sugars by Microorganisms

References

XVII. Carbohydrates: Sucrose and Starch

Sucrose

Starch

References

XVIII. Pectins and Pentosans

General Methods of Determining Pectin Content

Pentosans

References

XIX. Tannins

Methods Available for Analysis of Tannins

Loewenthal Titration

Colorimetric Procedure

Cinchonine Tannate Procedure

References

XX. Organic Nitrogenous Compounds

Total Organic Nitrogen

Nitrogen Fractionation

References

Index