Decagon Devices, Inc. ersion 7 LITE W xpublications.decagon.com/Manuals/10252_AquaLab...
30
AquaLab LITE Index 54 W Warranty 2 Warranty card 2 Water activity AquaLab Lite and 4 definition 4, 36 effect on food 4, 36 of verification standards 21 stability diagram 37 theory 36 Water content definition 36 methods for determining 36 vs. water activity 36, 40 Water potential factors in determining 39 matric effects 40 osmotic effects 39 relation to water activity 38 LITE Operator’s Manual Version 7 Decagon Devices, Inc.
Transcript of Decagon Devices, Inc. ersion 7 LITE W xpublications.decagon.com/Manuals/10252_AquaLab...
Aqu
aLab
LIT
EIn
dex
54
W War
ran
ty 2
War
ran
ty c
ard
2W
ater
act
ivit
yA
quaL
ab L
ite
and
4de
fini
tion
4, 3
6ef
fect
on
food
4, 3
6of
ver
ific
atio
n st
anda
rds
21st
abil
ity
diag
ram
37
theo
ry 3
6W
ater
con
ten
tde
fini
tion
36
met
hods
for
det
erm
inin
g 36
vs. w
ater
act
ivit
y 36
, 40
Wat
er p
oten
tial
fact
ors
in d
eter
min
ing
39m
atri
c ef
fect
s 40
osm
otic
eff
ects
39
rela
tion
to w
ater
act
ivit
y 38
LITE
Op
erat
or’s
Man
ual
Ver
sion
7
Dec
agon
Dev
ices
, In
c.
AquaLab LITE
Index
53
food quality and safety 43m
eat and seafood 44m
icrobiology 43pharm
aceuticals 47w
ater activity theory 42R
elative hu
mid
ity 4R
epaircosts 34
Rep
aircosts 36instructions for 33
SSam
ple cu
ps 14
Sam
ple p
reparation
14S
eller’s liability 3
Sorp
tion isoth
erms
relating water activity to w
ater content 40
TTech
nical su
pp
ort 2T
emp
erature
effects on water activity 38
Th
eoryw
ater activity 42T
urn
ing on
the in
strum
ent 8
VVolatiles
effect on sensor 26
Decagon
Devices, In
c.2365 N
E H
opkins Court
Pullm
an WA
99163(509) 332-5601
fax: (509) 332-5158w
ww
.aqualab.comsales@
aqualab.comsupport@
aqualab.com
Trad
emark
sA
quaLab L
ITE
is a registered trademark of
Decagon D
evices, Inc.
© 2007-2012 D
ecagon Devices, Inc.
Aqu
aLab
LIT
EIn
dex
52
E Em
ail 2
E-m
ail a
dd
ress
2E
thyl
alc
ohol
26
F Fax
2F
eatu
res
7F
urt
her
rea
din
g 42
L Lan
guag
e fu
nct
ion
12
Loa
ner
ser
vice
35
M Man
ual
abou
t 1M
enu
s 10
O On
turn
ing
on th
e in
stru
men
t 8O
smot
ic e
ffec
ts 3
9
P Ph
arm
aceu
tica
ls 4
7P
hon
e 2
R Ref
eren
ces
42
Aqu
aLab
LIT
ETa
ble
of C
onte
nts
i
Tab
le o
f Co
nten
ts
1. I
ntro
duc
tio
n .
. . .
. . .
. . .
. . .
. . .
. . .
. 1
Ab
out
this
Man
ual
. .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
1N
ote
to o
ur
Aq
uaL
ab L
ITE
Use
rs
. . .
. . .
. . .
. 1
Cu
stom
er S
up
por
t .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. 2
War
ran
ty
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
2S
elle
r’s
Lia
bil
ity
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. 3
2. A
bo
ut t
he A
qua
Lab
LIT
E .
. . .
. . .
. . .
4A
qu
aLab
LIT
E a
nd
wat
er a
ctiv
ity
. . .
. . .
. . .
. 4
How
Aq
uaL
ab L
ITE
wor
ks
. . .
. . .
. . .
. . .
. . .
4A
ccu
racy
. .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . 5
Sp
ecif
icat
ion
s .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . 5
Ou
t of
th
e B
ox
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . 6
Fea
ture
s . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
7
3. G
etti
ng S
tart
ed .
. . .
. . .
. . .
. . .
. . .
. 8
Pre
par
ing
for
Op
erat
ion
. .
. . .
. . .
. . .
. . .
. . .
. 8
Tu
rnin
g th
e A
qu
aLab
LIT
E o
n
. . .
. . .
. . .
. . .
8T
he
Men
us
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. 10
“Cal
ibra
te”
Fun
ctio
n .
. . .
. . .
. . .
. . .
. . .
. . 1
0“L
angu
age”
Fun
ctio
n . .
. . .
. . .
. . .
. . .
. . .
. 12
“Con
tras
t” F
unct
ion
. . .
. . .
. . .
. . .
. . .
. . .
. 12
“Dia
gnos
tics
” F
unct
ion
. . .
. . .
. . .
. . .
. . .
. 13
“Abo
ut”
Fun
ctio
n . .
. . .
. . .
. . .
. . .
. . .
. . .
. 13
4. A
qua
Lab
LIT
E O
per
ati
on
. . .
. . .
. . .
14S
amp
le P
rep
arat
ion
an
d I
nse
rtio
n .
. . .
. . .
. .
14S
amp
le P
rep
arat
ion
. .
. . .
. . .
. . .
. . .
. . .
. . .
. 14
Sam
ple
In
sert
ion
. .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
16
AquaLab LITE
Index
51
Index
AAccu
racy 5A
qu
aLab
and chilled mirror dew
point technique 4theory 36
Au
tocalibrate function 24
CCalib
ratem
enu 10C
alibration
auto function 24defaults setting 24
CE
comp
liance 50
Com
pon
ents
shipped items w
ith system 6
Com
pu
ter interface 28
Con
nectin
g to a comp
uter 28
Cu
stomer su
pp
ort 2
DDeclaration
of Con
formity 50
Defau
ltssetting in calibration 24
Diagn
ostics 13
AquaLab LITE
Table of Contents
ii
Sam
pling Cautions . . . . . . . . . . . . . . . . . . . . 18
Tak
ing M
easurem
ents . . . . . . . . . . . . . . . . . . . 19
Tu
rnin
g the A
qu
aLab
LIT
E off . . . . . . . . . . . 20
Calib
ration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Calibration S
tandards . . . . . . . . . . . . . . . . . . 21H
ow to V
erify if Calibration A
djustment
Is Needed . . . . . . . . . . . . . . . . . . . . . . . . 22
Adjusting the C
alibration . . . . . . . . . . . . . . . 23S
amp
ling P
recaution
s . . . . . . . . . . . . . . . . . . . 26A
qu
aLab
LIT
E an
d T
emp
erature . . . . . . . . . 27
5. Co
mp
uter Interface . . . . . . . . . . . . .2
8A
qu
aLin
k 4 S
oftware . . . . . . . . . . . . . . . . . . . . 28
Usin
g a Com
mu
nication
Program
. . . . . . . . . 28
6. C
leaning
and
Ma
intenance . . . . . . .3
0C
leanin
g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30M
ainten
ance . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Sensor F
ilter Cleaning/R
eplacement . . . . . . 31
7.R
epa
ir Instructions . . . . . . . . . . . . .3
3S
hip
pin
g Direction
s: . . . . . . . . . . . . . . . . . . . . 33R
epair C
osts . . . . . . . . . . . . . . . . . . . . . . . . . . . 34L
oaner S
ervice . . . . . . . . . . . . . . . . . . . . . . . . . 35
8.Theory
: Wa
ter Activ
ity in Pro
ducts 3
6W
ater Con
tent . . . . . . . . . . . . . . . . . . . . . . . . . 36
Water A
ctivity . . . . . . . . . . . . . . . . . . . . . . . . . 36E
ffect of Tem
peratu
re on W
ater Activity . . . 38
Water P
otential . . . . . . . . . . . . . . . . . . . . . . . . 38
Factors in
Determ
inin
g Water P
otential . . . . 39
Osm
otic Effects . . . . . . . . . . . . . . . . . . . . . . 39
Matrix E
ffects . . . . . . . . . . . . . . . . . . . . . . . 40
Aqu
aLab
LIT
ED
ecla
ratio
n of
Con
form
ity
50
Dec
lara
tion
of
Con
form
ity
App
lica
tion
of
Cou
ncil
2004/108
/EC
Dir
ecti
ve:
Stan
dard
s to
whi
ch
conf
orm
ity
is d
ecla
red:
EN61326-1:2013
Man
ufac
ture
r’s
Nam
e:D
ecag
on D
evic
es, I
nc.
2365
NE
Hop
kins
Cou
rtP
ullm
an, W
A 9
9163
US
A
Type
of
Equ
ipm
ent:
Aqu
aLab
LIT
E w
ater
acti
vity
met
er.
Mod
el N
umbe
r:
Yea
r of
Fir
st M
anuf
actu
re:
2004
Thi
s is
to
cert
ify
that
the
Aqu
aLab
LIT
E w
ater
act
ivit
y m
eter
, man
ufac
ture
d by
Dec
agon
Dev
ices
, Inc
., a
corp
ora-
tion
bas
ed in
Pul
lman
, Was
hing
ton,
US
A m
eets
or
exce
eds
the
stan
dard
s fo
r C
E c
ompl
ianc
e as
per
the
Cou
ncil
Dir
ec-
tive
s no
ted
abov
e. A
ll in
stru
men
ts a
re b
uilt
at t
he f
acto
ry a
t D
ecag
on
and
pert
inen
t te
stin
g do
cum
enta
tion
is
fr
eely
av
aila
ble
for
veri
fica
tion
. T
his
cert
ific
atio
n ap
plie
s to
all
Aqu
aLab
LIT
E m
odel
s.
Aqu
aLab
LIT
ETa
ble
of C
onte
nts
iii
Sor
pti
on I
soth
erm
s .
. . .
. . .
. . .
. . .
. . .
. . .
. . 4
0R
elat
ing
Wat
er A
ctiv
ity
to W
ater
Con
tent
.
40
9. F
urth
er R
ead
ing
. .
. . .
. . .
. . .
. . .
.4
2W
ater
Act
ivit
y T
heo
ry a
nd
Mea
sure
men
t . .
. 42
Foo
d Q
ual
ity
and
Saf
ety
. . .
. . .
. . .
. . .
. . .
. .
43W
ater
Act
ivit
y an
d M
icro
bio
logy
. .
. . .
. . .
. . 4
3W
ater
Act
ivit
y in
Foo
ds
. . .
. . .
. . .
. . .
. . .
. .
44M
eat a
nd S
eafo
od
. . .
. . .
. . .
. . .
. . .
. . .
. . 4
4D
airy
Pro
duct
s . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
45
Fru
its
and
Veg
etab
les
. . .
. . .
. . .
. . .
. . .
. . .
45B
aked
Goo
ds a
nd C
erea
ls
. . .
. . .
. . .
. . .
. . 4
6P
har
mac
euti
cals
/Cos
met
ics
. . .
. . .
. . .
. . .
. . .
47M
isce
llan
eou
s . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
48
Dec
lara
tio
n o
f Co
nfo
rmit
y .
. . .
. . .
. .5
0
Ind
ex .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. . .
. 51
AquaLab LITE
9.Further Reading
49
Fernandez-S
alguero J., R. G
ómez, and M
.A. C
armona.
(1993). Water activity in selected high-m
oisture foods. Journal of F
ood Com
position and Analysis. 6:364-369.
AquaLab LITE
Table of Contents
iv
Aqu
aLab
LIT
E9.
Fur
ther
Rea
ding
48
Pra
ctic
e. K
abar
a, J
.J.
and
D.S
. O
rth
(ed.
) M
arce
l D
ek-
ker,
pp. 4
5-73
.H
agem
an, M
.J. (
1988
). T
he r
ole
of m
oist
ure
in p
rote
in s
ta-
bili
ty.
Dru
g D
evel
opm
ent
and
Indu
stri
al
Pha
rmac
y.
14(1
4):2
047-
2070
.H
eide
man
n, D
.R.
and
P.J.
Jar
osz.
(19
91).
Per
form
ulat
ion
stud
ies
invo
lvin
g m
oist
ure
upta
ke
in
soli
d do
sage
fo
rms.
Pha
rmac
euti
cal R
esea
rch.
8(3
):29
2-29
7.F
ried
el, R
.R. a
nd A
.M. C
unde
ll. (
1998
). T
he a
ppli
cati
on o
f w
ater
ac
tivi
ty
mea
sure
men
t to
th
e m
icro
biol
ogic
al
attr
ibut
es t
esti
ng o
f no
n-st
eril
e ov
er-t
he-c
ount
er d
rug
prod
ucts
. Pha
rmac
opei
al F
orum
. 24(
2):6
087-
6090
.K
ontn
y, M
.J. (
1988
). D
istr
ibut
ion
of w
ater
in s
olid
pha
rma-
ceut
ical
sy
stem
s.
Dru
g D
evel
opm
ent
and
Indu
stri
al
Pha
rmac
y. 1
4(14
):19
91-2
027.
Zog
rafi
, G
. (1
988)
. St
ates
of
wat
er a
ssoc
iate
d w
ith
soli
ds.
Dru
g D
evel
opm
ent
and
Indu
stri
al
Pha
rmac
y.
14(1
4):1
905-
1926
.
Mis
cella
neo
usB
ell,
L.N
. an
d T.
P. L
abuz
a. (
1992
). C
ompo
siti
onal
inf
lu-
ence
on
the
pH o
f re
duce
d-m
oist
ure
solu
tion
s. J
ourn
al
of F
ood
Sci
ence
. 57:
732-
734.
Bel
l, L
.N.
and
T.P.
Lab
uza.
(19
94).
Inf
luen
ce o
f th
e lo
w-
moi
stur
e st
ate
on p
H a
nd i
ts i
mpl
icat
ion
for
reac
tion
ki
neti
cs. J
ourn
al o
f F
ood
Eng
inee
ring
. 22:
291-
312.
Bel
l, L
.N.
(199
5).
Kin
etic
s of
non
-enz
ymat
ic b
row
ning
in
amor
phou
s so
lid
syst
ems:
Dis
tingu
ishi
ng t
he e
ffec
ts o
f w
ater
act
ivit
y an
d th
e gl
ass
tran
siti
on.
Foo
d R
esea
rch
Inte
rnat
iona
l. 28
:591
-597
.B
rake
, N.C
. and
O.R
. Fen
nem
a. (
1993
). E
dibl
e co
atin
gs t
o in
hibi
t lip
id m
igra
tion
in a
con
fect
ione
ry p
rodu
ct. J
our-
nal o
f F
ood
Sci
ence
. 58:
1422
-142
5.
Aqu
aLab
LIT
E1.
Intr
oduc
tion
1
1.In
tro
duc
tio
n
Wel
com
e to
Dec
agon
's A
quaL
ab L
ITE
inte
rmed
iate
ben
ch-
top
wat
er a
ctiv
ity
met
er.
The
Aqu
aLab
LIT
E i
s a
noth
er
qual
ity
wat
er
acti
vity
m
eter
fr
om
Dec
agon
: th
e w
orld
le
ader
in
wat
er a
ctiv
ity
tech
nolo
gy.
Aqu
aLab
LIT
E c
om-
bine
s te
chno
logy
fro
m A
quaL
ab,
the
wor
ld's
fas
test
and
m
ost
accu
rate
wat
er a
ctiv
ity
met
er,
and
the
ultr
a-co
mpa
ct
Paw
kit
into
thi
s m
idra
nge
inst
rum
ent.
Aqu
aLab
LIT
E i
s ea
sy t
o us
e an
d pr
ovid
es a
ccur
ate
and
tim
ely
resu
lts.
We
hope
yo
u fi
nd
this
m
anua
l in
form
ativ
e an
d he
lpfu
l in
un
ders
tand
ing
how
to
max
imiz
e th
e ca
pabi
litie
s of
you
r A
quaL
ab L
ITE
. A
ll A
quaL
ab m
odel
s ar
e su
ppor
ted
by a
n ex
peri
ence
d st
aff.
Whe
n yo
u bu
y an
Aqu
aLab
LIT
E f
rom
us
, you
get
bot
h in
stru
men
t and
app
lica
tion
sup
port
.
Ab
out
thi
s M
anu
al
Incl
uded
in
this
man
ual
are
inst
ruct
ions
for
set
ting
up
your
A
quaL
ab L
ITE
, ver
ifyi
ng th
e ca
libr
atio
n of
the
inst
rum
ent,
prep
arin
g sa
mpl
es,
and
mai
ntai
ning
and
car
ing
for
your
in
stru
men
t. P
leas
e re
ad t
hese
ins
truc
tion
s be
fore
ope
rati
ng
your
Aqu
aLab
LIT
E to
ens
ure
that
the
inst
rum
ent p
erfo
rms
to it
s fu
ll p
oten
tial
.
No
te t
o o
ur A
qua
Lab
LIT
E U
sers
Thi
s m
anua
l is
wri
tten
to a
id th
e en
d us
er in
und
erst
andi
ng
the
basi
c co
ncep
ts o
f w
ater
act
ivit
y, e
nabl
ing
them
to
use
our
inst
rum
ent
wit
h co
nfid
ence
. E
very
eff
ort
has
been
m
ade
to e
nsur
e th
at t
he c
onte
nt o
f th
is m
anua
l is
cor
rect
an
d sc
ient
ific
ally
sou
nd.
AquaLab LITE
9. Further Reading
47
Seiler, D
.A.L
. (1979). The m
ould-free shelf life of bakery products. F
MB
RA
Bulletin. A
pril(2):71-74.
Beverages/S
oup
s/Sau
ces/Preserves
Carson, K
.J., J.L. C
ollins, and M.P. P
enfield. (1994). Unre-
fined, dried apple pomace as a potential food ingredi-
ent. Journal of Food S
cience. 59:1213-1215.D
urrani, M.J., R
. Khan, M
. Saeed, and A
. Khan. (1992).
Developm
ent of
concentrated beverages
from
Anna
apples with or w
ithout added preservatives by control -ling activity of w
ater for shelf stability. Sarhad Journal
of Agriculture. 8:23-28.
Ferragut, V
., J.A. S
alazar, and A. C
hiralt. (1993). Stability in the conservation of em
ulsified sauces low in oil con -
tent. Alim
entaria. 30:67-69.K
usumegi,
K.,
T. Takahashi,
and M
. M
iyagi. (1996).
Effects of addition of sodium
citrate on the pasteurizing conditions in “T
uyu”, Japanese noodle soup. Journal of the Japanese S
ociety for Food S
cience and Technology. 43:740-747.
Sa, M
.M. and A
.M. S
ereno. (1993). Effect of tem
perature on sorption isotherm
s and heats of sorption of quince jam
. International Journal of Food S
cience and Tech -nology. 28:241-248
Pharm
aceutica
ls/Co
smetics
Ahlneck, C
. and G. Z
ografi. (1990). The m
olecular basis of m
oisture effects on the physical and chemical stability
of drugs in the solid state. International Journal of Phar-
maceutics. 62:87-95.
Enigl, D
.C. and K
.M. S
orrels. (1997). Water A
ctivity and S
elf-Preserving F
ormulas. In: P
reservative- Free and
Self-P
reserving Cosm
etics and Drugs: P
rinciples and
AquaLab LITE
1. Introduction
2
Custo
mer Sup
po
rtIf you ever need assistance w
ith your AquaL
ab LIT
E, or if
you just have questions or feedback, there are several ways
to contact us. Custom
er service representatives are available to speak w
ith you Monday thru Friday, betw
een 7am and
5pm Pacific tim
e.
NO
TE
: If you purchased your AquaL
ab LIT
E through a
distributor, please contact them for assistance.
E-m
ail: su
pp
ort@aq
ualab
.com or sales@
aqu
alab.com
Ph
one:
1-509-332-5601
Fax:
1-509-332-5158
If contacting us by email or fax, please include as part of
your message your instrum
ent’s serial number, your nam
e, address, phone, and fax num
ber.
Wa
rranty
AquaL
ab LIT
E has a 30-day satisfaction guarantee and a one-
year warranty on parts and labor. To validate your w
arranty, please com
plete and return the warranty card included w
ith this m
anual within 30 days. Y
ou can return your warranty inform
a-tion by fax, e-m
ail, phone or by mailing the postage-paid card.
Please include all the information requested on the card. It is
necessary for Decagon to have your current m
ailing address and telephone num
ber in case we need to send updated product
information to you.
Aqu
aLab
LIT
E9.
Fur
ther
Rea
ding
46
ing
pret
reat
men
t on
col
or a
nd t
extu
re o
f ap
ple
slic
es a
t va
riou
s w
ater
act
ivit
ies.
Foo
d R
esea
rch
Inte
rnat
iona
l. 28
:83-
86.
Kir
anou
dis,
C.T
., Z
.B. M
arou
lis,
E. T
sam
i, an
d K
.D. M
ari-
nos.
(19
93).
Equ
ilib
rium
moi
stur
e co
nten
t an
d he
at o
f de
sorp
tion
of
som
e ve
geta
bles
. Jo
urna
l of
Foo
d E
ngi-
neer
ing.
20:
55-7
4.M
akow
er, B
. and
G.L
. Deh
orit
y. (
1943
). E
quil
ibri
um m
ois-
ture
con
tent
of
dehy
drat
ed v
eget
able
s.In
dust
rial
and
Eng
inee
ring
Che
mis
try.
35(
2):1
93-1
97.
Mal
tini
, E.,
D. T
orre
ggia
ni, B
.R. B
rove
tto,
and
G. B
erto
lo.
(199
3). F
unct
iona
l pro
pert
ies
of r
educ
ed m
oist
ure
frui
ts
as i
ngre
dien
ts i
n fo
od s
yste
ms.
Foo
d R
esea
rch
Inte
rna-
tion
al. 2
6:41
3-41
9.Z
hang
, X.W
., X
. Liu
, D.X
. Gu,
W. Z
hou,
R.L
. Wan
g, a
nd P
. L
iu.
(199
6).
Des
orpt
ion
isot
herm
s of
som
e ve
geta
bles
. Jo
urna
l of
the
Sci
ence
of
Foo
d an
d A
gric
ultu
re. 7
0:30
3-30
6.
Bak
ed G
ood
s an
d C
erea
lsA
ram
ouni
, F.M
., K
.K. K
one,
J.A
. Cra
ig, a
nd D
.-Y
.C. F
ung.
(1
994)
. G
row
th o
f C
lost
ridi
um s
poro
gene
s PA
367
9 in
ho
me-
styl
e ca
nned
qui
ck b
read
s. J
ourn
al o
f F
ood
Pro
-te
ctio
n. 5
7:88
2-88
6.C
law
son,
A.R
. an
d A
.J.
Tayl
or.
(199
3).
Che
mic
al c
hang
es
duri
ng c
ooki
ng o
f w
heat
. Foo
d C
hem
istr
y. 4
7:33
7-34
3.
Góm
ez, R
., F
erna
ndez
-Sal
guer
o J.
, M.A
. Car
mon
a, a
nd D
. S
anch
ez.
(199
3).
Wat
er a
ctiv
ity
in f
oods
wit
h in
term
e-di
ate
moi
stur
e le
vels
: B
aker
y an
d co
nfec
tion
ery
prod
-uc
ts: M
isce
llan
y. A
lim
enta
ria.
30:
55-5
7.M
ichn
iew
icz,
J.,
C.G
. B
ilia
deri
s, a
nd W
. B
ushu
k. (
1992
).
Eff
ect
of a
dded
pen
tosa
ns o
n so
me
prop
erti
es o
f w
heat
br
ead.
Foo
d C
hem
istr
y. 4
3:25
1-25
7.
Aqu
aLab
LIT
E1.
Intr
oduc
tion
3
Selle
r’s
Lia
bil
ity
Selle
r w
arra
nts
new
equ
ipm
ent
of i
ts o
wn
man
ufac
ture
aga
inst
de
fect
ive
wor
kman
ship
and
mat
eria
ls f
or a
per
iod
of o
ne y
ear
from
dat
e of
rec
eipt
of
equi
pmen
t (t
he r
esul
ts o
f or
dina
ry w
ear
and
tear
, ne
glec
t, m
isus
e, a
ccid
ent
and
exce
ssiv
e de
teri
orat
ion
due
to c
orro
sion
fro
m a
ny c
ause
are
not
to
be c
onsi
dere
d a
defe
ct);
but
Sel
ler’
s lia
bilit
y fo
r de
fect
ive
part
s sh
all i
n no
eve
nt
exce
ed t
he f
urni
shin
g of
rep
lace
men
t pa
rts
F.O
.B.
the
fact
ory
whe
re o
rigi
nally
man
ufac
ture
d. M
ater
ial a
nd e
quip
men
t cov
ered
he
reby
whi
ch i
s no
t m
anuf
actu
red
by S
elle
r sh
all
be c
over
ed
only
by
the
war
rant
y of
its
man
ufac
ture
r. Se
ller
shal
l not
be
lia-
ble
to B
uyer
for
los
s, d
amag
e or
inj
urie
s to
per
sons
(in
clud
ing
deat
h),
or t
o pr
oper
ty o
r th
ings
of
wha
tsoe
ver
kind
(in
clud
ing,
bu
t no
t w
ithou
t lim
itatio
n, l
oss
of a
ntic
ipat
ed p
rofi
ts),
occa
-si
oned
by
or a
risi
ng o
ut o
f th
e in
stal
latio
n, o
pera
tion,
use
, mis
-us
e,
nonu
se,
repa
ir,
or
repl
acem
ent
of
said
m
ater
ial
and
equi
pmen
t, or
out
of t
he u
se o
f any
met
hod
or p
roce
ss fo
r whi
ch
the
sam
e m
ay b
e em
ploy
ed. T
he u
se o
f th
is e
quip
men
t co
nsti-
tute
s B
uyer
’s a
ccep
tanc
e of
the
term
s se
t for
th in
this
war
rant
y.
The
re a
re n
o un
ders
tand
ings
, re
pres
enta
tions
, or
war
rant
ies
of
any
kind
, exp
ress
, im
plie
d, s
tatu
tory
or o
ther
wis
e (i
nclu
ding
, but
w
ithou
t lim
itatio
n, th
e im
plie
d w
arra
ntie
s of
mer
chan
tabi
lity
and
fitn
ess
for a
par
ticul
ar p
urpo
se),
not e
xpre
ssly
set
fort
h he
rein
.
AquaLab LITE
9. Further Reading
45
in Metro Toronto. Journal of F
ood Protection. 59:1007-
1010.L
uecke, F.K
. (1994).
Ferm
ented m
eat products.
Food
Research International. 27:299-307.
Minegishi, Y
., Y. Tsukam
asa, K. M
iake, T. Shim
asaki, C.
Imai, M
. Sugiyam
a, and H. S
hinano. (1995). Water
activity and microflora in com
mercial vacuum
-packed sm
oked salmons. Journal of the F
ood Hygienic S
ociety of Japan. 36:442-446.
Shim
asaki, T., K. M
iake, Y. Tsukam
asa, M.A
. Sugiyam
a, Y
. Minegishi, and H
. Shinano. (1994). E
ffect of Water
Activity and Storage Tem
perature on the Quality and
Microflora of S
moked S
almon. N
ippon Suisan G
akkai -shi. 60:569-576.
Dairy P
rodu
ctsF
resno, J.M., M
.E. Tornadijo, J. C
arballo, P.J. Gonzalez,
and A
. B
ernardo. (1996).
Characterization
and bio-
chemical changes during the ripening of a S
panish craft goat's m
ilk cheese (Arm
ada variety). Food C
hemistry.
55:225-230.K
ombila, M
.E. and C
. Lacroix. (1991). T
he effect of com-
binations of salt, lactose and glycerol on the water
activity (aw
) of cheese spreads. Canadian Institute of
Food S
cience and Technology Journal. 24:233-238.P
isecky, J. (1992). Water activity of m
ilk powders. M
ilch-w
issenschaft. 47:3-7.V
ivier, D., R
. Ratom
ahenina, and P. Galzy. (1994). C
harac-teristics of m
icrococci from the surface of R
oquefort cheese. Journal of A
pplied Bacteriology. 76:546-552.
Fru
its and
Vegetab
lesB
everidge, T. and S.E
. Weintraub. (1995). E
ffect of blanch-
AquaLab LITE
2. About the A
quaLab LITE
4
2. A
bo
ut the Aq
uaLa
b LITE
The A
quaLab L
ITE
is designed to be a simple, rapid,
bench-top system for m
easurement of w
ater activity. It is easy to use, durable, and requires little m
aintenance.
Aq
uaLa
b LITE a
nd w
ater a
ctivity
Water activity (a
w) is a m
easurement of the energy status of
the water in a system
. It indicates how tightly w
ater is “bound”, structurally or chem
ically, within a substance.
Water activity is the relative hum
idity of air in equilibrium
with a sam
ple in a sealed measurem
ent chamber. T
he con -cept of w
ater activity is of particular importance in deter-
mining
product quality
and safety.
Water
activity influences color, odor, flavor, texture and shelf-life of m
any products. It predicts safety and stability w
ith respect to m
icrobial growth, chem
ical and biochemical reaction rates,
and physical properties. For a m
ore detailed definition of w
ater activity as it pertains to products, please refer to C
hapter 8: “Theory: W
ater Activity of P
roducts”.
Ho
w A
qua
Lab
LITE wo
rks
AquaL
ab LIT
E uses a dielectric hum
idity sensor to mea-
sure the water activity
of a sample. W
ith this technique, a special hygroscopic polym
er is placed between tw
o porous electrodes in the headspace of a sealed cham
ber. The elec-
trical properties of the polymer change depending on the
relative humidity of the cham
ber. The electrodes give a sig -
nal based upon the relative humidity in the closed cham
ber. T
his signal is then translated by the firmw
are and displayed as w
ater activity on the instrument's display. A
t equilib-
Aqu
aLab
LIT
E9.
Fur
ther
Rea
ding
44
mon
ocyt
ogen
es.
Let
ters
In
A
ppli
ed
Mic
robi
olog
y.
15:1
03-1
05.
Gar
cia
de F
erna
ndo,
G.D
., O
. Dia
z, M
. Fer
nand
ez, a
nd J
.A.
Ord
onez
. (1
992)
. C
hang
es i
n w
ater
act
ivit
y of
sel
ecte
d so
lid
cult
ure
med
ia th
roug
hout
incu
bati
on. F
ood
Mic
ro-
biol
ogy.
9:7
7-82
.K
untz
, L
.A.
(199
2).
Kee
ping
mic
roor
gani
sms
in c
ontr
ol.
Foo
d P
rodu
ct D
esig
n. A
ugus
t:44
-51.
Mil
ler,
A.J
. (1
992)
. C
ombi
ned
wat
er a
ctiv
ity
and
solu
te
effe
cts
on g
row
th a
nd s
urvi
val
of L
iste
ria
mon
ocyt
oge-
nes.
Sco
tt A
. Jou
rnal
of
Foo
d P
rote
ctio
n. 5
5:41
4-41
8.To
kuok
a, K
. and
T. I
shit
ani.
(199
1). M
inim
um w
ater
act
iv-
itie
s fo
r th
e gr
owth
of
yeas
ts i
sola
ted
from
hig
h-su
gar
food
s. J
ourn
al o
f G
ener
al a
nd A
ppli
ed M
icro
biol
ogy.
37
:111
-119
.
Wa
ter
Act
ivit
y i
n Fo
od
sM
eat
and
Sea
food
Che
n, N
. an
d L
.A.
She
lef.
(19
92).
Rel
atio
nshi
p be
twee
n w
ater
act
ivit
y, s
alts
of
lact
ic a
cid,
and
gro
wth
of
Lis
teri
a m
onoc
ytog
enes
in
a m
eat
mod
el s
yste
m.
Jour
nal
of
Foo
d P
rote
ctio
n. 5
5:57
4-57
8.C
lave
ro,
M.R
.S.
and
L.R
. B
euch
at.
(199
6).
Sur
viva
l of
E
sche
rich
ia c
oli
O15
7:H
7 in
bro
th a
nd p
roce
ssed
sal
-am
i as
inf
luen
ced
by p
H,
wat
er a
ctiv
ity,
and
tem
pera
-tu
re a
nd s
uita
bili
ty o
f m
edia
for
its
rec
over
y. A
ppli
ed
and
Env
iron
men
tal M
icro
biol
ogy.
62:
2735
-274
0.H
and,
L.
(199
4).
Con
trol
ling
wat
er a
ctiv
ity
and
pH i
n sn
ack
stic
ks. M
eat M
arke
ting
and
Tec
hnol
ogy.
May
:55-
56.
Lee
, M
.B.
and
S.
Styl
iadi
s. (
1996
). A
sur
vey
of p
H a
nd
wat
er a
ctiv
ity
leve
ls i
n pr
oces
sed
sala
mis
and
sau
sage
s
Aqu
aLab
LIT
E2.
Abo
ut th
e A
quaL
ab L
ITE
5
rium
, the
rel
ativ
e hu
mid
ity
of t
he a
ir i
n th
e ch
ambe
r is
the
sa
me
as th
e w
ater
act
ivit
y of
the
sam
ple.
Acc
ura
cyT
he A
quaL
ab L
ITE
is
accu
rate
to
±0.0
15 a
w.
For
man
y ap
plic
atio
ns,
this
acc
urac
y is
mor
e th
an a
dequ
ate.
If
you
requ
ire
high
er a
ccur
acy
in y
our
mea
sure
men
ts,
we
reco
m-
men
d yo
u us
e D
ecag
on's
Aqu
aLab
wat
er a
ctiv
ity
met
er,
whi
ch i
s a
lab-
grad
e, b
ench
-top
ins
trum
ent
that
has
an
accu
racy
of
±0
.003
a w
an
d m
easu
res
base
d up
on
the
chil
led-
mir
ror
dew
poin
t m
etho
d.
Con
tact
D
ecag
on
for
mor
e de
tail
s.
Spec
ific
ati
ons
•R
ange
: 0 to
1.0
00 a
w
•A
ccur
acy:
±0.
015a
w
•R
esol
utio
n: ±
0.00
1aw
•M
easu
rem
ent T
ime:
5 m
inut
es
•S
enso
rs: D
iele
ctri
c hu
mid
ity
sens
or a
nd in
frar
ed s
am-
ple
tem
pera
ture
sen
sor
•C
ase
Dim
ensi
ons:
6 x
7 in
ches
(15
cm x
17.
78cm
), o
val
•W
eigh
t: 1
.5 k
g (3
.3 lb
s.)
•P
ower
: 110
V A
C a
dapt
er
AquaLab LITE
9. Further Reading
43
Foo
d Q
uality
and
Safety
Brandt, L
. (1996). Bound for success. C
ontrolling water
activity gives technologists the edge in developing safe, shelf-stable foods. F
ood Form
ulating. Septem
ber:41-48.
Franks, F. (1982). W
ater activity as a measure of biological
viability and
quality control.
Cereal
Foods
World.
27(9):403-407.H
ardman, T.M
. (1988). Water and F
ood Quality. E
lseiver P
ress, London.
Kress-R
ogers, E. (1993). F
ood quality measurem
ent. Food
Industry New
s. Septem
ber:23-26.M
cMeekin, T.A
. and T. Ross. (1996). S
helf life prediction: Status and future possibilities. International Journal of F
ood Microbiology. 33:65-83.
Rockland, L
.B. and G
.F. Stewart. (1981). W
ater Activity:
Influences on
Food
Quality.
Academ
ic P
ress, N
ew
York.
Seow
, C.C
., T.T. Teng, and C.H
. Quah. (1988). F
ood Pres-
ervation by Moisture C
ontrol. Elsevier, N
ew Y
ork.Taoukis, P., W
. Breene, and T.P. L
abuza. (1988). Intermedi-
ate moisture foods. A
dvances in Cereal S
cience and Technology. 9:91-128.
Wa
ter Activ
ity a
nd M
icrob
iolo
gy
Beuchat, L
.R. (1981). M
icrobial stability as affected by w
ater activity. Cereal F
oods World. 26(7):345-349.
Chen, H
.C. (1995). S
eafood microorganism
s and seafood safety. Journal of F
ood and Drug A
nalysis. 3:133-144.F
arber, J.M., F. C
oates, and E. D
aley. (1992). Minim
um
water activity requirem
ents for the growth of L
isteria
AquaLab LITE
2. About the A
quaLab LITE
6
Out o
f the BoxC
omponents of your A
quaLab L
ITE
system:
Your A
quaLab L
ITE
should have been shipped to you with
the following item
s:
•A
quaLab L
ITE
•O
perator's Manual
•Q
uick Start Guide
•A
C pow
er adapter*
•U
SB
interface cable
•100 disposable S
ample cups
•3 vials each of the follow
ing calibration solutions: 0.920 aw
solution (2.33 molal N
aCl)
0.760 aw solution (6.0 m
olal NaC
l) 0.500 aw
solution (8.57 molal L
iCl)
0.250 aw solution (13.41 m
olal LiC
l)
Note: T
he AquaL
ab LIT
E is shipped w
ith a 110V A
C pow
er connector for use in N
orth Am
erica and Japan. If you live in a country that uses 220V, you w
ill need to acquire a 220V
AC
adapter before using the AquaL
ab LIT
E.
Aqu
aLab
LIT
E9.
Fur
ther
Rea
ding
42
9. F
urth
er R
ead
ing
Wa
ter
Act
ivit
y T
heo
ry a
nd
Mea
sure
men
tB
arbo
sa-C
anov
as,
G.,
A.J
. F
onta
na,
S.J
. S
chm
idt,
and
T.P.
L
abuz
a. 2
007.
Wat
er A
ctiv
ity
in F
oods
: F
unda
men
tals
an
d A
ppli
cati
ons.
Bla
ckw
ell P
ibli
shin
g, A
mes
, IA
.D
uckw
orth
, R
. (1
975)
. W
ater
Rel
atio
ns o
f F
oods
. A
ca-
dem
ic P
ress
, New
Yor
k.G
omez
-Dia
z, R
. (1
992)
. W
ater
act
ivit
y in
foo
ds:
Det
erm
i-na
tion
met
hods
. Ali
men
tari
a. 2
9:77
-82.
Gre
ensp
an, L
. (19
77).
Hum
idit
y fi
xed
poin
ts o
f bi
nary
sat
-ur
ated
aqu
eous
sol
utio
ns.
Jour
nal
of R
esea
rch
of t
he
Nat
iona
l Bur
eau
of S
tand
ards
- A
.Phy
sics
and
Che
mis
-tr
y. 8
1A:8
9-96
.P
rior
, B.A
. (19
79).
Mea
sure
men
t of
wat
er a
ctiv
ity
in f
oods
: A
rev
iew
. Jou
rnal
of
Foo
d P
rote
ctio
n. 4
2(8)
:668
-674
.T
roll
er,
J.A
. an
d J.
H.B
. C
hris
tian
. (1
978)
. W
ater
Act
ivit
y an
d F
ood.
Aca
dem
ic P
ress
, New
Yor
k.T
roll
er, J
.A. a
nd V
.N. S
cott
. (19
92).
Mea
sure
men
t of
wat
er
acti
vity
()
and
acid
ity.
In:
Com
pend
ium
of
Met
hods
for
th
e M
icro
biol
ogic
al E
xam
inat
ion
of F
oods
. V
ande
r-za
nt, C
. and
D.F
. Spl
itts
toes
ser
(eds
.) A
mer
ican
Pub
lic
Hea
lth
Ass
ocia
tion
, Was
hing
ton,
D.C
. pp.
135
-151
.V
an d
en B
erg,
C. (
1985
). W
ater
act
ivit
y. I
n: C
once
ntra
tion
an
d D
ryin
g of
Foo
ds.
Mac
Car
thy,
D.
(ed.
) E
lsev
ier,
Lon
don.
pp.
11-
35.
Aqu
aLab
LIT
E2.
Abo
ut th
e A
quaL
ab L
ITE
7
Fea
ture
s
Fro
nt v
iew
of A
quaL
ab L
ITE
Side
vie
w o
f Aqu
aLab
LIT
E
Op
enin
gL
atch
Lef
t, m
idd
lean
d r
igh
tfu
nct
ion
b
utt
ons
LC
D s
cree
n
AC
pow
erin
put
Dat
a p
ort
(op
tion
al)
AquaLab LITE
8. Theory: Water A
ctivity in Products
41
tries to use water content to infer the stability or safety of a
product. Typically, large safety margins are built in to w
ater content specifications to allow
for these uncertainties.
While the sorption isotherm
is often used to infer water
activity from w
ater content, one could easily go the other direction and use the w
ater activity to infer the water con-
tent. This is particularly attractive because w
ater activity is m
uch more quickly m
easured than water content. T
his m
ethod gives particularly good precision in the center of the isotherm
. In order to infer water content from
water
activity, one needs an isotherm for the particular product;
produced, ideally, using the process that brings the product to its final w
ater content. Decagon now
offers a Isotherm
Service as w
ell as a Isotherm G
enerator using a Dyam
ic D
ewpoint m
ethod.
For exam
ple, if one were using the A
quaLab to m
onitor the w
ater content of dried potato flakes, one would m
easure the w
ater activity and water content of potato flakes dried
to varying degrees using the standard drying process for those flakes. A
n isotherm w
ould be constructed using those data, and the w
ater content would be inferred using the
measured w
ater activity of samples and that isotherm
.
The im
portance of the concept of water activity of foods,
pharmaceuticals, and cosm
etics cannot be over empha -
sized. Water activity is a m
easure of the energy status of the w
ater in a system. M
ore importantly, the usefulness of
water activity in relation to m
icrobial growth, chem
ical reactivity, and stability over w
ater content has been shown.
AquaLab LITE
3. Getting Started
8
3. G
etting Sta
rted
Prepa
ring fo
r Op
eratio
nO
peration of the AquaL
ab LIT
E is very sim
ple. To ensure that your A
quaLab L
ITE
operates correctly and consis-tently, alw
ays place it on a level surface when m
easuring. T
his reduces the chance that sample m
aterial will spill
inside the instrument. To avoid inaccurate readings, place
your AquaL
ab LIT
E in a location w
here the temperature
remains fairly stable. T
his location should be well aw
ay from
air conditioner and heater vents, open window
s, out-side doors, refrigerator exhausts, or other item
s that may
cause rapid
temperature
fluctuation. O
nce you
have ensured that you have a stable w
orking environment, you
are ready to begin sampling.
After finding a good location for your A
quaLab L
ITE
,plug the pow
er cord into the connector on the side of the instrum
ent as pictured below.
Turning the A
qua
Lab
LITE on
After the pow
er adaptor is connected to the AquaL
ab LIT
E
and plugged into an outlet, the instrument autom
atically
Aqu
aLab
LIT
E8.
The
ory:
Wat
er A
ctiv
ity in
Pro
duct
s
40
dilu
tes
the
solu
te,
decr
easi
ng t
he o
smot
ic p
ress
ure,
and
in
crea
sing
the
wat
er a
ctiv
ity.
Sin
ce m
icro
bial
cel
ls a
re h
igh
conc
entr
atio
ns o
f so
lute
sur
roun
ded
by s
emi-
perm
eabl
e m
embr
anes
, th
e os
mot
ic e
ffec
t on
the
fre
e en
ergy
of
the
wat
er i
s im
port
ant
for
dete
rmin
ing
mic
robi
al w
ater
rel
a -ti
ons
and
ther
efor
e th
eir
acti
vity
.
Mat
rix
Eff
ects
The
sam
ple
mat
rix
affe
cts
wat
er a
ctiv
ity
by p
hysi
call
y bi
ndin
g w
ater
wit
hin
its
stru
ctur
e th
roug
h ad
hesi
ve a
nd
cohe
sive
for
ces
that
hol
d w
ater
in p
ores
and
cap
illa
ries
, and
to
par
ticl
e su
rfac
es.
If c
ellu
lose
or
prot
ein
wer
e ad
ded
to
wat
er,
the
ener
gy s
tatu
s of
the
wat
er w
ould
be
redu
ced.
W
ork
wou
ld n
eed
to b
e do
ne t
o ex
trac
t th
e w
ater
fro
m t
his
mat
rix.
Thi
s re
duct
ion
in e
nerg
y st
atus
of
the
wat
er i
s no
t os
mot
ic, b
ecau
se th
e ce
llul
ose
or p
rote
in c
once
ntra
tion
s ar
e fa
r to
o lo
w t
o pr
oduc
e an
y si
gnif
ican
t di
luti
on o
f w
ater
. T
he r
educ
tion
in
ener
gy i
s th
e re
sult
of
dire
ct p
hysi
cal
bind
ing
of w
ater
to
the
cell
ulos
e or
pro
tein
mat
rix
by
hydr
ogen
bon
ding
and
van
der
Waa
l fo
rces
. A
t hi
gher
w
ater
act
ivit
y le
vels
, ca
pill
ary
forc
es a
nd s
urfa
ce t
ensi
on
can
also
pla
y a
role
.
Sorp
tio
n Is
oth
erm
sR
elat
ing
Wat
er A
ctiv
ity
to W
ater
Con
ten
tC
hang
es i
n w
ater
con
tent
aff
ect
both
the
osm
otic
and
mat
-ri
c bi
ndin
g of
wat
er in
a p
rodu
ct. T
hus
a re
lati
onsh
ip e
xist
s be
twee
n th
e w
ater
act
ivit
y an
d w
ater
con
tent
of
a pr
oduc
t. T
his
rela
tion
ship
is
call
ed t
he s
orpt
ion
isot
herm
, an
d is
un
ique
for
eac
h pr
oduc
t. F
igur
e 1
show
s a
typi
cal i
soth
erm
. B
esid
es b
eing
uni
que
to e
ach
prod
uct,
the
isot
herm
cha
nges
de
pend
ing
on w
heth
er it
was
obt
aine
d by
dry
ing
or w
etti
ng
the
sam
ple.
The
se f
acto
rs n
eed
to b
e ke
pt i
n m
ind
if o
ne
Aqu
aLab
LIT
E3.
Get
ting
Star
ted
9
turn
s on
. Pre
ssin
g an
y on
e of
the
thre
e bu
tton
s w
ill t
urn
the
Aqu
aLab
LIT
E o
n if
the
ins
trum
ent
has
been
tur
ned
off
or
has
auto
mat
ical
ly s
hut o
ff if
left
idle
for
mor
e th
an 1
5 m
in-
utes
. The
fol
low
ing
scre
ens
wil
l app
ear
on th
e di
spla
y:
then
:
Thi
s is
the
mai
n di
spla
y m
enu
for
the
Aqu
aLab
LIT
E. T
he
top
line
dis
play
s w
ater
act
ivit
y to
thre
e di
gits
. The
nex
t lin
e di
spla
ys t
he s
ampl
e te
mpe
ratu
re i
n de
gree
s C
elsi
us.
The
re
ctan
gula
r ba
r is
a m
easu
rem
ent
prog
ress
ind
icat
or.
The
ic
ons
on t
he b
otto
m l
ine
corr
espo
nd t
o th
e bu
tton
s lo
cate
d be
low
the
m.
The
ins
trum
ent
wil
l pe
rfor
m a
spe
cifi
c fu
nc-
tion
whe
n a
butt
on n
ext
to a
n ic
on i
s pr
esse
d. T
he l
eft
but-
ton
turn
s th
e A
quaL
ab L
ITE
off
. T
he c
ente
r bu
tton
sta
rts
the
wat
er a
ctiv
ity
mea
sure
men
t. T
he r
ight
but
ton
proc
eeds
to
a n
ew m
enu
scre
en.
AquaLab LITE
8. Theory: Water A
ctivity in Products
39
both phases. It is this fact that allows us to m
easure the w
ater potential of the vapor phase and use that to determine
the water potential of the liquid phase. G
radients in are
driving forces for moisture m
ovement. T
hus, in an isother-m
al system, w
ater tends to move from
regions of high w
ater potential (high water activity) to regions of low
water
potential (low w
ater activity). Water content is not a driv-
ing force for water m
ovement, and therefore can not be
used to predict the direction of water m
ovement, except in
homogeneous m
aterials.
Facto
rs in Determ
ining W
ater
Potentia
lT
he water potential of the w
ater in a system is influenced
by factors that affect the binding of water. T
hey include osm
otic, m
atric, and
pressure effects.
Typically w
ater activity is m
easured at atmospheric pressure, so only the
osmotic and m
atric effects are important.
Osm
otic Effects
Osm
otic effects are well know
n from biology and physical
chemistry. W
ater is diluted when a solute is added. If this
diluted water is separated from
pure water by a sem
i-per-m
eable mem
brane, water tends to m
ove from the pure
water side through the m
embrane to the side w
ith the added solute. If sufficient pressure is applied to the solute-w
ater m
ixture to just stop the flow, this pressure is a m
easure of the osm
otic potential of the solution. Addition of one m
ole of an ideal solute to a kilogram
of water produces an
osmotic pressure of 22.4 atm
. This low
ers the water activ -
ity of the solution from 1.0 to 0.98 aw . F
or a given amount
of solute,
increasing the
water
content of
the system
s
AquaLab LITE
3. Getting Started
10
The Menus
Pressing the right button from
the main display m
enu will
proceed to a system m
enu screen shown below
.
From
this system m
enu, many functions of the A
quaLab
LIT
E m
ay be accessed. Press the left button to scroll
through the options on the screen. Pressing the button an
additional time w
hen the “About” function is highlighted
will scroll back to the “C
alibrate” function. Press the center
button to select the highlighted function. Press the right
button to return to the main display m
enu.
“Calib
rate” Fu
nction
Press the center button w
hen the “Calibrate” function is
highlighted to proceed to the Calibration m
enu. The fol -
lowing screen w
ill appear:
Aqu
aLab
LIT
E8.
The
ory:
Wat
er A
ctiv
ity in
Pro
duct
s
38
In a
ddit
ion
to e
quil
ibri
um b
etw
een
the
liqu
id p
hase
wat
er
in th
e sa
mpl
e an
d th
e va
por
phas
e, th
e in
tern
al e
quil
ibri
um
of t
he s
ampl
e is
im
port
ant.
If a
sys
tem
is
not
at i
nter
nal
equi
libr
ium
, on
e m
ight
mea
sure
a s
tead
y va
por
pres
sure
(o
ver
the
peri
od o
f m
easu
rem
ent)
whi
ch i
s no
t th
e tr
ue
wat
er a
ctiv
ity
of th
e sy
stem
. An
exam
ple
of th
is m
ight
be
a ba
ked
good
or
a m
ulti
-com
pone
nt f
ood.
Ini
tial
ly o
ut o
f th
e ov
en, a
bak
ed g
ood
is n
ot a
t int
erna
l equ
ilib
rium
; the
out
er
surf
ace
is a
t a
low
er w
ater
act
ivit
y th
an t
he c
ente
r of
the
ba
ked
good
. One
mus
t wai
t a p
erio
d of
tim
e in
ord
er f
or th
e w
ater
to m
igra
te a
nd th
e sy
stem
to c
ome
to in
tern
al e
quil
ib-
rium
. It i
s im
port
ant t
o re
mem
ber
the
rest
rict
ion
of th
e de
f-in
itio
n of
wat
er a
ctiv
ity
to e
quil
ibri
um.
Effe
ct o
f Te
mpe
ratu
re o
n W
ater
Act
ivit
yTe
mpe
ratu
re p
lays
a c
riti
cal
role
in
wat
er a
ctiv
ity
dete
rmi-
nati
ons.
The
mos
t cr
itic
al m
easu
rem
ent
is t
he d
iffe
renc
e be
twee
n sa
mpl
e an
d se
nsor
tem
pera
ture
. B
est
accu
racy
is
ther
efor
e ob
tain
ed w
hen
the
sam
ple
tem
pera
ture
is
near
ch
ambe
r te
mpe
ratu
re.
Wa
ter
Pote
ntia
lS
ome
addi
tion
al in
form
atio
n m
ay b
e us
eful
for
und
erst
and-
ing
wha
t w
ater
act
ivit
y is
and
why
it
is s
uch
a us
eful
mea
-su
re o
f m
oist
ure
stat
us in
pro
duct
s. W
ater
act
ivit
y is
clo
sely
re
late
d to
a
ther
mod
ynam
ic
prop
erty
ca
lled
th
e w
ater
po
tent
ial,
or c
hem
ical
pot
enti
al ()
of
wat
er,
whi
ch i
s th
e ch
ange
in
Gib
bs f
ree
ener
gy (
G)
whe
n w
ater
con
cent
rati
on
chan
ges.
Equ
ilib
rium
occ
urs
in a
sys
tem
whe
n
is t
he
sam
e ev
eryw
here
in
the
syst
em.
Equ
ilib
rium
bet
wee
n th
e li
quid
and
the
vap
or p
hase
s im
plie
s th
at
is
the
sam
e in
Aqu
aLab
LIT
E3.
Get
ting
Star
ted
11
Au
toU
sing
the
“A
uto”
cal
ibra
tion
func
tion
all
ows
the
inst
ru-
men
t to
det
ect
the
inse
rted
cal
ibra
tion
sol
utio
n an
d ad
just
th
e in
stru
men
t wit
hout
fur
ther
inpu
t fro
m th
e us
er.
Man
ual
Usi
ng t
he “
Man
ual”
cal
ibra
tion
fun
ctio
n al
low
s yo
u to
se
lect
a s
tand
ard
for
cali
brat
ion
as s
een
in th
e sc
reen
bel
ow.
NO
TE
: Se
lect
ing
one
stan
dard
typ
e an
d in
sert
ing
anot
her
wil
l in
corr
ectl
y al
ter
the
firm
war
e on
the
ins
trum
ent
and
may
be
hard
to
corr
ect.
Ple
ase
mak
e su
re a
nd i
nser
t th
e co
rrec
t sta
ndar
d w
hen
usin
g “
Man
ual”
mod
e.
Use
the
left
but
ton
to s
crol
l and
sel
ect t
he s
tand
ard
that
you
ar
e us
ing
for
cali
brat
ion,
the
n pr
ess
the
cent
er b
utto
n to
be
gin
the
cali
brat
ion
proc
edur
e (r
efer
to
the
Cal
ibra
tion
se
ctio
n in
the
nex
t ch
apte
r).
To s
top
the
cali
brat
ion
proc
e-du
re a
nd r
etur
n to
the
last
win
dow
, pre
ss th
e ri
ght b
utto
n.
Def
ault
sU
se t
he “
Def
ault
s” o
ptio
n to
res
et t
he i
nstr
umen
ts c
alib
ra-
tion
to th
e fa
ctor
y se
ttin
g.
AquaLab LITE
8. Theory: Water A
ctivity in Products
37
ability and temperature, can affect the relationships, w
ater activity is the best single m
easure of how w
ater affects these processes.
Fig. 1: W
ater Activity D
iagram—
adapted from L
abuza
Water activity of a system
is measured by equilibrating the
liquid phase water in the sam
ple with the vapor phase w
ater in the headspace and m
easuring the relative humidity of the
headspace. In the AquaL
ab LIT
E, a sam
ple is placed in a sam
ple cup which is sealed inside a cham
ber. Inside the cham
ber is a dielectric humidity sensor. C
hanges in the electrical conductance of the dielectric sensor occur as the relative hum
idity of the chamber changes. B
y monitoring
the change in electrical conductance, the relative humidity
of the headspace is computed. W
hen the water activity of
the sample and the relative hum
idity of the air are in equi -librium
, the measurem
ent of the headspace humidity gives
the water activity of the sam
ple.
AquaLab LITE
3. Getting Started
12
“Lan
guage” F
un
ctionT
he AquaL
ab LIT
E com
es to you with E
nglish as the default on-screen user language. If you prefer not to use E
nglish, you can change it to one of a variety of other languages: G
erman, French, Spanish, Italian, Sw
edish, Danish, N
orwe-
gian, Czech, Portuguese, Japanese, Polish, Finnish or C
hi-nese. T
his is done simply by pressing the center button w
hen the “L
anguage” function is highlighted to display the fol-low
ing menu.
Press the left button to scroll to the next language option.
Once the desired language is highlighted, press the center
button to accept it, or press the right button to cancel out of the m
enu.
“Con
trast” Fu
nction
From
the configuration menu, press the left button to scroll
down to C
ontrast. Press the m
iddle button to enter the con-trast adjustm
ent screen. You can then use the up and dow
n arrow
s to adjust the contrast level. Press the m
iddle button to save the contrast.
Aqu
aLab
LIT
E8.
The
ory:
Wat
er A
ctiv
ity in
Pro
duct
s
36
8. T
heo
ry: W
ate
r A
ctiv
ity
in
Pro
duc
ts
Wat
er is
a m
ajor
com
pone
nt o
f fo
ods,
pha
rmac
euti
cals
, and
co
smet
ics.
Wat
er i
nflu
ence
s th
e te
xtur
e, a
ppea
ranc
e, t
aste
an
d sp
oila
ge o
f th
ese
prod
ucts
. The
re a
re tw
o ba
sic
type
s of
w
ater
ana
lysi
s: w
ater
con
tent
and
wat
er a
ctiv
ity.
Wa
ter
Co
nten
tT
he m
eani
ng o
f th
e te
rm w
ater
con
tent
is
fam
ilia
r to
mos
t pe
ople
. It
im
plie
s a
quan
tita
tive
ana
lysi
s to
det
erm
ine
the
tota
l am
ount
of
wat
er p
rese
nt i
n a
sam
ple.
The
pri
mar
y m
etho
d fo
r de
term
inin
g w
ater
con
tent
is
by l
oss
on d
ryin
g or
Kar
l F
ishe
r tit
rati
on,
but
seco
ndar
y m
etho
ds s
uch
as
infr
ared
or
NM
R a
re a
lso
used
. M
oist
ure
cont
ent
dete
rmi-
nati
on i
s es
sent
ial
in m
eeti
ng p
rodu
ct n
utri
tion
al l
abel
ing
regu
lati
ons,
spe
cify
ing
reci
pes
and
mon
itor
ing
proc
esse
s.
How
ever
, wat
er c
onte
nt a
lone
is n
ot a
rel
iabl
e in
dica
tor
for
pred
icti
ng m
icro
bial
res
pons
es a
nd c
hem
ical
rea
ctio
ns i
n m
ater
ials
. T
he l
imit
atio
ns o
f w
ater
con
tent
mea
sure
men
t ar
e at
trib
uted
to
diff
eren
ces
in t
he i
nten
sity
wit
h w
hich
w
ater
ass
ocia
tes
wit
h ot
her
com
pone
nts.
Wa
ter
Act
ivit
yW
ater
act
ivit
y is
a m
easu
re o
f th
e en
ergy
sta
tus
of th
e w
ater
in
a s
yste
m, a
nd t
hus
is a
far
bet
ter
indi
cato
r of
per
isha
bil-
ity
than
wat
er c
onte
nt.
Fig
ure
1 sh
ows
how
the
rel
ativ
e ac
tivi
ty o
f m
icro
orga
nism
s, l
ipid
s an
d en
zym
es r
elat
e to
w
ater
act
ivit
y. W
hile
oth
er f
acto
rs,
such
as
nutr
ient
ava
il-
Aqu
aLab
LIT
E3.
Get
ting
Star
ted
13
“Dia
gnos
tics
” F
un
ctio
nT
he d
iagn
osti
cs s
cree
n al
low
s yo
u to
mon
itor
rea
l tim
e se
n-so
r re
adin
gs o
f th
e A
quaL
ab L
ITE
. It
can
be
used
for
trou
-bl
esho
otin
g if
the
ins
trum
ent
isn’
t re
adin
g pr
oper
ly.
It c
an
also
be
used
to
dete
rmin
e w
hen
your
sam
ple
is t
herm
ally
eq
uili
brat
ed.
“Ab
out”
Fu
nct
ion
Fro
m t
he m
ain
men
u, p
ress
the
mid
dle
butt
on w
hen
the
“Abo
ut”
opti
on i
s hi
ghli
ghte
d to
pro
ceed
to
an i
nstr
umen
t in
form
atio
n sc
reen
. T
he s
cree
n di
spla
ys i
mpo
rtan
t in
for-
mat
ion
abou
t yo
ur A
quaL
ab L
ITE
wat
er a
ctiv
ity
met
er,
incl
udin
g th
e se
rial
num
ber
and
vers
ion
of t
he f
irm
war
e or
op
erat
ion
code
.
AquaLab LITE
7.Repair Instructions
35
you. An extra fee w
ill be charged for rush work. D
ecagon w
ill provide an estimated repair cost, if requested.
Loa
ner Service
Decagon has loaner instrum
ents to keep you measuring
water activity w
hile your instrument is being serviced. If
your AquaL
ab LIT
E is still under calibration w
arranty or you have a service plan w
ith your instrument, there is no
charge for the loaner service.
AquaLab LITE
4. AquaLab LITE O
peration
14
4. A
qua
Lab
LITE Op
eratio
n
Sam
ple Prep
ara
tion a
nd Insertio
nY
our AquaL
ab LIT
E com
es with 100 disposable plastic
sample cups. T
he sample cups are intended to be single-use
disposable cups. We do not recom
mend that you w
ash and re-use your cups. T
here is a chance that a washed cup m
ay still have residual contam
ination from the previous sam
ple or m
ay not be completely dry from
washing. M
ore cups are alw
ays available from D
ecagon when you run out.
Sam
ple Prep
ara
tion
Special care should be taken in preparing the sam
ple in order to get the best readings possible. F
ollow these guide -
lines when preparing sam
ples.
•M
ake sure that the sample to be m
easured is homoge-
neous. Multi-com
ponent samples (e.g., m
uffins with
raisins) or samples that have outside coatings (like
deep-fried, breaded foods) can be measured, but m
ay take
longer to
equilibrate. S
amples
like these
may
require additional preparation (crushing or slicing) to obtain a representative sam
ple.
•C
ompletely cover the bottom
of the cup with the sam
-ple, if possible. A
quaLab L
ITE
is able to accurately m
easure a sample even w
ith small spaces of the cup
bottom exposed. F
or example, raisins only need to be
Aqu
aLab
LIT
E7
.Rep
air I
nstr
uctio
ns
34
2.P
lace
the
Aqu
aLab
LIT
E in
a p
last
ic b
ag to
avo
id d
is-
figu
ring
mar
ks f
rom
the
pack
agin
g.
3.D
on’t
shi
p th
e po
wer
cor
d or
ser
ial c
able
.
4.If
the
orig
inal
pac
kagi
ng is
not
ava
ilab
le, p
ack
the
box
mod
erat
ely
tigh
t wit
h pa
ckin
g m
ater
ial (
e.g.
sty
rofo
ampe
anut
s or
bub
ble
wra
p), e
nsur
ing
the
inst
rum
ent i
ssu
spen
ded
in th
e pa
ckin
g m
ater
ial.
5.O
n th
e R
MA
for
m, p
leas
e ve
rify
the
ship
to a
nd b
ill t
oin
form
atio
n, c
onta
ct n
ame,
and
pro
blem
des
crip
tion
. If
anyt
hing
is in
corr
ect p
leas
e co
ntac
t a D
ecag
on r
epre
-se
ntat
ive.
6.Ta
pe th
e bo
x in
bot
h di
rect
ions
for
add
ed s
uppo
rt.
7.In
clud
e th
e R
MA
num
ber
in th
e at
tent
ion
line
on
the
ship
ping
labe
l.
Sh
ip t
o:D
ecag
on D
evic
es I
nc.
AT
TN
: R
MA
(in
sert
you
r R
MA
#)
2365
NE
Hop
kins
Cou
rtP
ullm
an, W
A 9
9163
Rep
air
Co
sts
Man
ufac
ture
r’s
defe
cts
and
inst
rum
ents
wit
hin
the
one-
year
war
rant
y w
ill b
e re
pair
ed a
t no
char
ge.
Non
-war
rant
y re
pair
cha
rges
for
par
ts, l
abor
and
shi
ppin
g w
ill b
e bi
lled
to
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
15
plac
ed in
the
cup
and
not f
latte
ned
to c
over
the
bott
om.
A l
arge
r sa
mpl
e su
rfac
e ar
ea i
ncre
ases
ins
trum
ent
effi
-ci
ency
by
shor
teni
ng t
he t
ime
need
ed t
o re
ach
vapo
r eq
uili
briu
m.
•F
ill t
he c
up n
o m
ore
than
hal
f-fu
ll o
f sa
mpl
e. A
quaL
abL
ITE
doe
s no
t re
quir
e a
larg
e sa
mpl
e si
ze t
o m
ake
its
read
ing
(wat
er a
ctiv
ity
is n
ot a
vol
umet
ric
mea
sure
-m
ent)
. A
s lo
ng a
s th
e bo
ttom
of
the
cup
is c
over
ed b
yth
e sa
mpl
e, a
nd t
he s
ampl
e is
rep
rese
ntat
ive
of t
hepr
oduc
t to
be
mea
sure
d, a
ccur
ate
read
ings
sho
uld
bepo
ssib
le. I
f th
e sa
mpl
e cu
p is
too
full
, you
ris
k co
ntam
i-na
ting
the
sen
sor,
whi
ch w
ill
lead
to
inac
cura
te r
ead-
ings
.
•M
ake
sure
tha
t th
e ri
m a
nd o
utsi
de o
f th
e sa
mpl
e cu
par
e cl
ean.
Wip
e an
y ex
cess
sam
ple
mat
eria
l fr
om t
heri
m o
f th
e cu
p w
ith
a cl
ean
tiss
ue.
Mat
eria
l le
ft o
n th
eri
m o
r th
e ou
tsid
e of
the
cup
may
con
tam
inat
e th
e sa
m-
ple
cham
ber
and
affe
ct th
e ac
cura
cy o
f re
adin
gs.
If a
sam
ple
wil
l be
read
at s
ome
othe
r ti
me,
put
a li
d on
the
cup
to r
estr
ict
wat
er t
rans
fer.
To s
eal
the
lid,
pla
ce t
ape
or
Par
afil
m®
com
plet
ely
arou
nd t
he c
up/l
id j
unct
ion.
It
is
nece
ssar
y to
sea
l the
cup
if it
wil
l be
a lo
ng ti
me
befo
re th
e m
easu
rem
ent i
s m
ade.
AquaLab LITE
7.Repair Instructions
33
7.R
epa
ir Instructions
NO
TE
: If you purchased your AquaL
ab LIT
E from
one of our international distributors, please contact them
. They
will be able to provide you w
ith local support and service.
When
encountering problem
s w
ith your
AquaL
ab L
ITE
(that can’t be resolved with the help of this m
anual), please
contact D
ecagon C
ustomer
Support
at sup-
, (509) 332-5601 or fax us at (509) 332-5158. P
lease have the serial number and m
odel of the instrum
ent ready .
All A
quaLab L
ITE
’s returning to Decagon for servicing
must be accom
panied with a R
eturn Material A
uthorization (R
MA
) form. P
rior to shipping the instrument, please con-
tact a Decagon custom
er support representative to obtain an R
MA
.
Shipp
ing D
irections:
The follow
ing steps will help to ensure the safe shipping
and processing of your AquaL
ab LIT
E.
1.S
hip your AquaL
ab LIT
E in its original cardboard box
with suspension packaging. If this is not possible, use a
box that has at least 4 inches of space between your
instrument and each w
all of the box.
AquaLab LITE
4.AquaLab LITE O
peration
16
Sam
ple Insertio
n
1.O
pen the AquaL
ab LIT
E by sliding the latch on the
front of the instrument to the right as show
n:
Location of opening latch
The top half of the A
quaLab L
ITE
will autom
atically open to a sam
ple loading position as shown:
AquaL
ab LIT
E in open (loading) position
Aqu
aLab
LIT
E6.
Cle
anin
g an
d M
aint
enan
ce
32
4.R
emov
e th
e fi
lter
. The
sen
sor
bene
ath
does
not
req
uire
cl
eani
ng,
as t
he f
ilte
r do
es a
n ex
cell
ent
job
of p
reve
nt-
ing
dirt
and
con
tam
inat
ion
from
con
tact
ing
the
sens
or.
NO
TE
: T
he
sens
or
is
extr
emel
y se
nsit
ive!
D
o n
ot
tou
ch!
5.T
he s
enso
r fi
lter
can
be
rins
ed w
ith
dist
ille
d w
ater
to
rem
ove
any
cont
amin
atio
n.
If
the
filt
er
cann
ot
be
clea
ned,
the
n re
plac
e it
wit
h a
new
sen
sor
filt
er.
You
r A
quaL
ab L
ITE
com
es w
ith
3 re
plac
eabl
e se
nsor
fil
ters
. If
you
nee
d m
ore,
ple
ase
cont
act D
ecag
on o
r yo
ur lo
cal
dist
ribu
tor.
Rep
lace
the
fil
ter
usin
g tw
eeze
rs,
mak
ing
sure
it is
sec
urel
y pr
esse
d in
pla
ce.
6.U
se a
lin
t fr
ee t
issu
e su
ch a
s a
Kim
wip
e® m
oist
ened
w
ith
dist
ille
d w
ater
or
Isop
ropy
l A
lcoh
ol t
o cl
ean
the
surr
ound
ing
cham
ber
area
an
d in
frar
ed
tem
pera
ture
se
nsor
. Nev
er c
lean
the
filte
r w
ith
Isop
ropy
l Alc
ohol
.
7.T
urn
the
Aqu
aLab
LIT
E u
prig
ht o
nto
the
feet
for
nor
-m
al o
pera
tion
s.
8.V
erif
y th
e ca
libr
atio
n ac
cord
ing
to t
he i
nstr
ucti
ons
out-
line
d in
the
cali
brat
ion
sect
ion
to c
orre
ct a
ny li
near
off
-se
t tha
t may
hav
e oc
curr
ed d
urin
g cl
eani
ng.
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
17
2.P
lace
a p
repa
red
sam
ple
cup
insi
de th
e in
stru
men
t’s
cup
hold
er a
s sh
own,
mak
ing
sure
the
cup
is e
ntir
ely
wit
hin
the
cham
ber
and
the
cup
lid
has
been
rem
oved
.
Sam
ple
cup
load
ed in
cup
hol
der
3.O
nce
the
sam
ple
cup
is p
rope
rly
inse
rted
, lo
wer
the
A
quaL
ab L
ITE
cov
er a
nd p
ress
fir
mly
to la
tch
and
seal
th
e sa
mpl
e ch
ambe
r. Y
ou a
re n
ow r
eady
to
take
rea
d-in
gs (
see
the
“Tak
ing
Mea
sure
men
ts”
sect
ion
belo
w).
NO
TE
: Yo
u m
ay n
eed
to p
ress
dow
n fi
rmly
on
the
fron
t top
of
the
cas
e to
ens
ure
that
the
lat
ch h
as f
ully
eng
aged
and
th
at th
e O
-rin
g is
com
plet
ely
seal
ing
the
cham
ber.
4.W
hen
you
are
fini
shed
wit
h th
e w
ater
act
ivit
y m
easu
re-
men
t on
thi
s sa
mpl
e, s
lide
the
lat
ch t
o th
e ri
ght
to r
e-op
en t
he A
quaL
ab L
ITE
and
rem
ove
the
sam
ple
cup.
To
tak
e an
othe
r w
ater
act
ivit
y m
easu
rem
ent,
inse
rt a
ne
w s
ampl
e as
des
crib
ed a
bove
. W
hen
fini
shed
usi
ng
the
Aqu
aLab
LIT
E, c
lose
the
inst
rum
ent t
o pr
even
t dir
t
AquaLab LITE
6.Cleaning and M
aintenance
31
Ma
intenance
Sen
sor Filter C
leanin
g/Rep
lacemen
tY
ou may periodically need to clean or replace the w
hite Teflon sensor filter if it becom
es dirty. To remove the sen-
sor filter, follow these steps:
1.O
pen the AquaL
ab LIT
E and turn the entire instrum
entupside dow
n.
AquaL
ab LIT
E, open and upside-dow
n
2.L
ocate the white sensor filter inside the s ensor cham
-ber. T
he sensor filter is press-fit into the ring below the
dielectric humidity sensor.
3.To rem
ove the filter, use a pair of fine-tipped tweezers
or a sharp knife-point to gently pry the edge of the fil-
ter.
Water
Activity
Sensor
Filter
AquaLab LITE
4. AquaLab LITE O
peration
18
or contamination from
entering the chamber.
Sam
plin
g Cau
tions
•N
ever leave a samp
le in you
r Aq
uaL
ab L
ITE
after a read
ing h
as been
taken
. Th
e samp
le may sp
ill and
con
tamin
ate the sam
ple ch
amb
er.
•N
ever try to move you
r instru
men
t after a samp
le h
as been
loaded
. Movem
ent m
ay cause th
e samp
le m
aterial to spill an
d con
tamin
ate the sam
ple ch
am-
ber.
•D
o not fill th
e samp
le cup
more th
an h
alf full. O
ver-filled
cup
s will con
tamin
ate the ch
amb
er.
•If a sam
ple h
as a temp
erature th
at is four d
egrees or m
ore high
er than
the A
qu
aLab
LIT
E's ch
amb
er, th
e instru
men
t will d
isplay:
If this screen appears, quickly remove and place a lid on
the sample cup, and allow
the sample to cool before taking
another reading. Warm
samples can cause condensation in
the chamber, especially if they have a high w
ater activity.
Aqu
aLab
LIT
E6.
Cle
anin
g an
d M
aint
enan
ce
30
6.C
lea
ning
and
Ma
inte
nanc
e
Clea
ning
The
Aqu
aLab
LIT
E w
ater
act
ivit
y m
easu
rem
ent
syst
em i
s de
sign
ed to
be
an e
asy-
to-u
se, l
ow m
aint
enan
ce in
stru
men
t. H
owev
er,
it i
s st
ill
impo
rtan
t to
kee
p it
cle
an t
o en
sure
it
wor
ks a
nd f
unct
ions
pro
perl
y. H
ere
are
som
e ti
ps f
or k
eep-
ing
your
Aqu
aLab
LIT
E c
lean
:
•U
se o
nly
a s
oft
cott
on c
loth
to
clea
n t
he
LC
D.
Tis
-su
es c
an s
crat
ch t
he
pla
stic
, cau
sin
g d
amag
e.
•U
se a
moi
st c
otto
n c
loth
or
lin
t-fr
ee t
issu
e to
cle
an
the
rest
of
the
oute
r ca
se.
•B
egin
eac
h st
ep u
sing
a n
ew K
imw
ipe
stri
p w
rapp
ed a
roun
d a
plas
tic s
wab
to
clea
n ch
ambe
r an
d se
nsor
. For
cle
anin
g in
sid
e th
e sa
mp
le
cham
ber
an
d o
ther
inn
er a
reas
, u
se e
ith
er a
lin
t-fr
ee t
issu
e or
cot
ton
sw
ab m
oist
ened
wit
h w
ater
to
clea
n s
amp
le r
esid
ue.
If
you
hav
e sp
ille
d s
amp
le
mat
eria
l on
th
e se
nso
r fi
lter
an
d it
doe
sn't
com
e of
f,
clea
n o
r re
pla
ce t
he
filt
er a
s ex
pla
ined
in
th
e n
ext
sect
ion
. It
is i
mp
orta
nt
that
con
tam
inat
ion
to
this
fi
lter
be
min
imiz
ed, a
s th
e re
l-at
ive
hu
mid
ity
of t
he
sam
ple
is m
easu
red
via
th
e fi
l-te
r.
•T
he
infr
ared
te
mp
erat
ure
se
nso
r n
eed
s to
b
e cl
ean
ed w
ith
a K
imw
ipe
tiss
ue
moi
sten
ed w
ith
dis
-ti
lled
wat
er o
r is
opro
pyl
alc
ohol
. T
his
sen
sor
mu
st
be
free
of
all d
irt
and
lin
t.
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
19
Tak
ing
Mea
sure
men
ts
1.M
ake
sure
the
sam
ple
cup
is in
sert
ed a
s de
scri
bed
in th
e pr
evio
us s
ecti
on.
2.P
ress
the
mid
dle
butt
on f
rom
the
mai
n di
spla
y m
enu
to
star
t the
mea
sure
men
t. T
he w
ater
act
ivit
y an
d te
mpe
ra-
ture
wil
l re
set
to z
ero.
On
the
left
sid
e of
the
dis
play
, a
ther
mom
eter
ico
n ap
pear
s an
d in
dica
tes
if t
he s
ampl
e te
mpe
ratu
re i
s to
o ho
t (4
°C o
r m
ore
abov
e ch
ambe
r te
mpe
ratu
re).
If
the
ther
mom
eter
is
com
plet
ely
fill
ed
then
the
“Sam
ple
too
hot”
err
or m
essa
ge w
ill a
ppea
r on
th
e sc
reen
as
desc
ribe
d ab
ove.
3.O
nce
the
mea
sure
men
t pro
cess
is s
tart
ed, w
ater
act
ivit
y m
easu
rem
ents
and
tem
pera
ture
are
dis
play
ed e
very
10
seco
nds.
Dur
ing
this
tim
e, t
he m
easu
rem
ent
stat
us w
ill
be
indi
cate
d by
th
e pr
ogre
ss
bar
fill
ing
acro
ss
the
scre
en a
nd th
e lo
wer
left
“re
ad”
icon
spi
nnin
g in
pla
ce:
NO
TE:
the
wat
er a
ctiv
ity v
alue
s di
spla
yed
duri
ng th
e m
easu
re-
men
t pro
cess
are
not
the
final
wat
er a
ctiv
ity v
alue
for
this
sam
-pl
e. T
he f
inal
wat
er a
ctiv
ity v
alue
for
the
sam
ple
is t
he v
alue
sh
own
afte
r th
e in
stru
men
t ha
s “b
eepe
d,”
the
prog
ress
bar
is
com
plet
ely
fille
d (s
ee b
elow
), an
d th
e “f
inis
hed”
fla
gs a
re
show
n.
AquaLab LITE
5.Com
puter Interface
29
its own term
inal program (D
ecaTerm) w
hich can be down-
loaded from
http://aqualab.com
/software/D
ecaTerm.zip.
Two other options are TeraTerm
, which is a free program
that can be found on the internet and H
yperterminal w
hich cam
e standard with W
indows prior to W
indows 7.
To use any of these terminal program
s with your A
quaLab
LIT
E, follow
the instructions for the program w
ith the fol-low
ing settings. Be sure to pow
er on the AquaL
ab LIT
E
prior to connecting the US
B interface cable to your com
-puter.
•C
hoose correct Com
port
•S
et/Verify C
om P
roperties
Bits per second 9600
8 D
atabits
No parity
1 stop bit
Flow
control set to none
After successfully connecting the L
ITE
to your computer
and upon completion of a w
ater activity reading the data w
ill be displayed in the terminal program
in the format:
measurem
ent tim
e (m
inutes), sam
ple tem
perature, and
water activity. H
ere is an example:
3.1, 24.3, 0.862
time since
chamber w
as closed
temp
(°C)
aw
AquaLab LITE
4. AquaLab LITE O
peration
20
4.A
fter 5 minutes, the instrum
ent will display the final
water activity and beep 5 tim
es. A checkered flag w
ill flash w
hen the water activity reading is finished.
5.A
t this point, you can either restart the measurem
ent by pressing the m
iddle button again, or you can record the show
n value and take the sample cup out. T
he AquaL
ab L
ITE
does not store any data internally. Make sure to
write dow
n the result or send the data to a computer via
AquaL
ink 4 or a terminal program
(see Chapter 5).
6.W
hen water activity m
easurement of a sam
ple is com-
pleted, push the latch slide to the right to re-open the A
quaLab L
ITE
and remove the sam
ple cup. To take another w
ater activity measurem
ent, insert a new sam
-ple
as described
above. W
hen finished
using the
AquaL
ab LIT
E, close the instrum
ent to prevent dirt or contam
ination from entering the cham
ber. N
OT
E: Sam
ples should be removed after sam
pling. You risk
contaminating
the cham
ber or
damaging
sensors through extended contact w
ith the sample or by spilling liq -
uid samples inside the cham
ber.
Turning the A
qua
Lab
LITE off
To turn off the AquaL
ab LIT
E, either press the left button
or leave it idle for more than 15 m
inutes and it will shut off
Aqu
aLab
LIT
E5.
Com
pute
r Int
erfa
ce
28
5. C
om
put
er I
nter
face
You
r A
quaL
ab L
ITE
com
es w
ith
a U
SB
int
erfa
ce c
able
. U
sing
thi
s ca
ble,
you
can
con
nect
to
your
LIT
E a
nd s
end
wat
er a
ctiv
ity
data
to
a co
mpu
ter
for
furt
her
anal
ysis
and
st
orag
e. T
he i
nter
face
is
run
thro
ugh
the
Aqu
aLin
k 4
Sof
t -w
are
or a
term
inal
com
mun
icat
ion
prog
ram
.
Aq
uaLi
nk 4
So
ftw
are
An
opti
onal
sof
twar
e pr
ogra
m, A
quaL
ink
4, is
ava
ilab
le f
or
use
wit
h yo
ur A
quaL
ab.
Aqu
aLin
k 4
is a
Win
dow
s ba
sed
prog
ram
des
igne
d fo
r da
ta c
olle
ctio
n an
d cu
stom
ized
rep
ort
gene
rati
on f
or a
ll A
quaL
ab m
odel
s.
Aqu
aLin
k 4
logs
w
ater
act
ivit
y, t
empe
ratu
re, t
ime
of m
easu
rem
ent,
and
date
st
amps
alo
ng w
ith
othe
r in
form
atio
n. A
quaL
ink
4 al
so h
as
sam
ple
iden
tifi
cati
on a
nd c
omm
ent
fiel
ds t
hat
you
can
use
to h
elp
anno
tate
the
data
you
r A
quaL
ab is
gat
heri
ng.
A 3
0 da
y tr
ial
CD
of
this
pro
gram
is
atta
ched
to
the
fron
t co
ver
of t
his
man
ual.
If
you
are
inte
rest
ed i
n pu
rcha
sing
a
lice
nce
of A
quaL
ink
4, c
onta
ct D
ecag
on o
r yo
ur l
ocal
dis
-tr
ibut
or.
Usi
ng a
Co
mm
unic
ati
on
Pro
gra
m
NO
TE
: If
usin
g th
e U
SB
inte
rfac
e ca
ble
wit
hou
t A
quaL
ink
4, y
ou w
ill
need
to
inst
all
the
driv
er f
or t
he U
SB
int
erfa
ce
cabl
e.
T
he
driv
er
can
be
dow
nloa
ded
at
http
://
ww
w.a
qual
ab.c
om/s
uppo
rt/u
sb-c
able
-ada
ptor
-dri
ver/
The
re a
re s
ever
al t
erm
inal
pro
gram
opt
ions
. D
ecag
on h
as
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
21
auto
mat
ical
ly. I
f th
e A
quaL
ab L
ITE
has
aut
omat
ical
ly s
hut
itse
lf o
ff,
pres
s an
y bu
tton
to
wak
e up
the
ins
trum
ent
and
disp
lay
the
last
wat
er a
ctiv
ity
mea
sure
men
t.
Ca
lib
rati
on
As
men
tion
ed e
arli
er, t
he A
quaL
ab L
ITE
take
s w
ater
act
iv-
ity
mea
sure
men
ts b
y m
easu
ring
the
cha
nge
in e
lect
rica
l pr
oper
ties
of
a sp
ecia
l po
lym
er h
eld
betw
een
two
elec
-tr
odes
. Due
to
the
natu
re o
f th
e di
elec
tric
hum
idit
y se
nsor
, th
ere
may
be
tim
es w
hen
you
need
to
cali
brat
e. T
his
sec-
tion
exp
lain
s ho
w to
do
so.
Cal
ibra
tion
nee
ds
to b
e ve
rifi
ed d
aily
or
bef
ore
each
use
(i
f n
ot u
sed
dai
ly)
wit
h s
alt
stan
dar
ds.
Cal
ibra
tion
Sta
nd
ard
sT
he A
quaL
ab L
ITE
may
onl
y be
cal
ibra
ted
usin
g on
e of
th
e fo
llow
ing
cali
brat
ion
stan
dard
s li
sted
:
You
rec
eive
d a
smal
l su
pply
of
salt
sta
ndar
ds w
ith
your
in
stru
men
t. T
hese
st
anda
rds
are
spec
iall
y pr
epar
ed
salt
Verif
icat
ion
Stan
dard
Wat
er A
ctiv
ity@
25°C
2.33
m N
aCl
0.92
0 ±
0.01
5
6.0m
NaC
l0.
760
± 0.
015
8.57
m L
iCl
0.50
0 ±
0.01
5
13.4
1m L
iCl
0.25
0 ±
0.01
5
AquaLab LITE
4. AquaLab LITE O
peration
27
Aq
uaLa
b LITE a
nd Tem
pera
tureA
quaLab
LIT
E
makes
its m
ost accurate
measurem
ents w
hen the temperatures of the sam
ple and instrument are
within 1°C
. If the sample is too w
arm, the “m
ercury” on the anim
ated thermom
eter icon on the left of the screen will fill
the thermom
eter. If the mercury reaches the top of the ther-
mom
eter, the “Sam
ple too hot” screen will appear. If you
get this warning w
hile sampling, rem
ove the sample, place
a lid on the sample cup and w
ait until it has reached ambi-
ent temperature before attem
pting to read again.
If a sample is colder than the am
bient temperature of the
AquaL
ab LIT
E, the accuracy of the reading after 5 m
inutes m
ay be questionable. Wait until the sam
ple's temperature is
similar to that of the A
quaLab L
ITE
.
AquaLab LITE
4. AquaLab LITE O
peration
22
solutions at specific concentrations for constant and accu-rate w
ater activity measurem
ents. They have been pro-
duced under a strict quality-assurance regime, and their
accuracy is verified by quality assurance testing. They are
very accurate, easy to use, and readily available from D
eca-gon D
evices. Most im
portantly, they greatly reduce prepa-ration errors. B
ecause of these reasons, we require using
these standards for the most accurate calibration of your
AquaL
ab LIT
E. T
he calibration standards are shelf-stable for one year.
How
to Verify if C
alibration
Ad
justm
ent Is N
eeded
To verify if a calibration adjustment is needed, do the follow
-ing:
1.C
hoose a verification standard that is close to the water
activity of the sample you are m
easuring. Make sure
that the standard is at ambient tem
perature before you place it into the sam
ple chamber. F
or example, if your
running a sample w
ith a high water activity of around
0.96 aw
use the 0.92 aw
standard for verification. Note:
we do not recom
mend using distilled w
ater to verify perform
ance in the AquaL
ab Lite.
2.E
mpty the w
hole vial of solution into a sample cup and
place it in the AquaL
ab LIT
E's sam
ple chamber.
3.C
lose the lid of the AquaL
ab LIT
E to seal the standard
within the m
easuring chamber.
4.P
ress the middle button from
the main display m
enu to start a reading. T
he final reading should be within
±0.015 aw
of the given value for the chosen salt solu-
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
26
9.D
ecag
on r
ecom
men
ds r
eadi
ng th
e ve
rifi
cati
on s
tand
ard
agai
n in
the
nor
mal
sam
plin
g m
ode.
It
shou
ld r
ead
the
prop
er v
alue
±0.
015a
w f
or y
our
part
icul
ar s
tand
ard.
If
it
does
n’t,
clea
n th
e ch
ambe
r on
ce a
gain
, and
re-
cali
brat
e th
e in
stru
men
t. If
you
sti
ll c
anno
t rea
d th
e pr
oper
val
ue
afte
r re
peat
ing
the
cali
brat
ion,
con
tact
Dec
agon
or
your
lo
cal d
istr
ibut
or f
or a
ssis
tanc
e.
Sam
pli
ng P
reca
utio
ns
1.V
olat
iles
/Hig
h W
ater
. L
ong
expo
sure
to
high
con
cen-
trat
ion
of c
erta
in v
olat
ile
subs
tanc
es o
r to
sam
ples
wit
h w
ater
act
ivit
ies
near
1.0
0 m
ay s
hift
the
sen
sor
cali
bra-
tion
. T
here
fore
, al
way
s re
mov
e sa
mpl
es a
s so
on a
s th
e A
quaL
ab L
ITE
is
fini
shed
sam
plin
g (b
eeps
) to
avo
id
cali
brat
ion
shif
ts t
o th
e se
nsor
. If
a s
ampl
e is
acc
iden
-ta
lly
left
in th
e ch
ambe
r fo
r an
ext
ende
d pe
riod
of
tim
e,
be s
ure
to c
heck
the
cal
ibra
tion
pri
or t
o m
easu
ring
the
ne
xt s
ampl
e.
2.E
thyl
Alc
ohol
. A
quaL
ab L
ITE
's s
enso
r ca
n be
dam
-ag
ed b
y lo
ng-t
erm
exp
osur
e to
hig
h co
ncen
trat
ions
of
ethy
l alc
ohol
. Rea
ding
sam
ples
wit
h al
coho
l con
cent
ra-
tion
s ab
ove
abou
t 10
% c
an s
hift
the
cal
ibra
tion
. If
the
in
stru
men
t is
used
to r
ead
wat
er a
ctiv
ity
of e
xtra
cts
and
othe
r sa
mpl
es w
ith
high
alc
ohol
con
cent
rati
ons,
the
cal -
ibra
tion
sho
uld
be c
heck
ed f
requ
entl
y to
mak
e su
re t
he
read
ings
are
acc
urat
e. E
ffec
ts o
n th
e se
nsor
can
be
redu
ced
by
rem
ovin
g th
e sa
mpl
e im
med
iate
ly
afte
r re
adin
g an
d al
low
ing
the
Aqu
aLab
LIT
E t
o st
and
open
fo
r a
tim
e be
twee
n re
adin
gs to
all
ow th
e al
coho
l to
dif-
fuse
out
of
the
sens
or c
ham
ber,
or b
y m
easu
ring
a c
up
of a
ctiv
ated
cha
rcoa
l.
Aqu
aLab
LIT
E4.
Aqu
aLab
LIT
E O
pera
tion
23
tion
.
5.If
you
r A
quaL
ab L
ITE
is
read
ing
wit
hin
±0.0
15 a
w o
f th
e sa
lt s
olut
ion
then
the
ins
trum
ent
is i
n ca
libr
atio
n.
You
may
beg
in m
easu
ring
the
wat
er a
ctiv
ity
of y
our
sam
ple.
6.If
you
con
sist
entl
y ge
t re
adin
gs t
hat
are
outs
ide
of t
he
wat
er a
ctiv
ity
of y
our
salt
sol
utio
n by
mor
e th
an 0
.015
a w
then
a c
alib
rati
on a
djus
tmen
t is
nece
ssar
y.
NO
TE
: M
ake
sure
tha
t th
e ch
ambe
r, in
frar
ed t
empe
ratu
re
sens
or, a
nd f
ilte
r ar
e cl
ean
befo
re p
roce
edin
g to
adj
ust
the
cali
brat
ion.
A c
onta
min
ated
cha
mbe
r, di
rty
infr
ared
tem
-pe
ratu
re s
enso
r or
fil
ter
may
cau
se t
he s
alt
solu
tion
s to
m
easu
re
outs
ide
of
spec
ific
atio
n.
Ple
ase
revi
ew
the
Aqu
aLab
Se
ries
4T
E
Cle
anin
g Vi
deo
at
http
://
ww
w.a
qual
ab.c
om/e
duca
tion
/ser
ies-
4te-
clea
ning
-vid
eo/ f
or
an e
xam
ple
of h
ow t
o cl
ean
the
sam
ple
cham
ber
and
sen-
sors
. A
ltho
ugh
this
is n
ot s
peci
fica
lly
for
the
Aqu
aLab
Lit
e th
e st
eps
for
clea
ning
are
the
sam
e
Ad
just
ing
the
Cal
ibra
tion
1.O
nce
you
are
cert
ain
that
a
cali
brat
ion
offs
et
has
occu
rred
, us
e th
e 0.
76 a
w s
tand
ard
to c
ondu
ct a
cal
ibra
-ti
on. I
f yo
u do
not
use
the
0.7
6 st
anda
rd t
o ve
rify
you
r L
ITE
s pe
rfor
man
ce,
use
the
stan
dard
clo
sest
to
your
sa
mpl
e’s
a w..
DO
NO
T u
se w
ater
to
cali
brat
e yo
ur
LIT
E. M
ake
sure
the
stan
dard
is a
t am
bien
t tem
pera
ture
be
fore
pou
ring
it
in a
sam
ple
cup
and
plac
ing
it i
n th
e in
stru
men
t for
cal
ibra
tion
.
AquaLab LITE
4. AquaLab LITE O
peration
25
ing screen will appear:
7.F
ollow the on-screen instructions and place a standard
in the chamber. P
ress the center button to start the cali -bration procedure. T
he word “C
AL
” will appear after
the water activity value on the display during the cali-
bration procedure, as shown below
.
NO
TE
: If you decide to stop the calibration procedure, just press the right button to return to the calibration m
enu screen.
8.A
fter 5 minutes, the calibration m
easurement w
ill be com
pleted and the following screen w
ill appear:
Press the center button to accept the new
calibration or press the right button to exit and return to the configu-ration m
enu.
AquaLab LITE
4. AquaLab LITE O
peration
24
2.E
mpty the w
hole vial of solution into a sample cup and
place it in the AquaL
ab LIT
E's sam
ple chamber as
described above.
3.C
arefully close the lid of the AquaL
ab LIT
E to seal the
standard within the m
easuring chamber.
4.E
nter the system m
enu by pressing the right button. O
nce in the system m
enu, press the middle button w
ith the “C
alibrate” function highlighted to enter calibration m
ode. The follow
ing screen will appear:
5.P
ress the left button to scroll down to the calibration
options and press the middle button to select an option.
Selecting “M
anual” will allow
you to choose the spe -cific standard that you are calibrating. If you select “A
uto”, the AquaL
ab LIT
E w
ill automatically deter-
mine w
hich calibration solution (0.250, 0.500, 0.760, 0.920aw
) was inserted, select “D
efaults” to restore the factory calibration settings and begin the verification process again.
6.A
fter selecting the desired option, you will be guided
through the automatic calibration routine. T
he follow-
