Asian J. Dairy Res., 1982, 1 (2) : 97-103.
CHANGES IN THE PHYSICO-CHEMICAL PROPERTIES OF
BUTTER POWDER FROM BUFFALO MILK DURING
STORAGE"
Sitaram Prasad l Rnd S.K.Gupta
Dairy Technology Division, National Dairy Research Institute, Karnal. 1320D1, India
ABSTRACT
Butter powder from buffalo milk (BBP) was manufactuttld and stored in tin
'C(lntainers (under nitrogen) and polyethylene bags (PE) at 5 ± 2"C and 30 ± loe for
One year to study the changes in the physico-chemical properties. No change was
observed in the moisture content of the product packed in tins while there was
substantial increase in the Olle packed in ,PE bags. Apparently little but statistically significant change occurred in free fatty acids content and acidity level of the
product during storage. A significant increase in the peroxide and TBA values
was o·bserved. The deterioration was more extensive in the product contained in
FE bags particularly at 30'C, The free. fat and expressible fat contents also inc'reased with an increase in period and temperature of storage and the increase was
greater in PE bags as compared to fins. A gradual decrease in fiowability
was observed.
INTRODUCTION
When manufactured, butter (salted or unsalted) requires low temperature
storage to prevent spoilage and incorporation of objectionable flavours. It is not
only less convenient to handle but also poses problems during packaging and
handling for sale as tabk butter or when it is beingemu!$ined for recombination.
The drying process reduces the volume of milk 'solids for storage and increases the shelf life of an otherwise per'ishiible commodity. In the dried form
there is also ease in transportation especially from the place of production to the
place of demand without the necessity of low temperature storage. Whole milk
powder containing about 27% fat does not require low temperature storage provided it meets other requirements. If such a thing is made possible for cream and
butter fOf later use as butter or btltter spread, then it will be of great help
for this country where refrigerated' storage is not easily or inexpensively
available every where. Hence this work was undertaken to study the changes that
take place in the physico.chemicalprop~rties of h!Jtter powder from buffalo milk
during one year storage under di!fneilt conditions.
MATERIALS AND METHODS
Manufacture of bulter powder: Three batcheso'f butter powder from buffalo
milk containing 80 % fat, using ripened cream as the source of fat and skim milk
- • Dpta taken from first ;~ib'o~'s Ph.D. thesis, 1981, Kur~kshetra University.
IP~~sent address: Dept, of Agri. Engg., l.I-T., Kharagpur, W.B.,lndia
98
AsrAN JOURNAL OF I)AiRy RESEARCH
powder as the encapsulating mate,ial. a[ldC()Dtai~it!g.1% each of sodium citrate
and glycerol monostearate were manufactured as diJine/!,ted earlier (Prasad and
Gupta, 1982).
P.~kaglDg and storllge conditions:
The hll'tter powder 'vas packed in fruit
lacq~e4 tin CQntairters (undernittogen) or polyethylene bags (300 gauge) of one
kg capacity each, and stored at 5 ± 2°C '-or 3Q ,± 1°C. - Samples were drawn
at montl1ly intervals for the first 6 months and., thereafter. at 9 and 12 months.
Analytical methods: Butter powder was analysed for moisture and acidity
(lSI, 1975), fat (Milk Industry Foundation. 1,959). free (extractable) fat (Hall
~nd Hedrick, 1971), expressible (at 30 and 45<iC) fat (ShOW et al., 1967). free
fatty acids content (Thomas et al:, 1954). peroxide value (Smith. \939), tbiobarbituric acid (TBA) value (Sidwell iiI ai. , 1955), bulk density (Hall and Hedrick,
1971) and flowability (Neumann, 1963 and Sjollema, 1963}.
RESULTS AND D]SCU$SION
The keeping quality butter J>()wdcr is dependent on 'the cbemical changes
that would take place during storage; Further the 'typebfplIckaging and storage
conditions are bound ,to influence suell cbahges.Fbrestirrtating the optimum
packaging and storage conditions of the product, butter powder from buffalo milk
with 80 % fat was manufactured. packaged -and stored, and analysed for one year,
the results of which are being discussed here.
Moishlre content: The type of 'packaging material, storage temperature
and period of storage had statistically significant (p less thall 0.01) effect on the
moisture content (Table J ).Therc was no lo~sQr gain in moisture content of the
product stored in tins but the product stor.:d in PH 1;>a.gs absorbed considerable
amount of moisture during storage, thejntake being higher at 30°C, Considering
the smrage peliod. the moisture content in thc·product increased Significantly
(CD, 0.7925) after one month.
Lactose, being a major constituent Of 'n on-fafty ph!lse in butter powder,
.can be assumed to exist in the glass form as ill d rjed milk (Crossley, 1962). This
form of lactose has a tendency to absorb ·.moisture .from the surrounding air containing more than 50 % rdative humfdity(Supplee; 1926; TrOY and Sharp, 1930),
and crystallize out as alpha-lactose monohy-drate . ,
Change in oddity; The acidity of butter p6wderintreased (Table 1) progressively. Slatistical analysis showed that :storage 'Period, packaging matcrial and
storage temperature significantly ' (p less than 0.0 n affected the acidity of the
. proouct. After 3 months of storage theprodud had significantly increased
acidity (CD, 0.0017), and greater rise in ·acidity was observed in the product packed
in PE bags as compared to lin cans, the higher temperature accelerated this change.
The enhanced rate of acidity development in PE bags at 30°C might be due to increase in moisture content as also reported by Coulter et al. (1948) in whole
milk powder.
Vol., I. No.2. i982
Table 1.
Properly
Changes in the chemical propel'Ucs of butter powder from buffalo mill.:
,during storage
'
Storage
r-~- - - '-'
%
Acidity. %
lactic acid
2
3
PC
0.13
0.73
0.73
0.73
0.73
0.94
0.73
0:74
'i.03
0.72
0. 73
I.()<)
PR
0.73
0.97
1.18
TC
0.346
0.336
0 .346
0.346
0.346
0.347
0.345
0.349
0.247
IC
TR
TR
PC
PR
Free fatly acids, TC
% oleic acid TR
PC
PR
Perollide value. TC
meqlkg fat
TR
PC
PR
TBAvalue.
absorbance
TC
TR
PC
PR
Free fat. % oC
total fat
Storage period,. in monLhs
_ _ _ _ _ _ ..A.._._' _ _ - - _ _ _ _ _ -..
]
5
6
o.n
1.7J
0.73
0.73
1.18
1.99
0 .73
0 .73
1.56
1.99
0.73
0.71
1.47
0.72
0.72
l.l2
1.52
'0.346
0.341
0.348
0.'347
0.348
0.347
0.348
0.349
0.34$
0.3"8 .
0.347
0.350
0;349.
0.349
0.347
0.353.
0.348
0.349
0.347
0.352
0.349
0.3511
0.349
0.357
0.351
0.'356
0.354
0.364
Q.246
0.247
0.250
0.253
.0.243
0.252
0.243
0 ,258.
O.~45
0 ;:>47
0.250
0.24S
0.262
0.245
0.247
0.247
0.247
0.247
0.250
0.263
0.248
0.250
0.249
0 .265
0.250
0.252
0.254
0.274
0 :000
0 .000
0.000
0.000
0.000
0.000
0.000
0.000
O.bOO
0.000
0.000
0.573
0.853
0.748
2.017
0.879
0.000
0,000
0.000
0 ) 62
}.029
1.139
1.140
1.719
1.154
0.574
1.148
0.864
1.161
0 .703
0.704
1.290
2.136
0.021
p.02l
0.021
0 .021'
0.020
0.D25
0.022
0.1)16
0 .014
0.027
0.02!)
0.023
0.025
0.02(}
0.020
0.040
0.026.
0.040
0.022
0,043
0.026 0.030
0.046 0.048
0.047 . 0.050
OM! 0.065
0.038
0.052
0.062
0.083
0 .044
82.1.2 , B3·$P,
86.09
conditiouO'
Moisture.
99
0.24.1
0.~47
80.34
80.)4
80.79
81 .61
80 .92
81.61
81.15
82 :26
81.56
82.34
82.00
82.57
82.39
Expressible fat, TC
% of total fal TR
at JO"C
PC
30.89
20:89
20 .89
22 .51
24.40
2308
23.20
25.20
27:02
PR
2v.~9
2~.:48
. 2645
24.95
21 .05
27.70
2&-82
fa t TC
% of total fat TR
at 4S·C
PC
~7, 33
4t47
4445
43.04
41.92
42.51
49.86
44.69
48.83
TC
TR
80.34
PC
PR
Expr~sible
PR
80.~4
37.33
37.)3
37.33
83.]3
.52.33
55.11
5052
55.67
4
0.251
0.250
0.258
83.12
83.16
84. 19
25.97
2ti.t2
29.07
33.8J
18.10
.59.30
59.03
0,73
Ll4
U3~
1.146
1.B66
o ~47
12
UI
2.16
O. 0~1
0.074
0.113
84.48
84.01
84.93
g4.51
85.05
84.90
860<)
85.42
86.10
85.86
86.84
86.78
86.29
88.00
28 .24
30.31
32 93
37.34
29.05
32.51
33.73
39.44
32.06
33.l2
34.60
39.75
45 . 15
36.04
41 .88
48.12
60.72
64.11
61.29
64.31
64. ll
7058
6774
71.95
70.73
7483
72.38
77.65
nos
6098
- -- --_
__._
...
0.~48
9
- --
74.88
71.92
71.79
T-tin cans; P=PolyeLhylene bag s; C= ~=:2'C andR=30±LoC.
Change iii free fatty acids cn.nfent: 'The free fatty .acids (Ff A) content of
butter powder increased consi(!embly (Table I) in PE bags but not so much in tin
cans. The increa,e was significant (p less than 0.01) during storage which was
maximum for PE bags at 30°C (PR) followed by tins at 30·C (TR). PE bags
at jOc (PC) and tins at SoC (TC). However, there was no significant (CD, 0.0022)
difference between the FF A contents of butter powder slored in Te. TR and PC.
100
ASIAN JOURNAL OF DAIRY RESBARCH
After 4 months, the average FFA content was significantly (CD, 0.0034) higher than
the initial value, thereafter no significant change was observed upto 9 months. The
greater increase of FFA content inPR may be .attributed to the greater moisture
absorption which in turn -resulted iil greater fat breakdown.
Change In peroxide value (PV): The product had no PV to begin with and
for upto 3 months (Table 1). whereafter it increased progressively, particularly in PR
and PC, followed by TC and TR at 4 months. The type of package significantly
affected (p less than 0.0 I) the PV. The product in PV showed markedly higher PV.
Although the hill-her storage temperature caused faster and greater development of
peroxides, the rise in PV \\'as not. significantly different from that of the lower temperature storage. The average PY (0.562) rose 'significantly (CD, 0.254) at 4 months.
After attaining a maximum increase at S months under m05t storage conditions, the
PV tended to decline abruptly espeCially at 6 months followed by gradual rise or
drop. Thus the initial induction phase was followed by rapid peroxide build-up
and then decrease in peroxide concentration.
The PV being the measure of the extent of fat oxidation its initial rise
signifies more extensive oxidativechange&. However, after a certain stage the PV
tended to decline presumably because of g'reaterdecomposition of peroxides formed
as a result of autoxidation than the formation of new peroxides because of the
reduced oxygen ~vailability during ~torage (Pyenson and Tracy, 1946; and Crossley,
1962).
Change in TBA value: Like peroxide value, TBA values were also lower
in the powder stored in tin cans than in PE bags. Higher storage temperature
(30°C) persumably oxidized the fat rapidly and to a higher degree resulting 'in
higher TBA value. On the whole maximum product deterioration took place in
PE bags at 30·C and least In tin cans at 5.°C. There was no appreciable difference
in lin cans at 30°C and PE bags at SoC.
Chonge in free (extractabie) fat, content: It is known that when a pOwdered product containing appreciable amount of fat such as whole milk powder
and cream is stored, its free fat content increases during starage, and the release of
free fat depends on the type of packaging, temperature and period of storage.
(Lampitt and Bushill. 1965;, Faystova, 1960; TranThe Truyen, 1915; Sharma, 1978).
The results obtained in this study (Table ' 1) seem to agree well with these observations. The free fat content showed agraduai ipcrease during storage, the increase
being significant (CD, 1,034) after second month, The greater rise in the free fat
content of butter powder in tins at 30"C ,tlian in PE bags at SoC indicated that it
was more a function of temperature rather than of the moisture content which
increased much more in PE packed product even at S·C.
Change in exp~essibte fat content: A gradual increase in the expressible
fat content wil'h the peTiod of storage was observed (Table 1). The temperature
Vol. I. No.2, 1982
101
and period of storage significantly (p loss than 0,0 I) affected tbe quantity of expressible fat released at both 30 and 45°C, whereas packaging material was significant
(P less than 0.01) only at 30°C. In general tin cans p rovided better protection to
the product than PE bags, and the loWer storage temperature (SoC) helped in
keeping the powder stable for longer period. Tripp l!f at. (l966a;1966b) also
found that decrease in storage temperature to 2-4°C from 24-26°C resulted in
35 to 40% decrease 'in ihe quantity of expressible fat.
Cbange in bulk dellsity: The loose bu lk density of tbe butter powder increased significantly (p less tban 0.01) with the period of storage (Table 2), the
change being significant (CD, 0.006) after olle month. However, bulk density
remained nearly constant thereafter upto 4 months before increasing again during
subsequent storage. Apparently tbere was no appreciable difference in the loose
bulk density of the butter PQwder stored under differel].t conditions, except PC
being significantly (CD, 0.004) different ftom TC il,fid PRo
Table Z.
Changes in the physical properties of butte( powder from buffalo milk,
du"rlngstorage'
Storage period, in months
Property
Storaa:e
condition
TC
Loose bulk
density. glee TR
PC
PR
Packed bulk
density. glee
TC
TR
PC
PR
Flowability,
angle of
repose in
degrees
TC
TR
PC
PR
PCS
PRS
,-- _ _ _ _ _ _ _ _ _ _ _ _ ..A.. _ _ _ _ _ _ _
0
1
2
0.26\
0.261
'0 261
0261
0.260
0.268
0 .269
0 ,269
0 .268.
0.274
0.268
0.271
0.269
0.269
0.274
0 .'2.67
Q.270
0.213
0.265
0.4 61
0.460
0.462
0.460
0468
0.453
().460
0...162
0,465
51.06
51.83
50.19
52.80
48.68
50.41
0.472
0.472
0.472
0.472
48.59
48.59
48 .59
48 .59
47.21
47.21
O.4~
(lA63'
0 .465
49.46
49 ,60
49.5:?
50.29
48.17
47.79
50.33
50,97
49.74
SI.6'J
48.SZ
4.8.77
3
4
0 . 2~
5
6
0.276
0.284
'0.277
0 :273
0.293
0.294
0286
0.267
.0,459
0448
0.458
0.456
0.458
0.443
0.447
0.454
0 .445
0.447
0.447
50.32
51.86
51.63
53.04
49.03
50.22
51.30
52.30
52.47
53.23
.50.60
50.31
51.70
52.71
52.8'>
53.75
50.67
50.50
O~45B
_ _ _ _ _ -..
9
12
0.291
0.279
0.300
0.268
0 .269
0266
0291
0 .28S
0.449
0.447
0.441
0.463
0 .467
0.4.58
0.461
52.40
53.11
53.33
54.98
50.88
53.63
52.90
53.94
S3 .95
55.79
51.90
54.41
0431
T-tin eans: P=Polyethylene bags; C=5±2' C; R=30:.l;1 °C and .S=with 0.5 % sodium
aluminium silicate.
The packed bulk density, unlike loose bulk density, decreased significantly
(Table 2) with the period of ~torage , the decrease being significant (CD, 0.009)
after 2 months, Temperature of storage and type .o f packaging material did not
seem to affect the packed bulk density.
Change In lIowability: The :f\owability oral1 butter powder samples seemed
10 decrease during storage as Shown by the increase in angle of repose (Table 2).
Analysis of variance indicated tnat packaging material, presence (of sodium alumi.
102
nium silicate, 0.5% dry mixed in the powder \:lefore packaging) or absence of free
flowing agent, temperature and period of storage significantly (p less than 0.01)
affected flow ability. The flowabitity decreased greatly after 6 months of storage in
powder packed in PE bags with or without sodium aluminium silicate at 30°C. The
btrtter powder in PR became lumpy unlike the other samples which did not show
lumpiness even after 12 months. Higher storage temperature (30°C) resulted in a
greater decrease in the flowability in comparison to that of lower temporature
stored product. Addition of sodium alumini'um silic:l,te decidedly decreased the loss
in flow ability during storage particularly in the tin-packed product which was not
the case in the PE·b.lgged proJuct probably because of relatively higher moisture
gained in the latter.
Because of the decrease in osmotic press·ore and increase in vapour tension,
some of the moisture absorbed is given up resulting In 'cakil1g' of the powder
(Sharp. 1938). Lea and White (1948) reported that lactose crystallized in spray
dried skim milk powder after only one day at 37°C with 7.6% moisture, while this
resulted after 10 days at 28.SoC and after 100 days at 20°C. Choi et aI. (1951)
established a moisture content of 7.5 to 8.0% in skim milk powder, and 6.5 to
1.0% in whole milk powder ~s the critical limits above wh.ich a rapid and extensive
crystallization of lactose took place. However, this 'critical" moisture content in
butter powder 'Was observed to be as 19w as 1.7% aboy/;:: which caking took place in
product packed in PE bags at 30"C after '6 months.
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