Theodore
P. Labuza, Ph.D.
Morse Alumni Distinguished
Teaching Professor of Food Science & Engineering
 tplabuza@umn.edu
136F ABLMS
1354 Eckles Avenue
St. Paul, MN 55108
612-624-9701
cell phone 612-669-7885
fax 651-483-3302
a
w
and Tg
resource page
Link to FScN 4111
Food
Chemistry Lecture material on water activity
Link
to FScN 4342
Properties of Water in
Food
Course on water activity and glass transition in foods
Go to aw
prediction programs
Go to list of isotherm
references
go to water activity
regulations
Go to isotherm papers
Go to Labuza water
activity papers and presentations
Go to other
presentations and papers
Go to aw and kinetics
courses links
Go to state diagrams
Go to Tg resources
Links
to water activity Instumentation
Decagon home page (dew
point devices)
note:contains
links to many useful pages of info on use of water
activity
Decagon aw discussion page
 
Rotronics (Impedance
cell)
NovaSina (impedance cell
UK Office)
CSIRO Water Activity Kit
Fax
and Phone contacts
Axair
AG - "Novasina Division" Talstrasse 35-37
CH-8808 Pfäffikon SZ
Tel.: +41-55-416 6111 Fax: +41-55-416 6262
Decagon Devices, Inc. P.O. Box 835, Pullman, Washington
99163 USA
Tel.: +1-509-332-2756 Fax: +1-509-332-5158
Laboratorymart.com 731 N. Labrea Ave., Suite 5 Los
Angeles, California, USA
Tel.: +1-323-931-1204
Fax: +1-323-931-1434
MT-Technologies Meßtechnik GmbH Waldhaus 1 D-86559
Adelzhausen
Tel.: +49-8208-9606-0
Fax: +49-8208-9606-99
\
Rotronic
Instrument Corp. 160 East Main Street, Huntington, NY
11743 USA
Tel: +1-516-4273898
Fax: +1-516-4273902
------------------------------------------------------------------------
General presentations on
water activity
Link
to FScN 4342
Properties of Water in
Food
Course on water activity and glass transition in foods
Also link to FScN 4111
Food Chemistry Lecture material
water activity and
isotherms (b/w pdf file)
water activity and
isotherms (color pdf file)
glass transition
applications (pdf)
glass transition
applications (color pdf)
DRINC
Web page
pdlab web page
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NEW
!!!
Institute
of Food Technologists, Annual Meeting
June
23-27, 2001
Ernest N Morial Convention Center
New Orleans, Lousina, USA
Molecular
Mobility in Foods :
Basic Science for Industrial Applications
Roos
(Univ Cork Ireland)
Molecular Mobility
-
Importance to Food Processing and Stability (350K pdf)
full page color  click here
3 slides per
page color click here
3 slides per
page B&W click here
Labuza
(U Minnesota)
Molecular Mobility and Reaction
Kinetics
2.1 meg pdf file Click here
Roudaut,
Champion and LeMeste (ENSBANA Univ. Dijon FR)
Molecular Mobility arond the Glass
Transition
pdf
file  Click here
Background papers on
water activity
Salts for water activity
control (pdf)
Sorption isotherm method
(pdf)
Review of aw and glass transition
(pdf)
Moisture Transfer in
Multidomain foods
Maillard Reaction
Shelf life testing 1
Shelf Life Testing 2
Diffusion
ISOPOW Water in Foods
Questions
References for Isotherms
and applications(pdf files)
theoretical Isotherms
aw prediction and isotherm properties
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Decagon
General application articles
fundamentals of aw
micro growth and aw
pharmaceutical
applications
water activity
regulations under FDA
Code
of Federal Regulations (CFR), Title 21 subpart references
to water activity.
In the definitions, §110.3(n), it says
"Safe-moisture level is a level of moisture low
enough to prevent the growth of undesirable
microorganisms in the finished product under the intended
conditions of manufacturing, storage, and
distribution." The maximum safe moisture level for a
food is based on its water activity (aw). An aw will be
considered safe for a food if adequate data are available
that demonstrate that the food at or below the given aw
will not support the growth of undesirable
microorganisms.
§110.3(r), Water activity (aw) is a measure of the free
moisture in a food and is the quotient of the water vapor
pressure of the substance divided by the vapor pressure
of pure water at the same temperature.
§110.80(b)(2) All food manufacturing, including
packaging and storage, shall be conducted under such
conditions and controls as are necessary to minimize the
potential for the growth of microorganisms, or for the
contamination of food. One way to comply with this
requirement is careful monitoring of physical factors
such as time, temperature humidity, aw, pH, pressure,
flow rate, and manufacturing operations…
§110.80(b)(4) Measures such as sterilizing, irradiating,
pasteurizing, freezing, refrigerating, controlling pH or
controlling aw that are taken to destroy or prevent the
growth of undesirable microorganisms, particularly those
of public health significance, shall be adequate under
the conditions of manufacture, handling, and distribution
to prevent food from being adulterated within the meaning
of the act.
§110.80 (b)(14) Food such as, but not limited to, dry
mixes, nuts, intermediate moisture food, and dehydrated
food, that relies on the control of aw for preventing the
growth of undesirable microorganisms shall be processed
to and maintained at a safe moisture level. Compliance
with this requirement may be accomplished by any
effective means, including employment of one or more of
the following practices:
(i) Monitoring the aw of food
(ii) Controlling the soluble solids-water ratio in
finished food
(iii) Protecting finished food from moisture pickup, by
the use of a moisture barrier or by other means, so that
the aw of the food does not increase to an unsafe level.
Reference: Title 21 CFR, Part 110. Good Manufacturing
Practice in Manufacturing, Packing, or Holding Human
Food. 4-1-96 Edition.
Campden R&D Water
Activity Measurement Guidebook
Description and order form ~ $60
Water activity in
pharmaceutics
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Water activity programs
Excel spreadsheet for mixed isotherm
calculation from Micha Peleg (for free)
Click to download Description of above
spreadsheet
Ron Webb's Water Analyzer series
(download trial program)
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The following
files are in hex format so need to be expanded with
Stuffit unless your browser is set to do this
automatically
In addition they are written for use on Mac's only and
require Hypercard player and the home stack, both
available below. Below each file are some example data
sets and at the bottom is a 103 page manual for the
programs.
Labuza-Nelson BET and
GAB isotherm determination
initial moisture
calculation example
isotherm from raw data
(weight gain)
isotherm from aw vs
moisture data
Clausius Clapeyron effect on isotherms
three temperatures
example
Film
Moisture permeability
example film permeance
Moisture Gain in permeable packaging
GAB and Linear
calculation
water activity calculation from
isotherms(GAB),
Norrish and Ross Equations
Example aw calculation
Labuza Nelson Reaction Order
and Activation Energy Determination
Hypercard Player
Hypercard Home Stack
Labuza-Nelson Moisture
and Kinetics Manual
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Glass Transition
Resources
Papers
Glass transition
measurement TP Labuza (pdf)
Glass transition
applications TP Labuza (pdf)
Tg
diagrams with data
Compilation
paper 1992 with data and figure (click
to retrieve below)
Starch
Pregelatinized wheat starch
Native wheat starch
Rice starch
Flour and Flour Proteins
Wheat gluten
Hard Wheat Flour
Soft Wheat Flour
Hard Wheat Gluten
Soft Wheat Gluten
Glutenin
Heat-Treated Gluten
Maltodextrins
Maltodextrin 5
Maltodextrin 15
Maltodextrin 20
Maltodextrin 25
Maltodextrin 36
Sugars
Lactose
Sucrose
Sucrose/Amioca
Maltose
Glucose
Sucrose/Fructose Mixtures
Fructose/Glucose Mixtures
fructose/sucrose Mixtures
Sodium Carboxymethyl Cellulose
Xanthan Gum
Multi-component Model Systems
Lactose/CMC/Trehalose/Xylose/Lysine
Lactose/Amioca/Lysine
Lactose/CMC/Xylose/Lysine
PVP/Glucose/Glycine
Vegetables
Soybean Seeds
Horseradish Roots
Cabbage
Carrots
Potatoes
Corn Embryos
Strawberry Powder
Table of dry Tg values for many foods
Click here to dowload
this as a word file 
click
Click here to get as a pdf file
click
State Diagrams (with data) - under development
download
sucrose property data click here
If
you have created a state diagram please submit it to me
and we will build this site Try to do it excell so I can
convert to bin-hex and then make available to everyone.
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Other Useful Courses
Information
...
 .
 Click data graph
at left to link to EU physical
properties database
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DOWNLOAD
Power Point Presentations
Research Papers and Book Chapters
Practical Aspects of
Isotherm Measurement and Use L. Bell and T Labuza AACC
Egan Press 81/2;" x 11" perfect bound;
123 pages; 38 figures ISBN 1-891127-18-7
$79 US; 79 EUROS Item No. 27187
Shelf
Life Book
SHELF-LIFE
DATING OF FOODS, T.P. Labuza. 1982. 500 Pages. Cat. No.
3220. ISBN 0-917678-14-1. $85.00. Reviews the basic
technology and scientific capability that would be
applicable for setting open-dating regulations for
processed foods.
www.foodscipress.com/orderinfo2.htm
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