Food Analysis Laboratory Manual Second Edition

171 Pages·2010·3.36 MB·English

by  S. Suzanne Nielsen

Food Analysis
Laboratory Manual
Second Edition
For other titles published in this series, go to
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Food Analysis
Laboratory Manual
Second Edition
edited by
S. Suzanne Nielsen
Purdue University
West Lafayette, IN, USA
S. Suzanne Nielsen
Department of Food Science
Purdue University
West Lafayette IN
USA
ISBN 978-1-4419-1462-0 e-ISBN 978-1-4419-1463-7
DOI 10.1007/978-1-4419-1463-7
Springer New York Dordrecht Heidelberg London
Library of Congress Control Number: 2009943246
© Springer Science+Business Media, LLC 2010
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Contents
Preface and Acknowledgments vii 8 Complexometric Determination of Calcium 61
Notes on Calculations of Concentration ix
A EDTA Titrimetric Method for Testing
Hardness of Water 63
1 Nutrition Labeling Using a Computer B Test Strips for Water Hardness 65
Program 1
A Preparing Nutrition Labels for Sample 9 Iron Determination in Meat Using
Yogurt Formulas 3 Ferrozine Assay 69
B Adding New Ingredients to a Formula
and Determining How They Influence
the Nutrition Label 4 10 Sodium Determination Using Ion Selective
C An Example of Reverse Engineering Electrodes, Mohr Titration, and Test Strips 75
in Product Development 5
A Ion Selective Electrodes 77
B Mohr Titration 79
2 Assessment of Accuracy and Precision 9 C Quantab® Test Strips 81
11 Sodium and Potassium Determinations by Atomic
3 Determination of Moisture Content 17
Absorption Spectroscopy and Inductively Coupled
A Forced Draft Oven 19 Plasma-Atomic Emission Spectroscopy 87
B Vacuum Oven 21
C Microwave Drying Oven 22
D Rapid Moisture Analyzer 22 12 Standard Solutions and Titratable Acidity 95
E Toluene Distillation 22
A Preparation and Standardization
F Karl Fischer 23
of Base and Acid Solutions 97
G Near Infrared Analyzer 25
B Titratable Acidity and pH 99
4 Determination of Fat Content 29
13 Fat Characterization 103
A Soxhlet Method 31
A Saponification Value 105
B Goldfish Method 33
B Iodine Value 106
C Mojonnier Method 34
C Free Fatty Acid Value 108
D Babcock Method 35
D Peroxide Value 109
E Thin-Layer Chromatography Separation
of Simple Lipids 111
5 Protein Nitrogen Determination 39
A Kjeldahl Nitrogen Method 41
14 Fish Muscle Proteins: Extraction, Quantitation,
B Nitrogen Combustion Method 43
and Electrophoresis 115
6 Phenol-Sulfuric Acid Method for
Total Carbohydrates 47 15 Enzyme Analysis to Determine Glucose
Content 123
7 Vitamin C Determination by Indophenol
Method 55 16 Gliadin Detection in Food by Immunoassay 129
v
vi Contents
17 Examination of Foods for Extraneous Materials 137 19 Gas Chromatography 155
A Extraneous Matter in Soft Cheese 140 A Determination of Methanol and Higher
B Extraneous Matter in Jam 140 Alcohols In Wine by Gas Chromatography 157
C Extraneous Matter in Infant Food 141 B Preparation of Fatty Acid Methyl
D Extraneous Matter in Potato Chips 141 Esters (FAMEs), and Determination
E Extraneous Matter in Citrus Juice 142 of Fatty Acid Profile of Oils by Gas
Chromatography 159
18 High Performance Liquid Chromatography 145
20 Viscosity Measurement Using a Brookfield
A Determination of Caffeine in Beverages
Viscometer 165
by HPLC 147
B Solid-Phase Extraction and HPLC
Analysis of Anthocyanidins from Fruits 21 Calculation of CIE Color Specifications
and Vegetables 149 from Reflectance or Transmittance Spectra 171
Preface and Acknowledgments
This laboratory manual was written to accompany the of the reagents, because of the time limitations
textbook, Food Analysis, fourth edition. The laboratory for students in a laboratory session. The lists
exercises are tied closely to the text, and cover 20 of of supplies and equipment for experiments do
the 32 chapters in the textbook. Compared to the first not necessarily include those needed by the
edition of this laboratory manual, this second edition laboratory assistant in preparing reagents, etc.
contains two new experiments, and previous experi- for the laboratory session.
ments have been updated and corrected as appro- 4. The data and calculations section of the labo-
priate. Most of the laboratory exercises include the ratory exercises provides details on recording
following: background, reading assignment, objec- data and doing calculations. In requesting
tive, principle of method, chemicals (with CAS num- laboratory reports from students, instructors
ber and hazards), reagents, precautions and waste will need to specify if they require just sample
disposal, supplies, equipment, procedure, data and calculations or all calculations.
calculations, questions, and resource materials. 5. Students should be referred to the definitions
Instructors using these laboratory exercises on percent solutions and on converting parts
should note the following: per million solutions to other units of con-
centration as given in the notes that follow
1. It is recognized that the time and equipment
the preface.
available for teaching food analysis laboratory
sessions vary considerably between schools, Even though this is the second edition of this
as do the student numbers and their level in laboratory manual, there are sure to be inadvertent
school. Therefore, instructors may need to omissions and mistakes. I will very much appreciate
modify the laboratory procedures (e.g., num- receiving suggestions for revisions from instructors,
ber of samples analyzed; replicates) to fit including input from lab assistants and students.
their needs and situation. Some experiments I am grateful to the food analysis instructors
include numerous parts/methods, and it is identified in the text who provided complete labo-
not assumed that an instructor uses all parts ratory experiments or the materials to develop the
of the experiment as written. It may be logical experiments. The input I received from Dr. Charles
to have students work in pairs to make things Carpenter of Utah State University for the first edi-
go faster. Also, it may be logical to have some tion of this laboratory manual about the content of
students do one part of the experiment/one the experiments continued to be helpful for this sec-
type of sample, and other students to another ond edition. Likewise, my former graduate students
part of the experiment/type of sample. are thanked again for their help in working out and
2. The information on hazards and precautions in testing the experimental procedures written for the
use of the chemicals for each experiment is not first edition. For this second edition, I want to espe-
comprehensive, but should make students and cially thank my graduate student, Cynthia Machado,
a laboratory assistant aware of major concerns for her assistance and offering advice based on her
in handling and disposal of the chemicals. experience in serving as a teaching assistant for a
3. It is recommended in the text of the experi- Food Analysis laboratory course.
ments that a laboratory assistant prepare many
West Lafayette, IN S. Suzanne Nielsen
vii
Notes on Calculations
of Concentration
Definitions of Percent Solutions: µg mg mg
ppm= = =
Weight/Volume Percent (%, w/v) g 1000g L
= weight, in g of a solute, per 100 ml of solution
1000µg 1mg 0.001g
1000ppm= = =
Weight/Weight Percent (%, w/w) g g g
= weight, in g of a solute, per 100 g of solution
0.1g
Volume/Volume Percent (%, v/v) = =0.1%
100g
= volume, in ml of a solute, per 100 ml of solution
Concentration of minerals is expressed commonly
as parts per billion (ppb) or parts per million (ppm).
Parts per million is related to other units of measure as
follows:
ix
1
chapter
Nutrition Labeling Using
a Computer Program
Laboratory Developed by
Dr Lloyd E. Metzger,
Department of Dairy Science, South Dakota State University,
Brookings, SD, USA
S.S. Nielsen, Food Analysis Laboratory Manual, Food Science Texts Series, 1
DOI 10.1007/978-1-4419-1463-7_1, © Springer Science+Business Media, LLC 2010