Effect of germination on the biological value, digestibility coefficient and net protein utilization of some legume proteins


Venkataraman, L.V.; Jaya, T.V.; Krishnamurthy, K.S.

Nutrition Reports International 13(2): 197-205

1976


The digestibility coefficient and biological value of the proteins of greengram, cowpea and chickpea (ungerminated and germinated for 24 and 72 hrs) were determined at 10% protein level using albino rats. Among the three legumes, greengram showed the lowest biological value in the ungerminated raw form. Cooking significantly reduced the biological value in cowpea and chickpea in the ungerminated state. Germination did not show any improve ment in biological value in the three legumes studied. The digestibility decreased in the 72 hrs. germinated cowpea and chickpea while greengram showed an increase on germination. The net protein utilization values were higher for cowpea as compared to the other two legumes.

NUTRITION
REPORTS
INTERNATIONAL
EFFECT
OF
GERMINATION
ON
THE
BIOLOGICAL
VALUE,
DIGESTIBILITY
COEFFICIENT
AND
NET
PROTEIN
UTILIZATION
OF
SOME
LEGUME
PROTEINS
L.V.Venkataraman,
T.
V.
Jaya
and
K.S.Krishnamurthy
Protein
Technology
Discipline
Central
Food
Technological
Research
Institute,
My
so
re,
India.
ABSTRACT
The
digestibility
coefficient
and
biological
value
of
the
proteins
of
greengram,
cowpea
and
chickpea
(ungerminated
and
germinated
for
24
and
72
hrs)
were
determined
at
10%
protein
level
using
albino
rats.
Among
the
three
legumes,
greengram
showed
the
lowest
biological
value
in
the
ungerminated
raw
form.
Cooking
significantly
reduced
the
biological
value
in
cowpea
and
chickpea
in
the
ungerminated
state.
Germination
did
not
show
any
improve
ment
in
biological
value
in
the
three
legumes
studied.
The
digestibility
decreased
in
the
72
hrs.
germinated
cowpea
and
chickpea
while
greengram
showed
an
increase
on
germination.
The
net
protein
utilization
values
were
higher
for
cowpea
as
compared
to
the
other
two
legumes.
INTRODUCTION
Legumes
are
important
sources
of
proteins
in
Indian
diets.
They
differ
to
an
appreciable
extent
in
protein
content
and
amino
acid
profile
(1).
The
nutritive
value
of
legume
proteins
has
been
extensively
investigated(1-6).
However
similar
information
on
the
germinated
legumes,
which
form
a
good
part
of
Indian
diets
is
limited.
During
germination,
the
proteins
are
hydrolysed
with
increased
proteolytic
activity
(7,8).
Whether
such
changes
affect
the
biological
value
and
protein
utilization
is
not
well
established.
Everson
et
al.
(9)
reported
improvement
in
biological
value
of
soybean
on
germination,
while
Chattopadhyay
and
Banerjee
(10)
observed
a
decrease
in
biological
value
in
some
germinated
legumes.
FEBRUARY
1976
VOL.
13
NO.
2
197
NUTRITION
REPORTS
INTERNATIONAL
In
our
earlier
paper
(11),
the
results
of
studies
on
the
effect
of
cooking
and
germination
on
the
protein
efficiency
ratio
of
greengram,
cowpea
and
chickpea
were
reported.
In
the
present
paper
the
results
of
studies
on
the
effect
of
germination
on
the
biological
value,
(BV),
digestibility
coefficient
(DC)
and
Net
Protein
Utilization
(NPU)
of
three
common
legumes,
greengram
Phaaeolus
aureus),
cowpea
(Vigna
sinensis)
and
chickpea
(
Cicer
arietinn
un
are
reported.
EXPERIMENTAL
Preparation
of
levee
samples
and
diets:
Greengram,
cowpea
and
chickpea
were
obtained
locally.
Details
of
germination
and
cooking
conditions
are
reported
in
our
earlier
paper
(11).
The
diets
contained
10%
protein
and
nitrogen
content
of
all
the
diets
were
estimated
by
Kjeldahl
method.
The
composition
of
the
diets
is
shown
in
Table
1.
Greengram
diets
were
evaluated
in
experiment
I,
cowpea
and
chickpea
in
experiments
II
and
III
respectively.
In
each
experiment,
there
were
four
diets,
viz.
ungerminated
(UG)
uncooked
(UC):cooked,
24
bra
germinated
(G)
cooked
and
72
hrs(G)
cooked.
Animal
experiment:
Wistar
strain
male
rats
weighing
between
120-140
g
were
grouped
by
randomized
block
design.
The
rats
were
housed
in
individual
metabolic
cages.
The
method
of
Mitchell
and
Carman
(12)
was
adopted
for
N-balance
studies.
In
order
to
give
correc-
tion
for
endogenous
nitrogen
loss,
the
rats
were
kept
on
corn
starch
diet
for
10
days.
After
allowing
adjustment
for
the
first
5
days,
collection
of
urine
and
feces
were
made
for
a
subsequent
period
of
5
days.
Following
this
the
rats
were
fed
experimental
diets.
Urine,
feces
and
the
residual
food
were
collected
for
5
days,
after
the
initial
5
days
adjustment
period.
The
biological
value
and
digestibility
coefficient
were
calculated
by
the
method
of
Chick
et
al.
(13).
Net
protein
utilization
(NPU)
was
expressed
as
a
product
of
biological
value
and
digestibility
coefficient
and
divided
by
100.
The
results
were
statistically
analysed
by
Duncan's
Multiple
Range
test
(14).
RESULTS
Greengram
diets:
The
biological
value
(BV),
digestibility
coefficient
(DC)
and
net
protein
utilization
(NPU)
of
greengram
diets
are
presented
in
Table
II.
The
BV
of
ungerminated
raw
greengram
was
61.4%
and
no
significant
198
FEBRUARY
1976
VOL.
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NO.
2
9L61
A
11V1
11
1111,
4
O
w
O
Table
I
Composition
of
the
experimental
diets
(g/kg
diet)
(Duration
of
experiment
20
days
(10%
protein
level.)
Experi-
ment
No.
Diet
Vitamin
1
Salt
Legume
premix
m
i
x
2
Corn
Fat
starch
I
3
greengram
series
435
10
20
100
435
11
4
cowpea
series
380
10
20
100
490
III
5
chickpea
series
585
10
20
100
285
Vitamin
premix:
According
to
Chapman,
D.G.,
Castillo,
R.
and
Campbell,J.A.
.Can.J.Hiochem.Physiol.
2i,
678
(1959).
Salt
mix:
recording
to
HUbbel,
Mendel
and
Wakeman,
J.Nutr.
14,
273
(1937).
Greengram
series:
Total
of
4
diets
containing
ungerminated
raw,
ungerminated
cooked,
24
hrs.
germinated
cooked
and
72
hrs
germinated
cooked.
Cowpea
series;
Total
of
4
diets
with
details
as
in
3.
5
Chickpea
series:
Total
of
4
diets
with
details
as
in
3.
1
2
3
4
NU
T
RI
T
ION
REPO
RT
S
INTE
RNAT
IONA
L
NUTRITION
REPORTS
INTERNATIONAL
change
was
observed
on
cooking.
The
germinated
cooked
diet
also
showed
BV
comparable
with
the
raw
ungerminated
ones.
In
the
ungerminated
form
digestibility
coefficient
decreased
on
cooking.
Significant
increase
in
digesti-
bility
was
observed
at
72
hrs
germinated
greengram
diet.
Table
I/
Biological
value,
digestibility
coefficient
and
net
protein
utilization
of
greengram
proteins
(Duration
of
expt.
20
days-Mean
values
for
5
male
rats/group
at,10%
level
of
protein)
Si.
No.
Diets
Biolo-
diges-
Net
protein
gical
tibility
utilization
value
coeffi-
cient
A.
Ungerminated
uncooked
greengram
61.4
72.4
44.5
B.
Ungerminated
cooked
greengram
62.0
68.4
42.4
C.
24
hrs.
germinated
cooked
greengram
59.0
72.2
42.6
D.
72
hrs
germinated
cooked
greengram
63.0
81.2
51.2
Results
of
test
of
significance
(Duncan's
multiple
range
test)
Diets
C
A
B
D
SE
P(3,12
d.f)
BV
59.0
61,4
62.0
63.0
e
2.12
3.79
N.S.
Diets
B
C
A
D
DC
68.4
72.2
72.4
81.2
+
0.84
41.76**
Note:
**
P
0.01,
N.S.
not
significant.
Any
two
mean
scores
not
underlined
by
same
straightline
differ
significantly.
NPU
increased
from
44.5%
in
the
ungerminated
raw
diet
to
51.2%
in
72
hrs
germinated
greengram.
Nitrogen
balance
data
are
shown
in
TableIV.
The
percent
nitrogen
retained
was
28.5%
in
ungerminated
raw
diet
which
decreased
to
22.5%
at
72
hrs
germination.
Cownea
diets:
The
results
of
biological
evaluation
are
given
in
Table
III.
The
BV
for
UG
raw
cowpea
was
79.2%
200
FEBRUARY
1976
VOL.
13
NO.
2
NUTRITION
REPORTS
INTERNATIONAL
on
cooking.
BV
was
significantly
reduced
to
68.0%
in
72
hrs
germinated
cooked
cowpea
diets.
The
TD
was
compa-
rable
in
the
UG
raw
and
cooked
diets
and
significantly
decreased
with
germination
with
72
hrs.
No
significant
difference
was
found
in
the
NPU
of
UG
raw
and
cooked
cowpea.
However
the
NPU
values
decreased
with
increased
periods
of
germination.
The
percent
nitrogen
retained
was
48.4
in
ungerminated
raw
diets
(TableIV).
Nitrogen
retained
decreased
to
37.8%
at
72
hr.
germination.
Table
III
Biological
value,
digestibility
coefficient
and
net
protein
utilization
of
cowpea
proteins
(Other
details
as
in
Table
II)
81.
No.
Diets
Biolo-
gical
value
96
Dige-
stibi-
lity
coeffi-
cient.
96
Net
protein
utilization
4
E
Ungerminated
un-
cooked
79.2
92.0
72.9
F
Ungerminated
cooked
cowpea
74.6
93.4
69.7
G
24
hrs
germinated
cooked
cowpea
74.4
89.2
66.4
H
72
hrs
germinated
cooked
cowpea
68.0
85.6
58.2
Diets
H
G
F
E
SE
F(3,12
d.f)
BV
68.0
74.4
74.6
79.2
+
1.08
17.93**
Diets
DC
85.6
89.2
92.0
93.4
+
1.21
8.13**
Chickpea
diets:
BV
was
significantly
lowered
on
cooking
in
ungerminated
chickpea
diets
with
the
value
of
80.4
and
69.4%
respectively
for
raw
and
cooked
ones
(Table
V).
The
germinated
cooked
chickpea
diets
gave
higher
BV
than
the
ungerminated
cooked
diets.
The
DC
was
lower
in
the
UG
cooked
(68.2%)
compared
to
the
raw
ones
(78.0%).
The
germinated
cooked
chickpea
diets
showed
better
digestibi-
lity
than
the
corresponding
value
for
ungerminated
cooked
chickpea
diet.
The
NPU
values
in
ungerminated
and
germi-
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61
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0
A
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UTRITI
ON
REPORT
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INTE
RNA
T
IONA
L
Table
IV
Nitrogen
balance
data
for
rats
fed
on
germinated
legume
proteins
(Mg/day/rat)
(other
details
as
in
Table
II)
Legume
Duration
of
ger-
mination
(hrs)
Uncooked
(UC)/
Nitro-
intake
gen
Nitrogen
excreted
Urinary
Fecal
Total
nitrogen
nitrogen
nitrogen
Reten-
tion
Percent
nitro-
gen
retai-
ned
Cooked
(C)
Green
gram
o
uc
149
52
55
107
42
28.5
n
0
C
172
58
73
131
41
23.3
n
24
C
184
72
72
144
4o
21.6
.1
72
C
124
49
47
96
38
22.5
Cowpea
0
UC
140
39
34
73
67
48.4
"
o
C
169
51
37
88
81
48.0
"
24
D
161
50
36
86
75
50.9
it
72
C
160
53
37
9
0
70
37.8
Chickpea
o
UC
214
7o
66
136
78
41.2
is
o
C
223
7o
92
162
61
23.o
"
24
C
234
68
82
151
83
35.5
"
72
C
234
67
82
148
86
36.0
Average
endogenous
urinary
nitrogen
=16mg;
Average
endogenous
faecal
nitrogen=20
mg.
NUTRITION
REPORTS
INTERNATIONAL
nated
samples
ranged
from
47.3
to
58.8%.
There
was
signi-
ficant
reduction
in
NPU
in
the
ungerminated
cooked
chickpea
diet.
Compared
to
the
corresponding
ray
diet,
no
difference
was
found
in
the
germinated
cooked
diets.
The
percent
nitrogen
retained
was
significantly
reduced
on
cooking
in
the
UG
chickpea
diet.
Table
V
Biological
value,
digestibility
coefficient
aid
net
protein
utilization
of
chickpea
proteins
(Other
details
as
in
Table
II)
Si.
No.
Diet
Biolo-
gical
value
Digesti-
bility
Coeffi-
cient
Net
pro-
tein
uti-
lization
9
6
I
Ungerminated
un-
cooked
chickpea
J
Ungerminated
cooked
chickpea
24
hrs.
germinated
cooked
chickpea
L
72
hrs.
germinated
cooked
chickpea
80.4
69.4
75.4
72.2
78.0
58.8
68.2
47.3
73.8
58.8
73.6
53.1
Diets
J
L
R
I
SE
F(3,
12
d.f)
BV
69.4
72.2
75.4
80.4
+1.83
6.'**
Diets
J
DC
68.4
73.6
73.8
78.0
+0.97
17.13**
DISCUSSION
Die
nutritive
value
of
a
dietary
protein
is
dependent
on
its
essential
amino
acid
composition.
Other
factors
affecting
the
nutritive
value
are
(i)
the
relative
proportions
of
different
amino
acids
present
in
them
r
ii
)
the
presence
of
indigestible
carbohydrates
and
i)
the
presence
of
trypsin
and
growth
inhibitors.
Germination
may
also
affect
the
nutritive
value
of
the
proteins
due
to
better
availability
of
some
essential
amino
acids
(9).
In
the
present
study,
no
improvement
FEBRUARY
1976
VOL.
13
NO.
2
203
NUTRITION
REPORTS
INTERNATIONAL
was
observed
in
the
biological
value,
digestibility
coefficient
and
net
protein
utilization
as
a
result
of
germination.
Chattopadhya
and
Banerjee
(10)
however,
reported
increase
in
RV
in
chickpea,
blackgram
and
lentil
proteins
and
decrease
in
BV
in
greengram
and
pea
proteins.
Everson
et
al.
(9)
also
found
improvement
in
the
BV
in
soybean
as
a
result
of
germination.
Cooking
of
the
ungerminated
greengram
did
not
decrease
BV
while
in
the
case
of
cowpea
and
chickpea
proteins
there
were
significant
reduction
in
BV
due
to
cooking.
Further
studies
aro
required
to
elucidate
the
cause
for
the
above
findings.
ACKNOWLEDGEMENTS
The
authors
thank
Mr.S.Dhanaraj
for
statistical
analysis
of
the
data
and
Dr.
M.Swaminathan,
Emeritus
Scientist,
Central
Food
Technological
Research
Institute,
Mysore,
India
for
critically
reviewing
the
manuscript.
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of
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az,
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of
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FEBRUARY
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