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.

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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.
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INTRODUCTION
In Pak istan, wh eat is main ly p ar ticu lar ly cer tain species o f fungi. A t
milled to who le wh eat flour for th e lower mo is ture fung i will no t gro w bu t
produ ction of un le avened f lat br ead at abou t 14% or sligh tly abov e, fung al
lo cally known as “Ch ap a ti” wh ile rest grow th tak es p lace (Hosen ey, 1994).
is used fo r o th er b ak er y p roducts lik e H igh er lipolytic and pro teo lytic
br ead , b iscu its , cakes, pastr ies, pizzas activ ities are related to h igh er mo isture
etc. Th e annu al produ ction of wh eat in con ten t, which furth er lead to loss in
Pak istan is 19.23 milli on ton es and th e nu tr ien ts (pro tein and fat) and
area cov ered is 8.69 millio n h e ctares produ ction of mor e FFA r esu lting in
(Anon . 2003). inf er ior sensor y char acter is tics.
Mo is tur e con ten t of f lour is In mod ern age, food pack ag ing
v er y impor ta n t reg ard ing its sh e lf lif e, h as be co me v er y imp orta n t b ec ause of
l o w e r the f lo u r mo i s tur e , the b e t te r i ts pro tection of the produ ct fro m
sto rag e stab ility. Th e d e terio ration of c o n ta mi n a t ion b y ma c r o & mic r o -
b ak ing qu ality is also less at lower 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
mo isture con ten t wh ich can be cred ited fro m lo ss or g a in of mo isture,
to retarded resp iration and activ ity of shield ing the produ ct fro m ox ygen and
micr oorg an isms ( S taudt and Zeig ler, to facilitate h and ling (Ball, 1960).
1973) Good packag ing actually serv es
Mo is tur e is an impo r tan t f ac tor t w o p u r p o se s, w h ich a r e e ss en t ia l l y
in con tro lling gr ain infestation. Insects te chn ica l and pr es en ta tion a l. T echnic a l
th at liv e on stor ed gr ains and th eir a sp ec t s in p a ck ag ing a im t o e x ten d t h e
produ cts depend upon th e mo is tu re shelf lif e of the food b y b e tter
supply. Generally, mo istur e con ten t of pro tection fro m all th e h azard s dur ing
9% or low er restr icts inf estation. s to rag e. Pres en ta tiona l a sp ec ts are no t
Mo is ture is also of great imp ortance c o n c ern ed w i th she lf l i f e b u t s u ch
for th e saf e s to rag e of ce re a ls and th e ir p ack ag ing in cre a se s sa le s b y cr e a ting a
produ cts regard ing micr oorg an isms,

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b r and i ma g e t h a t th e b u y er ins t an t l y and due to w eath er cond itions it is
r ecogn izes (Peter and Ax tell, 1993). in ev itab le to exp lor e prop er pa ck ag ing
P re sen tly p ack ag ing ma te r ia ls ma terial & mo isture con ten t to ov er
b e ing us ed in P ak is tan for f lou r a re co me ex is ting d ilemma .
ju te, co tton and po lyprop ylene. Th ese Th e presen t proj ect was d esign ed
p ack ag es do no t pro tect the wh eat flour 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
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 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 ests, microb es, sand, dust and p ack ag ing ma te r ia l for s af e s torage and
env iron mental mo isture. to find ou t mo st su itab le co mb ination
In climate lik e Pak istan th e of mo is ture con ten t and pa cka g ing
shelf lif e of f lour is a ser iou s prob lem ma terial for flou r stab ility.
p ack ag ing to ob tain wh ea t f lou r
MATERIALS AND samp les hav ing d ifferen t mo istu re
METHODS con ten t i. e. 13.5 , 13 , 12, 11, 10 and 9%
W heat Po lyprop ylene b ags and ( Tab l e 1) .
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 Moisture content of flour after Packaging ( %)
Treatment
of wheat (%) tempered Wheat ( %) Polypropylene bags Multiwall paper bags
T1 8.4 17.50 13.51 13.51
T2 8.4 17.00 13.02 13.02
T3 8.4 16.00 12.01 12.01
T4 8.4 15.00 11.01 11.01
T5 8.4 14.00 10.02 10.02
T6 8.4 13.00 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 a nd 60 d a ys u s ing th e me th od d esc r ibed b y

Who le- Wheat Flour D uring Storage Ben ek e (1962).
Prox imate Ana ly s is I ns e ct Inf esta t io n
E a ch tr eatme n t w as an a lyz ed In se c t egg s in wh ea t f lour w ere
for tn igh tly up to 60 d a ys for mo is tu re, ob serv ed b y iod in e me thod and in se c t ha ir s
crude pro tein, crud e f a t, crud e f ib er, to tal w ere d e termin ed by clov e o il me th od
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 for tn igh tly for two mo n th s of s torag e,
pro cedu res d escr ib ed in AA CC (2000). accord ing to me thod descr ib ed in AA CC
Estimat ion of Iron (2000) . V isual ob serv ation was also
I r o n con ten t w a s e s t i ma t e d w i th th e c ar r ied ou t to ob s erve in se c t larv ae and
in terval of 15 d ays up to 2 mon ths b y a d u l ts.
u sing spectropho to me ter accord ing to S tat ist ica l Ana ly s is
me th od d escr ib ed in AOA C (1990) . Th e d a t a o b t a ined f r o m e ac h
Count ing of Mo lds treatmen t was subjected to statistical
Coun ting of mo ld s was done by 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
s er ia l d ilu tion or ag ar p la te techn iqu e on w ith in the tr ea tme n ts, p ack ag ing ma te r ia l
Sabour aud agar me d ium at 0 , 15, 30 , 45 & stor ag e in tervals and in ter actions amo ng

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th es e p ar a me ter s a s d es cr ib ed b y s te e l e t mo istur e con ten t dur ing stor age were due
a l. (1997). 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
R ESU LTS AND D ISCUSSIONS f ind ing s of Reh man and Sh ah (1999) and
Prox imate Co mposition of Who le-Whea t K irk and Saw yer (1991).
F lo u r D u r in g S t o ra g e Th e r e su l ts p er t a in in g t o th e cru d e
Th e mo is tur e con ten t w as aff ec ted pro tein con ten t show ed a d e cr easing tr end
sign ific an tly du e to sto rag e, treatmen ts, w ith s tor age . A mong th e tre a tme n ts th e
p ack ag ing a nd th e ir in tera c tion (T ab le d ecr e as e wa s mo r e in tr e a tme n ts h av ing
2,3 ,4). h igh er mo is tu re b ec aus e h igh er mo is tur e
Th e mo i s tur e c o n ten t o f T 1 , T 2 , T 3 , c on ten t in wh ea t f lou r f avor ed pro teo lytic
a n d T 4 d e cre a sed w ith s to rag e p er iod up to activ ity. A fter 45 days th e crud e pro tein o f
45 d a ys and th en in cre as ed af terw ard s. Th e th e samp les hav ing h igh er mo isture levels
in itial decrease was du e to rela tiv e ly low i n cre a sed d u e to ins ec t i n f es t a t ion an d
rela tiv e humid ity in atmo sphere. After 45 micr ob ial grow th. Ch ang es in pro tein in
d a ys of stor age, h igher r e lative hu mid ity p aper bag s w er e a lso low er th an in
in a tmosph er e c au sed the f lour mo is tu re to po lyprop ylen e bag s. Th ese r esu lts ar e in
in cre a se up to end of s tor age . How ev er, the 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
c hang es we re mo r e in sa mp le s h av ing b y L ee l av a th i e t a l. (1984) and Up adh yay
h igh er in itial mo isture con ten t. Th e (1994) .
mo i s t u r e in T 5 and T 6 increased throughou t Th e cru d e f a t d e cr e as ed d u r ing the
th e stor ag e p er iod. This incr ease w as du e sto rag e per iod. The decr ease ma y b e
to th eir lowe r in i t i a l mo i stur e c o n te n t . attribu ted to th e lipo lytic activ ity o f
Be tw e en th e p a ckag ing ma te r ia ls, th e f lour e nz yme s i.e . lip as e and lipox id as e. Th e
in p ap er b ags showed less change in 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
mo is tur e c on ten t. Th es e ch ang es in th an in po lyprop ylen e.

Table 2 Mean values for effect of treatments on proximate composition, total

iron, & colonies of molds
Treatments Mo is tu re C rud e C rud e C rud e Tota l NFE Tota l Co lonies
c o n t ent p ro t e in Fa t F i be r A sh ( %) I ro n of
( %) ( %) ( %) ( %) ( %) mg /Kg Moulds
T1 11.84 10.95 2.06 2.49 1.72 69.78 40.17 709
T2 11.67 11.10 2.07 2.48 1.71 69.94 40.17 641
T3 11.33 11.30 2.08 2.49 1.71 70.27 40.06 560
T4 10.95 11.37 2.09 2.49 1.70 70.72 40.17 463
T5 10.57 11.40 2.09 2.50 1.7 71.03 40.21 390
T6 9.79 11.42 2.10 2.49 1.7 71.88 40.19 328
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.
Table 3 Mean values for effect of storage period on proximate composition,
total iron, & colonies of molds
Storag e Mo isture C rud e C rud e C rud e Tota l NFE Tota l Co lonies
P e r io d c o n t ent p ro t e in Fa t F i be r A sh ( %) I ro n o f M o u ld s
(Day s) ( %) ( %) ( %) ( %) ( %) mg /Kg
0 11.43 11.93 2.12 1.71 1.72 70.01 41.26 152
15 11.16 11.80 2.10 2.5 1.71 70.44 40.72 241
30 10.86 11.72 2.08 2.49 1.70 70.83 40.20 575
45 10.74 11.60 2.07 2.49 1.70 70.92 39.56 685
60 10.83 11.49 2.05 2.49 1.70 70.80 39.07 926

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Table 4 Mean values for effect of packaging material on proximate
composition, total iron, & colonies of molds
Packaging Mo isture C rud e C rud e C rud e Tota l NFE Tota l Co lonies
Material c o n t ent p ro t e in Fa t F i be r A sh ( %) I ro n of
( %) ( %) ( %) ( %) ( %) mg /Kg Moulds
Polypropylene
10.97 11.79 2.08 2.49 1.70 70.56 40.14 521
bags
Paper bags 10.98 12.04 2.09 2.49 1.70 70.63 40.15 494

Table 5 Mean values for effect of storage, packaging material and treatments on the
insect infestation in whole-wheat flour
Storage Period
Treatment Packaging Material 0 days 15 Days 30 Days 45 Days 60 Days
- - + ++ +++
Poly propylene bags
T1
Multiwall paper bags - - - - +

Poly propylene bags - - + ++ +++

T2
Multiwall paper bags - - - - +

Poly propylene bags - - - + ++

T3
Multiwall paper bags - - - - -

Poly propylene bags - - - - +

T4
Multiwall paper bags - - - - -

Poly propylene bags - - - - --

T5
Multiwall paper bags - - - - -

Poly propylene bags - - - - -

T6
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

P ap er b ag s prov id ed more (1997) and Misfa e t a l. (2000) who also

pro tec tion ag a ins t th e ox yg en in th e ob serv ed r edu ction of iron du r ing stor age.
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 .
Co lony Count of Mo lds
Th e resu lts closely resemb le th e resu lts
Th e r esu lts for co lon ies of dur ing
ob tained b y Har id a s (1983) and Leelav ath i
s to rag e show ed tha t th e mo ld s d iff er ed
e t a l. (1984) who also r epor ted th e similar
sign ific an tly with resp ect to treatmen ts,
tr end of decr ease in crude fat dur ing
s to rag e per iod p ack ag ing ma te ria l and
sto rag e. Crud e f iber and ash were no t
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
aff ected during th e study.
( Tab le 2,3,4). H igh er mo isture con ten t
I ro n C o nt en t
f avor ed mold grow th . Mo ld grow th w as
T o ta l iron de cre a sed w ith s tor age
also less in p aper b ags th an in
p er iod ; how ever , packag ing ma ter ial,
po lyprop ylen e b ags.
treatmen ts and in teraction d id no t h ave
Re s u lts of pr es en t inve s tigation ar e
imp act upon th is d e cr ease(Tab le 2 ,3,4) .
co mp arab le w ith those found b y Both ast e t
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.

4
a l. (1991 ) and Up adh yay e t a l. (1994) who prop er ties of wheat f lour and co rn
also seen similar trend dur ing stor ag e. me a l d u r in g s to r age . C er ea l
Chem.42 (3) : 187 -190.
I ns e ct Inf esta t io n
D in, S.A. 1998. Chemi cal and Fun c tional
In se c t infe s ta tion in d iff er ent
Proper ties of A tta Pr epared b y
treatmen ts in both p a ckag ing was
D if f e r e n t R o l le r F lo u r M ills and
mo n itor ed by observ ing insect egg s, in sect
Ch ina Mills. M.Sc. (Hon s.) Thesis ,
h a ir mic ro sc op ic a lly and adu lts by v isu a l
D epar tme n t of Food Techno logy,
e x a mi n a t io n . The r esul t s o b t a in ed w i th
Un iv ers ity of Agr icu ltur e,
r ega rd to in se c t in fe s ta tion ind icate d th a t
F a is a labad .
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 Ho sen e y, R. C. 1994. Pr in cip les of Cereal
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 Science and Techno logy. 2nd
th an po lyprop ylene b ags as. Similar r e sults e d . A m. A s so c. o f Ce r e a l Ch e m.
w ere found b y Leelavath i e t a l. (1984) and In c., S t. P au l, M in n e so t a , U SA.
Up adh yay et a l. (1994) .
K irk, S.R. and R. Saw yer. 1991. Pearson’ s
Co mpo s ition and An alys is of
CONC LU SION
Food s. Add ison -W esley Long ma n
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 Ltd . Ed inburg Gate, H ar low,
10% mo isture con ten t in mu ltiwall kraft Eng land.
p aper bag s prov id ed ma x imu m pro tection L e e lav a th i, k . , P . H . Ra o , D . I n d r a n i and
again s t in sect inf estation and mo ld grow th. S. R. Shurp a lek ar. 1984. Ph is co-
Th e ph ysico- chemical ch anges w er e also c h e mi c a l c h an g e s in w h o l e w h ea t
lower in th ese treatme n ts. Mu ltiwall kraft f lo u r ( A t ta ) a n d r e s u l t a n t a t ta
p aper bag s w ere found to b e eff e ctiv e dur ing stor ag e. J. Food Sci. Tech .
again s t mould grow th , in sect inf estation,
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and mo isture chang es. So the f lour h av ing Shu rpalekar. 1983. Co mp ar ative
9% mo is ture con ten t (T 6 ) w a s proved to b e stud ies on atta (who le wh eat f lour)
mo st appropr iate r egarding th e shelf life of and r esu ltan t atta a by-produ ct of
wh eat f lour. 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.
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