372
Journal homepage: www.fia.usv.ro/fiajournal
Journal of Faculty of Food Engineering,
Ştefan cel Mare University of Suceava, Romania
Volume XVII, Issue 4 -2018 , pag. 372 - 384
CHARACTERIZATION OF THE EFFECT OF MODULATED DRY HEAT
PROCESSING CONDITIONS ON ESSENTIAL AND NON ESSENTIAL AMINO
ACID PROFILE OF UNSEASONED BREADFRUIT (V. DECNE) SNACK SEEDS
*Azubuike C UMEZURUIKE
1
, Joel NDIFE
2
, Chinwe NWACHUKWU
3
1Scientific Directorate, Ministry of Science and Technology/Absiec, Abia State Government Service, Umuahia,
Nigeria, realmira4ac@gmail.com
2 Department of Food Science and Technology, College of Applied Food
Sciences and Tourism, Michael Okpara University of Agriculture, Umudike Nigeria.
3 Department of Food Science and Technology, Imo State University, Owerri
*Corresponding author
Received 16th August 2018, accepted 27th December 2018
Abstract:
The objective of this study was to determine the functional relationship between Roasting temperature
(RT), Roasting time (RM) and Feed quantity (FQ) and the yield of all essential and non-essential
amino-acids obtainable through modulated roasting of breadfruit seeds harvested from
undomesticated breadfruit tree. Roasted seeds of breadfruit (V. Decne) consumed as snacks represent
an important source of protein/amino acids needed for good health in humans. However, these amino
acids are needed in certain levels in order to achieve their metabolic usefulness. Processing methods
influence their useful concentrations. Central Composite Design at 3 process variables (RT, RM, FQ)
and 5 levels (-1.682, -1, 0, 1, 1.682) was used for the experimental runs. Amino acid assay was
conducted and the results obtained from experimentation were statistically analyzed. Similar amino-
acids but in different contents were present both in raw and roasted seeds. Roasting temperature, time
and feed quantity were significant (p < 0.05) terms in the models which influenced the quantum of
amino acid, either in linear, squared or interactive terms. Cysteine and methionine showed some heat
stability. Other non-essential amino acids were observed at concentration range of 0.29 g to about 7.0
g. Tryptophan was not detected at temperatures higher than a hundred and forty degrees Celsius. The
predicted optimum total of amino acids of roasted seed samples was 66.02 % of the total amino acids
of the control. The predicted values for optimum process condition were in good agreement with
experimental data. Hence, roasting of breadfruit seeds for snacking at the identified optimum variable
combination will supply safe and recommended daily levels of amino acids in humans.
Keywords: breadfruit seeds, roasting, essential, non -essential amino-acids.
1. Introduction
In Nigeria, breadfruit ( v.Decne) seeds are
consumed in roasted forms as snacks. The
roasted snack seeds are popular convenient
snacks among travellers and commuters or
when packaged in bottles shared as social
gifts. Roasted breadfruit (V. decne) seeds
is an important source of protein/amino
acids for consumers. The reported amino
acids of breadfruit and other legume seeds
include alanine, arginine, aspartic acid,
glutamic acid, cysteine, glycine, histidine,
isoleucine, leucine, lysine, methionine
phenylalanine, proline, serine, threonine,
tyrosine,tryptophan and valine [1,2].
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mailto:Realmira4ac@gmail.com
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
373
Histidine, isoleucine, leucine, lysine,
methionine, phenylalanine, threonine and
valine are essential amino acids that must
be provided in the human diets for
metabolic development, immune boosting,
neurotransmission, fertility, inhibition of
reactive oxygen species, anti-inflammation
etc. [3.4.5.6.7]. Only methionine, cysteine
and tryptophan are limited in most legumes
including breadfruit seeds [8]
Other studies that explored the extraction
and composition of breadfruit seeds [8,9]
reported important health nourishing
nutrients of breadfruit seeds. The protein
content of breadfruit (v. Decne) is
comparable to other legumes [10].
Breadfruit seeds maybe seasoned with salt
or spices before roasting. Usually the seeds
are roasted without being hulled. After
roasting the breadfruit seeds are consumed
as snacks. Traditional roasting of legume
seeds and nuts for snacking takes about 30-
40 min at very high temperatures with
obvious deleterious effect on the nutrients
[11]
The outcome of processing treatments are
influenced by the processing parameters of
temperature, time, heat transfer rates,
moisture content, seed chemistry, seed
physics, processors skill etc. [12,13].
Previous studies focused more on
parboiled seeds with little attention on
roasted seeds. Studied of Iwe and Ngoddy
[12] and Nwabueze [13] successfully
optimized the process conditions nutritive
properties of parboiled breadfruit
(v.Decne) seeds but no such magnitude of
research efforts on dry heat processing are
recorded for roasted seeds. This suggests
that consumers of roasted seeds may be
accessing low nutrients.
As the global food trend tilts towards
convenience food, emphasis is put now on
roasted high energy density convenient
snacks such as roasted breadfruit seeds,
groundnuts, almonds etc. More studies are
needed to determine optimum process
variable combination for enhanced yield of
amino-acids and other health promoting
factors of roasted breadfruit seeds
consumed as snacks.
Heat treatment improves protein
digestibility, amino acid availability in
diets [14,15, 16], reduces the amino acids
content of our diet to levels that are non-
toxic in humans [17,18]. As most safe
levels of amino acids fall within 5g-10g/
day [19], it is important to determine the
processing points of convergence as
processing variable optima between safety
and critical needs of amino acids from
roasted breadfruit (v. Decne) seeds
consumed as snacks. For instance,
essential amino acids such as methionine,
histidine and cysteine which are very toxic
to human in higher concentrations and they
could be modified to tolerable and useful
levels by roasting. Roasting though leads
to denaturation and decomposition of
amino acids, still it remains an
indispensable food processing operation
for the production of roasted breadfruit
snack seeds.
This study was designed as an evolving
study carried out to determine and
characterize the process variable
combinations for optimum dry heat
processing spectrum and yield of essential
and non-essential amino acids in the
roasting of breadfruit seeds by using
overall desirability approach.
Desirability function approach is used to
transform multi- responses problem into a
single response objective function (overall
Desirability) by means of mathematical
transformation. Overall desirability
approach has been successfully applied in
many optimization studies [20]. It involves
the optimization of the desired product
quality within conflicting operational
process variables in the processing region.
([21]. The results of this study are
envisaged as a guide to breadfruit seed
processors for the production of safe and
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
374
nutritionally adequate levels of amino
acids in roasted breadfruit snack seeds.
2. Materials and methods
Collection of materials
Freshly pulped seeds of breadfruit (V.
Decne) were provided from
undomesticated breadfruit tree growing in
Umudike, Nigeria. The seeds were
screened for stones, sands, debris etc,
washed with portable water and dried
under shade at 28±40C for 34 hours. Seeds
were not seasoned with salt or spices for
flavour.
Experimental Design
The central composite Rotable Design was
used for the study. Three (3) variables 5
levels experimental layout at 8 factorial, 6
axial and 6 replications at the centre (Table
1) were employed. Effects of roasting
temperature, roasting time and feed
quantity on amino acids content of roasted
seeds were examined. Definition of
operational variables were carried out by
using Minitab statistical software version
15.
The input variable values were chosen
based on the information in literature and
reasonable enough to accommodate
statistically valid deductions [22]. The
range and values at star, axial and center
points were calculated using the equation
(1) as outlined in Table 2
x1= xi – x10
(1)
Where x1= Independent variable code
value
xi= Independent variable actual
value
xio= Independent variable actual
value of centre point
= Step change value
Experimental Roasting of samples
The unseasoned seeds ( samples) were
roasted in electric oven (Fishers Scientific
Co. UK) according to the experimental
layout. The roasted seeds are cooled,
hulled using a locally fabricated huller.
The roasted hulled seeds are edible snacks.
For amino acid assays, the hulled seeds
were milled and sieved into flour using a
200mm mesh. The flour samples were
placed in sterilized plastic bowls,
appropriately labeled and stored at ambient
28 ± 20C) temperature before use.
Table 1
Central Composite Rotable Design
Code Variables Combination Replications Experiments
X1 X2 X3
±1 ±1 ±1 8 1 8
±1.682 0 0 2 1 2
0 ±1.682 0 2 1 2
0 0 ±1.682 2 1 2
0 0 0 1 6 6
Table 2
Range and Levels of Experimental Runs
Codes -1.682 -1 0 1 1.682
Roasting Temperature RT (0C) X1 123.36 140 160 180 193.64
Roasting Time RM (min) X2 31.59 35 40 45 48.4
Feed Quantity FQ (g) X3 331.80 400 500 600 668.2
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
375
Determination of amino- acid profile:
The amino-acids profile of raw and roasted
breadfruit flour were determined using the
method described by [23, 24]. The samples
were dried to constant weights in oven,
defatted, hydrolyzed, and then evaporated
using rotary evaporator. Thirty milligrams
of each sample were mixed with 7ml of
HCl in a glass ampoule. Oxygen was
expelled from the mixture by passing
nitrogen into the ampoule. The glass
ampoule was heat sealed using a Bunsen
burner flame and placed in an oven
(1050C) for 22 hours. After heating, the
glass ampoules were let to cool, the tip was
opened and the content was filtered. The
filtrate was evaporated to dryness using
rotary evaporator at 400C.
The residue was dissolved in 5ml acetate
buffer (pH. 2.0) and stored in refrigerator
using plastic bottle. 5-10 microliters of
each sample were placed in amino-acid
cartridge and loaded into amino- acid
analyzer. The TSM analyzer separated and
analyzed the amino-acids in samples. The
data generated from the Technicon
Sequential Multi-sample analyzer were
quantitatively determined against the
standard Technicon auto analyzer (No 011-
648-0) chart.
Statistical analysis of results
Data of the study were analyzed and
presented as tables. For statistical
evaluation, data of study were analyzed
using Minitab statistical software (version
15 of Minitab Inc.Pen. USA) which
described the optimized global setting for
input variables and predicted optimum
yield of amino acids at 0.0 - 1.0
desirability bar. The effect of roasting
condition on amino acids of breadfruits
was described in regression terms by
+ (2)
Where Y= response, β0 = intercept, xiji=
Independent variables, e=error
Maximization of the fitted models was
performed using unified goals with defined
(0.1-1.0) limits. Adequacy of models was
defined by co-efficient of determination R2
and adjusted R2. The significant (p<0.05)
variables were identified and their effects
described in Linear, squared or cross
product terms. The coefficients of
determination were complemented with
their adjusted values and Standard error of
estimate S in judging the adequacy of
fitted models.
3. Results and Discussion
Adequacy of regression models of amino
acids
The co-efficient of determination R,
adjusted R2 and standard error of estimate
s were adequate to predict the variability in
amino acid content of the processed
breadfruit snack seeds. The co-efficient of
determination of R2 ranged from70% to
95% and all adjusted R2 values were above
65%. All S values indicated that data
points were 0.23 to 1.16% of the fitted line
and less than 7% which statistically
satisfied the prediction intervals.
Significance (p=0.5) of input process
variables X are described in linear, squared
and interaction terms.
The amino acid profile of the processed
breadfruit seeds flour is shown in Table 3.
All amino acids in the control were
contained in the processed flour samples in
varying proportions. The amino acids
identified were: histidine, isoleucine,
leucine, lysine, methionine, phenylalanine,
cysteine, threonine, aspartic acid, glutamic
acid, glycine, proline, serine, threonine,
tyrosine, tryptophan, arginine and valine.
The values of all the amino acids analyzed
progressively reduced as the roasting
temperature, roasting duration and mass
were extended simultaneously from 1400C,
1600C and 1800C to 31.59 min, 53 min, 40
min , 45 min, 48 min and 331.80g. 400g,
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
376
500g, 600g 668.20g for roasting
temperature, roasting time and feed
quantity, respectively.
Table 3
Amino acid profile of processed samples (g/16 gN)
Essential amino acids
S/N Experimental Runs H Is Iu Ly Me Ph Th Tp Va
1 1400C/35m/400g 2.23 2.90 5.70 4.18 0.73 3.99 2.70 Trace 3.18
2 1400C/35m/600g 2.25 3.01 6.00 4.27 0.75 4.05 2.73 Trace 3.25
3 1400C/45m/400g 2.00 2.89 5.10 3.11 0.70 3.80 2.57 ND 3.04
4 1400C/45m/600g 2.03 2.77 5.15 4.00 0.71 3.89 2.57 ND 3.10
5 1800C/35m/400g 1.80 1.70 4.03 3.30 0.60 3.20 2.21 Trace 3.05
6 1800C/35m/600g 1.82 1.77 4.33 3.21 0.61 3.50 2.33 ND 3.90
7 1800C/45m/400g 1.10 2.30 3.46 2.88 0.55 3.86 2.10 ND 2.96
8 1800C/45m/500g 1.50 2.38 3.59 2.91 0.57 3.39 2.01 ND 2.95
9 1260C/40m/500g 2.29 3.11 4.16 3.87 0.81 3.90 1.81 Trace 2.90
10 193640C/40m/500g 1.00 1.30 2.79 2.16 0.43 2.64 1.14 ND 2.03
11 1600C/31.59m/500g 2.30 3.11 7.53 3.64 0.69 3.47 2.71 ND 2.97
12 1600C/48.41m/500g 1.19 2.05 3.60 2.51 0.61 3.10 2.55 ND 2.90
13 1600C/40m/331.80g 2.13 2.11 3.37 3.00 0.59 3.05 1.95 ND 2.47
14 1600C/40m/668.20g 2.16 2.49 3.66 3.81 0.65 3.59 2.69 ND 2.95
15 1600C/40m/500g 2.20 2.28 3.49 3.49 0.63 3.35 2.31 ND 2.59
Control 3.16 3.60 6.8 7.10 1.53 6.10 3.22 0.4 4.5
Non-Essential
S/N Experimental Runs Al Ar As Cy Gl Gy Pr Sr Ty
1 1400C/35m/400g 2.66 5.58 6.00 1.50 8.10 3.97 2.00 3.63 2.35
2 1400C/35m/600g 3.01 5.62 6.10 0.95 8.20 4.05 2.53 3.30 2.41
3 1400C/45m/400g 2.35 5.15 5.58 0.90 7.71 3.93 2.30 3.56 2.25
4 1400C/45m/600g 2.33 5.10 5.91 0.95 7.60 4.00 2.41 2.30 2.17
5 1800C/35m/400g 2.07 4.60 5.40 0.90 6.70 3.41 2.37 2.41 2.07
6 1800C/35m/600g 2.17 4.71 5.70 0.91 6.48 3.53 2.39 2.37 1.99
7 1800C/45m/400g 1.85 4.14 5.30 0.80 6.00 2.91 2.30 2.30 2.10
8 1800C/45m/500g 1.88 4.25 5.35 0.88 6.16 2.94 2.29 2.28 1.71
9 1260C/40m/500g 2.05 4.77 5.99 0.90 7.60 3.99 3.01 3.01 2.51
10 193640C/40m/500g 1.80 3.25 3.01 0.45 5.13 2.21 1.21 1.20 1.07
11 1600C/31.59m/500g 2.04 4.90 5.90 0.80 7.61 3.19 2.60 2.60 2.41
12 1600C/48.41m/500g 1.19 3.90 3.89 0.65 5.88 3.00 2.67 2.66 2.07
13 1600C/40m/331.80g 1.85 3.17 3.96 0.71 6.40 3.01 2.21 2.23 1.97
14 1600C/40m/668.20g 1.90 3.53 4.01 0.75 6.72 3.10 2.33 2.33 2.13
15 1600C/40m/500g 2.01 3.28 3.99 0.73 6.88 3.20 2.27 2.27 2.01
Control 4.5 9.86 11.01 2.00 19.50 5.15 4.00 5.10 3.5
Key H = Histidine, Is= Isoleucine, Lu = Leucine, Ly = Lysine , Me = Methionine, Ph = Phenylalaine, Th = Threonine,
Tp = Tryptophan, Va = Valine; Al= Alanine; Gy = Glycine; Tyrozine, Ag =Arginine; As= Aspartic acid; Cy =
Cysteine, Gl = Glutamic acid, Pr = Proline, Sr = Serine; Ty = Tyrosine
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
377
Effect of processing variable of amino acid
of roasted breadfruit seeds
Basic amino acids (basic side chains at
neutral pH)
Histidine content of processed sample
ranged from 1.0 to 2.29g/16N. Roasting
temperature had significant effect on the
contents of histidine and accounted for
95% variations in histidine content.
Increases in temperature resulted in loses
of histidine. The maximum (68.35%) loss
occurred at 193.640C with less than 50%
of such losses occurring below 1600C. The
author [25] reported a lesser reduction of
16.5% for roasted groundnuts at similar
temperature.
The relationship between histidine content
and process variables is described by
equation 3.
His = 16.8033 + 0.153 X1- 0.005X1
2 - R2
(0.90) (3)
Lysine content in processed samples
ranged from 2.16 to 4.18g. Lysine content
of control was 7.10g/16g N. Roasting
condition was responsible for 90% per unit
change of lysine of processed seeds.
Simultaneous increases in roasting
temperature, time and feed quantity
resulted in losses of lysine with a
maximum (60.42%) loss observed at
193.64°C at 45min mark. The presence of
the highly reactive 6-HN2 group of lysine
may be responsible for observed
reductions in lysine value. Drawing from
the significant terms the relationship
between processed variables and lysine
content of samples can be written as:
Lys = 5.650 + 0.0418X1 – 0.1142X2 –
0.030X3 – 0.023X1X2- R
2 (0.90) (4)
The content of arginine in the processed
seed samples, varied between 3.17 to
5.62g/16g N which represents about 32 –
57.35% of the value of control. About
70.94% variation in arginine content was
attributable to their roasting condition.
However, no significant (p>0.05) effect of
roasting variables on arginine was
observed.
Acidic amino-acids (Acid side chains at
neutral pH)
Aspartic acid loss of processed seeds was
50% of its original content in control. The
maximum loss in value of aspartic acid
occurred at the extreme (193.64%)
temperature. All roasting variables showed
no significant effect on aspartic acid
content of roasted breadfruit seeds.
Glutamic acid was observed to be heat
susceptible with losses as much as 66.0%
of its initial value in raw samples
(19.50g/16g N) at 1200C -1400C. However,
as it was observed with aspartic acid,
roasting condition did not significantly
reduce glutamine acids. The most probable
reason could be an inherent ability of
certain amino acids to inhibit the Maillard
reactions.
Hydroxyl- containing amino acids
Threonine content of roasted seeds was
influenced by the processing conditions.
Though relatively heat stable at low
temperature, threonine showed significant
reductions at 1600C. Threonine content in
roasted seed sample ranged from 1.14g to
2.81g compared with 3.22g/16g N of
control. The significant effect of roasting
temperature and time on threonine can be
described using the equation.
Thre = 6.4176 – 0.0642X1 – 0.3954X2-
(R2) (0.85) (5)
Increasing roasting temperature and time
significantly influenced threonine content
by about 50%.
Serine content in roasted breadfruit seeds
showed losses attributable to roasting
variable conditions. Computed loss
variations showed a spread of between
1.47g to 3.9g/16g N, from 1230C to
193.640C, respectively.
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
378
Branched chain amino acids
Isoleucine content of roasted breadfruit
seed samples was between 1.30 and
3.11g/16gN. After processing isoleucine
content varied from 13. 61% to 63.88% of
control value (2.60g/16g N). The range of
losses of isoleucine in roasted breadfruit
seeds was comparable with the reports on
groundnuts (25) and Luffa seeds [26]. The
roasting variables showed linear and
interactive effects on isoleucine as:
Iso = 26.8837 – 1.0131X1 – 0.6994X2 –
0.0580X3 + 0.0185X1X2- .R
2 (0.83) (6)
Leucine was relatively more heat liable
than Isoleucine. Maximum loss (4.01g)
occurred at 193.640C which showed the
rate of change as each unit change of
process variable reflecting 72% variability
in leucine content of roasted samples. The
significant relationship between leucine
and process variables is expressed using
equation 7, as:
Leu = 62.3574 – 0.2441X1 – 1.5157X2 –
0.0188X1X2- R
2 (0.72) (7)
Neutral non polar amino-acids
Valine losses in roasted seeds were
between 35.55% and 54.89%. It was
observed that increases in roasting
temperature and time simultaneously
resulted in reduction of valine content of
samples. Roasting temperature and time
significantly influenced valine content in a
manner described by the equation:
Val = 24.9529 – 0.0489X1 – 0.7546X
2 +
0.0550X1X2- R
2 (0.79) (8)
Alanine and glycine contents of roasted
breadfruit seeds responded similarly to the
effect of processing variables.
Alanine in samples was reduced to about
43.5% at temperature range of 1600C and
1800C, respectively. Roasting variables of
temperature, time and feed quantity did not
significantly influence alanine contents of
seed samples.
Aromatic amino acids
Phenylalanine content in roasted seeds was
influenced by roasting variables. The
relationship between contents of
phenylalanine with roasting temperature,
time and feed quantity using significant
terms can be described by equation 9, as:
Phy = 19.3587 – 0.0919X1- 0.2623X2 –
0.850X3 + 0.290X1X2- R
2 (0.78) (9)
Increases in roasting temperature and time
resulted in linear, quadratic and interactive
effects. The linear and quadratic effect
occurred below 1600C. Above 1600C the
model described an interactive effect
between the roasting variables. A
maximum loss of 56.72% occurred at
193.64%.
Tyrosine content of control was 3.5g/16g
N. After roasting tyrosine values were
between 1.0 and 2.5g with a maximum loss
at 193.640C. Tyrosine values of roasted
seeds were related to processing conditions
without observing any significant influence
of roasting temperature, time and mass on
the tyrosine content. The range of losses of
tyrosine in breadfruit as observed by this
study is in agreement with the findings of
Passmore and Eastwood [27] in legumes.
Heterocyclic amino acids
Tryptophan content of raw unprocessed
seeds was 0.4g/16g N, but it was
undetected at processing temperatures
above 123.640C. Though breadfruit seeds
are low in tryptophan, the rapid reduction
observed for roasted breadfruit seeds could
be due to the highly reactive NH-group of
the inidole ring of tryptophan [28].
Proline content of processed samples
ranged from 1.21g to 4.9g/1.6gN (control).
Proline values were related to treatment
conditions but they were not significantly
(p>0.05) influenced by any processing
variable (Temperature, time and feed
quantity). Maximum loss (75.30%) of
proline occurred at 193.640C. Proline was
more heat sensitive than histidine.
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
379
Sulphur-containing amino acid
Methionine contents of processed seed
flour samples were influenced by roasting
temperature and time. The loss variations
of methionine depicted heat stability with
content of processed seeds ranging from
0.81 to 1.53g/16g N of control. The
summarization of the effects of roasting
temperature and time using significant
terms results in the equation 10 as:
Meth = 2.3326 – 0.0534X1 – 0.4203X2 –
0.0330X1X2- R
2 (0.93) (10)
Increase in roasting temperature and time
sequence resulted in initial linear effect up
to 1400C. The observed square effect
above that temperature was probably due
to the sustained oxidation of sulphur
fraction of methionine [28]. The result
contrasted with the reported ones for
methionine during roasting of legumes
[29].The cysteine content of control was
2.0g/16g N. After roasting the cysteine
content ranged between 0.45 and 1.50g
which showed a loss range of 33.04% to
67.12% of cysteine at extreme conditions
of 140°C to193.64°C. The results comply
with the heat stability of cysteine up to
1600C and plausible for the fact that
cysteine is limited in legumes. Although
the roasting variables had no significant
effect on cysteine values of processed
seeds, they significantly influenced similar
sulphur containing methionine content of
samples. The high toxicity risk factor of
methionine in muscular damage should be
a nutritional concern over high
consumption of roasted breadfruit snack
seeds.
The global optimum for process variables
and amino acids are summarized in Table
4. Optimum process variables resided at -1,
-1, 1 at the composite Desirability of 0.96.
The optimum variable combination was
142.450C (temperature) 40.12mm (time)
and 509.27g (feed quantity).
Table 4
Experimental and predicted optimum process variables for amino acids
Process variables Optimum values
Non-coded Coded
Roasting temperature (0C) 142.45 -1
Roasting time (min) 40.12 -1
Feed quantity (g) 509.29 1
Amino acids
Experimental (g/16gN) Predicted (g/16gN) RDA (mg/kg Adult)
Alanine 3.10 2.99
Arginine 5.62 4.87
Aspartic acid 6.10 7.03
Glutamic acid 8.21 9.11
Phenyalanine 4.05 3.98 3.0
Histidine 2.29 2.00 10.0
Gylcine 4.05 4.16
Lysine 4.27 4.19 30.0
Threonine 2.81 2.30 15.0
Methionine 0.75 0.89 4.1
Proline 3.01 3.2
Cysteine 0.95 1.02 0.4
Serine 3.63 4.10
Leucine 6.00 5.99 39.0
Isoleucine 3.10 4.03 20.0
Tyrozine 2.51 1.99 25.0
Valine 3.25 4.16 26.0
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
380
The predicted optimum total of amino
acids was 66.02% of control. For technical
convenience, the processed variables could
be adjusted to 140C, 40min and 500g. The
experimental and predicted values are
comparable (Fig.1). Hence the content of
amino-acids in roasted breadfruit as
revealed by the study satisfied about two-
thirds of the needed safe aggregates of
amino-acids for humans [30]
Fig 1: Total variation in different classes of
Amino acid of processed samples
Nutritional implication of amino-acid
profile of roasted snack seeds
The observed variations in amino acids are
indicative of the influence of processing
conditions on breadfruit seeds. Oxidation,
Maillard reaction and formation of cross
linkages involving amino acid side chains
are some of the reported reasons for
observed reductions of amino acid content
during heat processing [28]. The high
protein, carbohydrate [31] and anti-
nutrients [32] of breadfruit seeds infer the
concomitance of oxidation, Maillard
reaction and cross linking of the active
sites of amino acid side chains during dry
heat processing of breadfruit snack seeds.
The losses in amino-acid content are
comparable with values reported for
roasted groundnuts [25] bambara
groundnuts [33], cashew [34] benniseeds
[35] and sphenostylic stenocarpa [36].
Under optimum roasting conditions
(142.450C, 40.12mm500g) high contents
of arginine (5.62g), aspartic acid (6.102g),
glutamic acid (8.21g), leucine (6.0g) were
in agreement with the reported information
on those amino acids in the literature for
roasted leguminous seeds and nuts [37,
38,39,40]. Reports of studies under similar
roasting conditions showed that roasted
breadfruit seeds have higher content of
lysine, arginine, threonine, glycine and
serine than roasted groundnuts, almonds,
cashew and sphenostylis stenocarpa.
This study confirms the positive
correlation between heat susceptibility and
essential amino acids of roasted legumes
but disagreed with the changes in
methionine and threonine content of
roasted groundnuts as reported by
Anatharaman and Capenter [29]. The high
susceptibility of the sulphur fraction of
methionine and cysteine to oxidation
contests their finding on methionine.
The prominence of breadfruit roasted seeds
snack as an important source of amino-
acids needed for good health cannot be
contested. The safe concentration levels of
amino acids observed at optimum roasting
conditions are able to satisfy the RDA of
amino acids for humans. The presence of
histidine essential for infants and children
[41] phenylalanine an important
constituent of thyroid hormones,
methionine an antioxidant needed for
thiamine synthesis and mineral absorption,
lysine essential for tryptophan and niacin
metabolism, arginine an antioxidant
immune booster and vasodilator and
tyrosine need for neurotransmission and
hormonal synthesis point to the nutritional
importance of roasted breadfruit snack
seeds. The leucine-isoleucine ratio as
14.31
12.18
39.34
30.5
20.22
43.02
experment control
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
381
observed promotes the sustenance of the
complimentary role of leucine and
isoleucine as a protection against high
leucine induced adverse mental and
physical disorder in population whose diets
contain more of breadfruit seeds [41,42]
The possibility of a nitrogen imbalance in
the amino acid pool resulting from low
lysine initiated pressure between
methionine and lysine is inhibited by the
high contents of methionine and lysine in
roasted breadfruit seeds.
Roasted breadfruit snack seeds would be
unable to satisfy the RDA of cysteine for
humans. The low glutamic acid content is
also a minus for the proper development of
skin and immune system in human [43,44]
However, the observed concentrations of
cysteine and glutamic acid of roasted
breadfruit seeds pose no adverse toxicity
risks of breadfruit to humans.
It could be inferred through observed
amino acid values that roasted snack seeds
of breadfruit are nutritionally more
wholesome in amino acid density, safety,
digestibility and toxicity as compared with
commonly consumed snack seeds of
roasted groundnuts, almonds, cashews,
sphenostylis stenocarpa and walnuts.
The important nutritional contributions of
roasted groundnuts, Bambara groundnuts,
almonds, cashews, sphenostylic stenocarpa
and walnuts are limited by their low
content of histidine, lysine, threonine,
glycine and leucine. Many physiological
diseases have been traced to the deficiency
of these important amino-acids in humans
and experimental animals. Moreover
infants and growing children would need
to consume large amounts of roasted
almonds, cashews, groundnuts or other
commonly consumed roasted snack seeds
in order to achieve their RDA for histidine.
While roasted breadfruit seeds are able to
deliver about 66% of total amino-acids,
almonds with their high content of 23g
glutamic acid, 0.26g tryptophan [37] can
only deliver 37.25% total amino acids for
humans. Walnuts, cashews, sphenostylis
sternocarpa and Bambara groundnuts can
only deliver between 11-24%, total amino-
acids on consumption.
The high content of glutamic acid and
aspartic acid in almonds, cashews and
walnuts are physiological risk factor for
the development of mental and physical
stressful conditions in humans. However
the ability of the human body to convert
glutamic acid to glutamine through the
glutamate ammonium ligase reaction
during trauma underscores the need for
high content of glutamic acids in diets.
Glutamine is rapidly depleted during
trauma [44] which emphasizes the need for
high glutamic acid in the body for the
maintenance of proper neurotransmission
and brain functions. The usefulness of high
glutamic acid in diet for the maintenance
of glutamine homeostasis during trauma
does not however challenge the findings
which associate high glutamic acid with
adverse neuro-physiological functions.
Under traumatic conditions roasted
almonds are snacks of choice.
Digestibility of amino acids in animal gut
is reduced by the presence of high lipid
and dietary fibers in the fed diets [45 ,46]
The reported lipid values in the literature
are 14-54% almonds [37], 34% groundnuts
[25],13% cashews [34] ,16% Bambara
groundnuts [33] as compared with 9 – 11%
of roasted breadfruit seeds [9,47,]. The
nutritional implication is that other roasted
snack seeds could potentially impair amino
acid digestibility in humans. Groundnuts
and almonds have higher soluble dietary
fibers (about 50% of their 3.5 -5% raw
fiber values) than breadfruit seeds. Soluble
fibers have higher impeding actions on
nutrient metabolism than other forms of
fibers. The inhibitory actions of lipid and
dietary fibers on nutrient metabolism occur
at the enzyme-nutrient interface, blocking
the active side chains and the promotion of
Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XVII, Issue – 4, 2018
Azubuike C UMEZURUIKE, Joel NDIFE,Chinwe NWACHUKWU, Characterization of effect of modulated dry heat processing
conditions on essential and non-essential amino acid profile of unseasoned breadfruit (v. Decne) snack seeds, Food and Environment Safety,
Volume XVII, Issue 4 – 2018, pag. 372 – 384
382
physical barriers at nutrient absorption
sites in humans. Another nutritional risk
factor for other roasted snack seeds is
atherogenesis [48].The atherogenic
implications of roasted nuts with high lipid
contents could probably be ameliorated by
the presence of high dietary fiber (9-13%)
in nuts. The presence of high fibers though
important in preventing atherogenic
reactions does not prevent the initiation of
the Maillard reaction during roasting and
the development of some undesirable
metabolites.
During roasting of seeds, the Maillard
reaction occurs between sugars and amino-
acids resulting in production of metabolites
and color development through different
biochemical reaction pathways.
Acrylamide, a carcinogenic toxic [49] has
been shown to get formed in food during
roasting [50]. Acrylamide accumulation in
roasted seeds is defined by roasting
temperature, time, seed architecture and
chemical composition of seeds [51]. High
fat content is a risk factor for accumulation
of acrylamide during the roasting process
[52]. Seed architecture on the other hand
influences heat transfer rates and substrate
interactions inside the seed. Thick seed
hull inhibits accumulation of acrylamide in
seeds transiting the acrolein metabolic
pathway [53,54]. High lipid contents of
roasted almonds, groundnuts, cashews and
walnuts are suggestive of high
accumulation of acrylamide in them. Also
the roasting of almonds or of walnuts
without shells offers no protection against
acrylamide accumulation. In addition to
these nutritional drawbacks of other snack
seeds and nuts, some studies have reported
walnuts, almonds, groundnuts and cashew
as major sources of food allergens [55]. No
such implicating reports for roasted
breadfruit seeds as allergenic to humans
have been documented.
4. Conclusion
The process parameters used in this study
demonstrated good performance. Identified
optimum process variables combination
occurred at about 1400C and 40min. Above
140° - 40 min. point, roasting of breadfruit
seeds results in significant reductions in
amino acid concentration to levels below
the values needed to satisfy the RDA of
amino acids for humans. The results of this
study are an important template for proper
dry heat processing of unseasoned
breadfruit seeds for human consumption as
snacks.
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