Internet Journal of Food Safety V. 4, 1-6
Effect OF Moisture and Packaging on the Shelf Life of
Wheat Flour
Masood Sadiq Butt, Muhammad Nasir, Saeed Akhtar and Kamran Sharif.
Institute of Food Science & Technology, University of Agriculture, Faisalabad.
______________________________________________________________
ABSTRACT
T e mp er ing of th e whe at s a mp les w ith d iff er en t a mo un ts of w a ter wa s don e to
ob ta in f lour tr e a tme n ts h av ing d ifferen t mo isture levels i.e. T 1 (13.5%), T 2 (13%), T 3
(12 %), T 4 (11%), T 5 (10%) and T 6 (9 %) after millin g . These tr eatmen ts were sep arately
p ack ed in po lyprop ylene and p ap er bag s. Dur ing the storage p er iod of 60 d a ys, each
tr eatmen t in bo th polyprop ylene and p aper bag s was evalu a ted for prox imate
co mposition, insect inf estation, mo ld g row th and to tal iron . Th e crude pro tein and crude
f a t d ec re as ed w i th s tor ag e p er iod. Mo is tur e con t en t ( m. c) i n T 1 (13.5% m. c.), T 2 (13 %
m. c . ) and T 3 (12 % m. c.) d ecr e ase d. Ch ang es w er e minimu m in T 4 (11% m. c.) and
in cre a s ing tr end wa s s ee n in T 5 (10% m. c.) and T 6 (9 % m. c.) . Th e chang es w er e mor e in
po lyprop ylen e than in paper b ag s. Chang e s in ash and f ib er w er e non sign if ic an t dur ing
th e stud y. In sect inf estation and mo u ld g rowth w er e also f avor ed by h igh er mo is tu re
con ten t of flour. Pap er p ack ag ing w as found to b e su itab le ag ainst insect inf estation and
mo u ld growth. To tal iron also show ed a decreasing trend w ith storage p er iod. Low er
f lour mo i s tur e ( T 6 = 9%) and p aper p ack ag ing w er e found to be su itab le for sto rag e
stab ility & long er shelf life of wheat flou r.
______________________________________________________________
INTRODUCTION
In Pak istan, wh eat is main ly
milled to who le wh eat flour for th e
produ ction of un le avened f lat br ead
lo cally known as “Ch ap a ti” wh ile rest
is used fo r o th er b ak er y p roducts lik e
br ead , b iscu its , cakes, pastr ies, pizzas
etc. Th e annu al produ ction of wh eat in
Pak istan is 19.23 milli on ton es and th e
area cov ered is 8.69 millio n h e ctares
(Anon . 2003).
Mo is tur e con ten t of f lour is
v er y impor ta n t reg ard ing its sh e lf lif e,
l o w e r the f lo u r mo i s tur e , the b e t te r i ts
sto rag e stab ility. Th e d e terio ration of
b ak ing qu ality is also less at lower
mo isture con ten t wh ich can be cred ited
to retarded resp iration and activ ity of
micr oorg an isms ( S taudt and Zeig ler,
1973)
Mo is tur e is an impo r tan t f ac tor
in con tro lling gr ain infestation. Insects
th at liv e on stor ed gr ains and th eir
produ cts depend upon th e mo is tu re
supply. Generally, mo istur e con ten t of
9% or low er restr icts inf estation.
Mo is ture is also of great imp ortance
for th e saf e s to rag e of ce re a ls and th e ir
produ cts regard ing micr oorg an isms,
p ar ticu lar ly cer tain species o f fungi. A t
lower mo is ture fung i will no t gro w bu t
at abou t 14% or sligh tly abov e, fung al
grow th tak es p lace (Hosen ey, 1994).
H igh er lipolytic and pro teo lytic
activ ities are related to h igh er mo isture
con ten t, which furth er lead to loss in
nu tr ien ts
(pro tein
and
fat)
and
produ ction of mor e FFA r esu lting in
inf er ior sensor y char acter is tics.
In mod ern age, food pack ag ing
h as be co me v er y imp orta n t b ec ause of
pro tection
of
the
produ ct
fro m
c o n ta mi n a t ion b y ma c r o & mic r o o r g an is ms a n d th e ir f i l t h , p r e v e n t i on
fro m lo ss or g a in of mo isture,
shield ing the produ ct fro m ox ygen and
to facilitate h and ling (Ball, 1960).
Good packag ing actually serv es
t w o p u r p o se s, w h ich a r e e ss en t ia l l y
te chn ica l and pr es en ta tion a l. T echnic a l
a sp ec t s in p a ck ag ing a im t o e x ten d t h e
shelf lif e of the food b y b e tter
pro tection fro m all th e h azard s dur ing
s to rag e. Pres en ta tiona l a sp ec ts are no t
c o n c ern ed w i th she lf l i f e b u t s u ch
p ack ag ing in cre a se s sa le s b y cr e a ting a
1
b r and i ma g e t h a t th e b u y er ins t an t l y
r ecogn izes (Peter and Ax tell, 1993).
P re sen tly p ack ag ing ma te r ia ls
b e ing us ed in P ak is tan for f lou r a re
ju te, co tton and po lyprop ylene. Th ese
p ack ag es do no t pro tect the wh eat flour
p r o p er l y f r o m c o n t a mi n a t ion b y in se c t
p ests,
microb es,
sand,
dust
and
env iron mental mo isture.
In climate lik e Pak istan th e
shelf lif e of f lour is a ser iou s prob lem
and due to w eath er cond itions it is
in ev itab le to exp lor e prop er pa ck ag ing
ma terial & mo isture con ten t to ov er
co me ex is ting d ilemma .
Th e presen t proj ect was d esign ed
t o e x t e n d th e s h e lf l i f e o f f lo u r b y
d e ter mi n i n g t h e p ro p e r mo i s tur e a n d
p ack ag ing ma te r ia l for s af e s torage and
to find ou t mo st su itab le co mb ination
of mo is ture con ten t and pa cka g ing
ma terial for flou r stab ility.
p ack ag ing to ob tain wh ea t f lou r
samp les hav ing d ifferen t mo istu re
con ten t i. e. 13.5 , 13 , 12, 11, 10 and 9%
( Tab l e 1) .
MATERIALS
AND
METHODS
W heat Po lyprop ylene b ags and
mu l t i w a l l ( 3 l a yer s ) k r a f t p ap e r b ag s
w ere pu rchased fro m th e local ma rk et
of Fa is a lab ad.
P r epa rat ion o f Who le Wh eat Flou r
Sa mp les
T e mp er ing of wh ea t s amp le s
w as done at d ifferen t mo istur e lev e ls
wh ich were fo llowed b y milling and
Moisture content
Moisture content of
Treatment
of wheat (%)
tempered Wheat ( %)
8.4
17.50
T1
8.4
17.00
T2
8.4
16.00
T3
8.4
15.00
T4
8.4
14.00
T5
8.4
13.00
T6
Moisture content of flour after Packaging ( %)
Polypropylene bags Multiwall paper bags
13.51
13.51
13.02
13.02
12.01
12.01
11.01
11.01
10.02
10.02
9.00
9.00
Table 1. Different Treatments Used In Study
Ana ly s is of D iff e re nt Treat m en ts of
Who le- Wheat Flour D uring Storage
Prox imate Ana ly s is
E a ch
tr eatme n t
w as
an a lyz ed
for tn igh tly up to 60 d a ys for mo is tu re,
crude pro tein, crud e f a t, crud e f ib er, to tal
a sh , and N F E b y f o l lo w i n g th e ir r es p e c t ive
pro cedu res d escr ib ed in AA CC (2000).
Estimat ion of Iron
I r o n con ten t w a s e s t i ma t e d w i th th e
in terval of 15 d ays up to 2 mon ths b y
u sing spectropho to me ter accord ing to
me th od d escr ib ed in AOA C (1990) .
Count ing of Mo lds
Coun ting of mo ld s was done by
s er ia l d ilu tion or ag ar p la te techn iqu e on
Sabour aud agar me d ium at 0 , 15, 30 , 45
2
a nd 60 d a ys u s ing th e me th od d esc r ibed b y
Ben ek e (1962).
I ns e ct Inf esta t io n
In se c t egg s in wh ea t f lour w ere
ob serv ed b y iod in e me thod and in se c t ha ir s
w ere d e termin ed by clov e o il me th od
for tn igh tly for two mo n th s of s torag e,
accord ing to me thod descr ib ed in AA CC
(2000) . V isual ob serv ation was also
c ar r ied ou t to ob s erve in se c t larv ae and
a d u l ts.
S tat ist ica l Ana ly s is
Th e d a t a o b t a ined f r o m e ac h
treatmen t was subjected to statistical
a n a l y s is to d e ter mi n e an a l ys i s o f v a r ian c e
w ith in the tr ea tme n ts, p ack ag ing ma te r ia l
& stor ag e in tervals and in ter actions amo ng
th es e p ar a me ter s a s d es cr ib ed b y s te e l e t
a l. (1997).
mo istur e con ten t dur ing stor age were due
to the h ygro scop ic prop er ties o f f lour. The
r esu l t s a r e c o l lab o r a te d b y the e ar l i er
f ind ing s of Reh man and Sh ah (1999) and
K irk and Saw yer (1991).
Th e r e su l ts p er t a in in g t o th e cru d e
pro tein con ten t show ed a d e cr easing tr end
w ith s tor age . A mong th e tre a tme n ts th e
d ecr e as e wa s mo r e in tr e a tme n ts h av ing
h igh er mo is tu re b ec aus e h igh er mo is tur e
c on ten t in wh ea t f lou r f avor ed pro teo lytic
activ ity. A fter 45 days th e crud e pro tein o f
th e samp les hav ing h igh er mo isture levels
i n cre a sed d u e to ins ec t i n f es t a t ion an d
micr ob ial grow th. Ch ang es in pro tein in
p aper bag s w er e a lso low er th an in
po lyprop ylen e bag s. Th ese r esu lts ar e in
c l o s e agr e eme n t w i th th e r e su l ts o b t a ined
b y L ee l av a th i e t a l. (1984) and Up adh yay
(1994) .
Th e cru d e f a t d e cr e as ed d u r ing the
sto rag e per iod. The decr ease ma y b e
attribu ted to th e lipo lytic activ ity o f
e nz yme s i.e . lip as e and lipox id as e. Th e
l i p o ly t ic a c t i v i t y w a s low e r in p a p e r b ag s
th an
in
po lyprop ylen e.
R ESU LTS AND D ISCUSSIONS
Prox imate Co mposition of Who le-Whea t
F lo u r D u r in g S t o ra g e
Th e mo is tur e con ten t w as aff ec ted
sign ific an tly du e to sto rag e, treatmen ts,
p ack ag ing a nd th e ir in tera c tion (T ab le
2,3 ,4).
Th e mo i s tur e c o n ten t o f T 1 , T 2 , T 3 ,
a n d T 4 d e cre a sed w ith s to rag e p er iod up to
45 d a ys and th en in cre as ed af terw ard s. Th e
in itial decrease was du e to rela tiv e ly low
rela tiv e humid ity in atmo sphere. After 45
d a ys of stor age, h igher r e lative hu mid ity
in a tmosph er e c au sed the f lour mo is tu re to
in cre a se up to end of s tor age . How ev er, the
c hang es we re mo r e in sa mp le s h av ing
h igh er in itial mo isture con ten t. Th e
mo i s t u r e in T 5 and T 6 increased throughou t
th e stor ag e p er iod. This incr ease w as du e
to th eir lowe r in i t i a l mo i stur e c o n te n t .
Be tw e en th e p a ckag ing ma te r ia ls, th e f lour
in p ap er b ags showed less change in
mo is tur e c on ten t. Th es e ch ang es in
Table 2
Mean values for effect of treatments on proximate composition, total
iron, & colonies of molds
Treatments
T1
T2
T3
T4
T5
T6
Mo is tu re
c o n t ent
( %)
11.84
11.67
11.33
10.95
10.57
9.79
C rud e
p ro t e in
( %)
10.95
11.10
11.30
11.37
11.40
11.42
C rud e
Fa t
( %)
2.06
2.07
2.08
2.09
2.09
2.10
C rud e
F i be r
( %)
2.49
2.48
2.49
2.49
2.50
2.49
Tota l
A sh
( %)
1.72
1.71
1.71
1.70
1.7
1.7
NFE
( %)
69.78
69.94
70.27
70.72
71.03
71.88
T 1 = 13.5% m.c.
T 2 = 13% m.c.
T 3 = 12% m.c.
T 4 = 11% m.c.
T 5 = 10% m.c.
T 6 = 9% m.c.
Tota l
I ro n
mg /Kg
40.17
40.17
40.06
40.17
40.21
40.19
Co lonies
of
Moulds
709
641
560
463
390
328
Mean values for effect of storage period on proximate composition,
total iron, & colonies of molds
Table 3
Storag e
P e r io d
(Day s)
0
15
30
45
60
Mo isture
c o n t ent
( %)
11.43
11.16
10.86
10.74
10.83
C rud e
p ro t e in
( %)
11.93
11.80
11.72
11.60
11.49
C rud e
Fa t
( %)
2.12
2.10
2.08
2.07
2.05
C rud e
F i be r
( %)
1.71
2.5
2.49
2.49
2.49
3
Tota l
A sh
( %)
1.72
1.71
1.70
1.70
1.70
NFE
( %)
70.01
70.44
70.83
70.92
70.80
Tota l
I ro n
mg /Kg
41.26
40.72
40.20
39.56
39.07
Co lonies
o f M o u ld s
152
241
575
685
926
Table 4
Mean values for effect of packaging material on proximate
composition, total iron, & colonies of molds
Packaging
Material
Polypropylene
bags
Paper bags
Table 5
Mo isture
c o n t ent
( %)
C rud e
p ro t e in
( %)
C rud e
Fa t
( %)
C rud e
F i be r
( %)
Tota l
A sh
( %)
NFE
( %)
Tota l
I ro n
mg /Kg
Co lonies
of
Moulds
10.97
11.79
2.08
2.49
1.70
70.56
40.14
521
10.98
12.04
2.09
2.49
1.70
70.63
40.15
494
Mean values for effect of storage, packaging material and treatments on the
insect infestation in whole-wheat flour
Treatment
Packaging Material
T1
Poly propylene bags
Multiwall paper bags
T2
Poly propylene bags
Multiwall paper bags
T3
Poly propylene bags
Multiwall paper bags
T4
T5
Storage Period
0 days 15 Days 30 Days 45 Days 60 Days
Poly propylene bags
Multiwall paper bags
Poly propylene bags
Multiwall paper bags
-
-
+
++
+++
-
-
-
-
+
-
-
+
++
+++
-
-
-
-
+
-
-
-
+
++
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
--
-
-
-
-
-
Poly propylene bags
Multiwall paper bags
+++ = Infestation with the presence of live insects
++= Infestation with the formation of lumps
+ = Slight infestation with the formation of lumps - = No Infestation
T6
(1997) and Misfa e t a l. (2000) who also
ob serv ed r edu ction of iron du r ing stor age.
P ap er
b ag s
prov id ed
more
pro tec tion ag a ins t th e ox yg en in th e
a t mo sph er e t o co me i n c o n ta c t w i th f lo u r .
Th e resu lts closely resemb le th e resu lts
ob tained b y Har id a s (1983) and Leelav ath i
e t a l. (1984) who also r epor ted th e similar
tr end of decr ease in crude fat dur ing
sto rag e. Crud e f iber and ash were no t
aff ected during th e study.
I ro n C o nt en t
T o ta l iron de cre a sed w ith s tor age
p er iod ; how ever , packag ing ma ter ial,
treatmen ts and in teraction d id no t h ave
imp act upon th is d e cr ease(Tab le 2 ,3,4) .
R e su l ts ar e c o l lab o r a t ed w i th Rub in e t a l.
Co lony Count of Mo lds
Th e r esu lts for co lon ies of dur ing
s to rag e show ed tha t th e mo ld s d iff er ed
sign ific an tly with resp ect to treatmen ts,
s to rag e per iod p ack ag ing ma te ria l and
i n t er a c t ion b e twe en a ll t h es e p a r a me t e r s
( Tab le 2,3,4). H igh er mo isture con ten t
f avor ed mold grow th . Mo ld grow th w as
also
less
in
p aper
b ags
th an
in
po lyprop ylen e b ags.
Re s u lts of pr es en t inve s tigation ar e
co mp arab le w ith those found b y Both ast e t
4
prop er ties of wheat f lour and co rn
me a l
d u r in g
s to r age .
C er ea l
Chem.42 (3) : 187 -190.
a l. (1991 ) and Up adh yay e t a l. (1994) who
also seen similar trend dur ing stor ag e.
I ns e ct Inf esta t io n
In se c t
infe s ta tion
in
d iff er ent
treatmen ts
in
both
p a ckag ing
was
mo n itor ed by observ ing insect egg s, in sect
h a ir mic ro sc op ic a lly and adu lts by v isu a l
e x a mi n a t io n . The r esul t s o b t a in ed w i th
r ega rd to in se c t in fe s ta tion ind icate d th a t
inf es ta tion w as favor ed b y h igh er mo is tur e
in f lou r (Tab le 5 ). Pap er b ags prov id ed
mo r e p r o t e ct i o n aga in s t i n se c t inf es t a t ion
th an po lyprop ylene b ags as. Similar r e sults
w ere found b y Leelavath i e t a l. (1984) and
Up adh yay et a l. (1994) .
D in, S.A. 1998. Chemi cal and Fun c tional
Proper ties of A tta Pr epared b y
D if f e r e n t R o l le r F lo u r M ills and
Ch ina Mills. M.Sc. (Hon s.) Thesis ,
D epar tme n t of Food Techno logy,
Un iv ers ity
of
Agr icu ltur e,
F a is a labad .
Ho sen e y, R. C. 1994. Pr in cip les of Cereal
Science and Techno logy.
2nd
e d . A m. A s so c. o f Ce r e a l Ch e m.
In c., S t. P au l, M in n e so t a , U SA.
K irk, S.R. and R. Saw yer. 1991. Pearson’ s
Co mpo s ition
and
An alys is
of
Food s. Add ison -W esley Long ma n
Ltd .
Ed inburg
Gate,
H ar low,
Eng land.
CONC LU SION
Th e p re sen t s tud y r ev eals tha t T 6
h av ing 9% mo istur e con ten t and T 5 h av ing
10% mo isture con ten t in mu ltiwall kraft
p aper bag s prov id ed ma x imu m pro tection
again s t in sect inf estation and mo ld grow th.
Th e ph ysico- chemical ch anges w er e also
lower in th ese treatme n ts. Mu ltiwall kraft
p aper bag s w ere found to b e eff e ctiv e
again s t mould grow th , in sect inf estation,
lipo lytic activ ities, pro teo lytic activ ities
and mo isture chang es. So the f lour h av ing
9% mo is ture con ten t (T 6 ) w a s proved to b e
mo st appropr iate r egarding th e shelf life of
wh eat f lour.
L e e lav a th i, k . , P . H . Ra o , D . I n d r a n i and
S. R. Shurp a lek ar. 1984. Ph is coc h e mi c a l c h an g e s in w h o l e w h ea t
f lo u r ( A t ta ) a n d r e s u l t a n t a t ta
dur ing stor ag e. J. Food Sci. Tech .
H ar ida s, P. R. , K. Lee lav a th i and S . R.
Shu rpalekar.
1983. Co mp ar ative
stud ies on atta (who le wh eat f lour)
and r esu ltan t atta a by-produ ct of
r o l l e r f lo u r mi l l i n g i n d u s t r y. J .
Food Sci. Tech . 20(1) : 5-8.
REFERENCES
AA CC.
Misfa. H., S. Reh man , N . Hu ma and F.
Raf iq. 2000. Stud ies on wheat atta
fortif ied with elemen tal iron u sed
for chap ati produ ction. Pak. J. Food
Sci. 10(3-4): 5-7 .
2000. Approv ed Method s of
A me r i can A sso c ia t io n o f Ce r e al
Che mis ts . A m. A sso c. of Cer eal
Che m. , In c. S t. P au l. Minn eso ta.
Peter, F. and B. Ax tell. 1993. Appropr iate
Food Packag ing. Pub l. Tr an sfer of
T e chno log y
for
De ve lop me n tA msterdam, In tern ation a l Labour
off ice, G eneva.
Anon ymou s. 2003 . Econo mic Survey.
Gov t.
of
Pak istan,
Econo mic
Adv isor’s W ing, F in an ce D iv ision,
I s la ma b ad.
Ball, C. O. 1960. H er e are eff ects on co lo r
c hang es in p ack ag ing of fr e sh me a t
c u ts. Na tl. P rov is ion al 143 (47 ):
10-12.
Reh man , Z. U. and W . H. Sh ah. 1999.
Bioch e mical ch anges in wh eat
dur ing
s to rag e
at
thr ee
temp eratur es.
Plan t
Food
for
Hu ma n Nu tri. 54 (2) : 109-117.
Ben ek e, E. S. 1962 . Med ical Myco log y.
Lab. Manual Bu rgess Pub . Co .
Minneapo lis, Minn eso ta. 21 : 68-71.
Rub in, S. H. , A. E mis i and L . S c a lp i.
1977. Micronu tr ien t add ition to
c er e a l g r a in p r o d u c ts . Ce r e a l Ch e m.
54(4) : 895-903.
Bo tha s t, R.J ., R.A . And erson , K. W arne r
and W . F. Kwo lek. 1991. Eff ects of
mo i s t u r e
and
te mp e r a tu r e
on
micr ob io logical
and
sen sor y
S a mu e ls , R. a n d R. Mo d g i l. 1 9 9 9 . P h y s ico c h e mi c a l cha n g e s in in se c t inf es t ed
5
Staud t,
wh ea t s to red in d if fere n t s tor age
structur es. Journal o f Food Sci. &
Tech., 36 (5) : 479 -482.
S ta tis tic s. A b io me tr ica l Appro a ch,
3 r d Ed. M cGr aw H i l l Bo o k Co. Inc.
N ew York .
E. and Zieg ler. 1973. Flou r
C h e mi s t r y 1 s t ED. Bhu ler Bro th er s
Ltd ., Eng in eer ing W ork s 9240
U zw i l, Sw i te rz er l and.
Up adh ya y, R. K ., M. Th ang ar aj and P. k .
Jaiswal. 1994. Stor ag e stud ies of
s uji in d iffe ren t p a ckag es. Journ al
of Food Sci. & Tech., 31 (6 ) : 494496.
S t e e l, R ., J . H. Torr ie , and D. D i cke y .
1997. Pr in cip les and Pro cedu res of
6