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R E S E A R C H A R T I C L E Open Access
Chemical composition of protein
concentrate prepared from Yellowfin tuna
Thunnus albacares roe by cook-dried
process
Hyun Ji Lee
1
, Sung Hwan Park
1
, In Seong Yoon
1
, Gyoon-Woo Lee
1
, Yong Jung Kim
2
, Jin-Soo Kim
2
and Min Soo Heu
1*
Abstract
Roe is the term used to describe fish eggs (oocytes) gathered in skeins and is one of the most valuable food
products from fishery sources. Thus, means of processing are required to convert the underutilized yellowfin tuna
roes (YTR) into more marketable and acceptable forms as protein concentrate. Roe protein concentrates (RPCs)
were prepared by cooking condition (boil-dried concentrate, BDC and steam-dried concentrate, SDC, respectively)
and un-cooking condition (freeze-dried concentrate, FDC) from yellowfin tuna roe. The yield of RPCs was in the
range from 22.2 to 25.3 g/100 g of roe. RPCs contained protein (72.3–77.3 %), moisture (4.3–5.6 %), lipid
(10.6–11.3 %) and ash (4.3–5.7 %) as the major constituents. The prominent amino acids of RPCs were aspartic
acid, 8.7–9.2, glutamic acid, 13.1–13.2, and leucine, 8.5–8.6 g/100 g of protein. Major differences were not observed in
each of the amino acid. K, S, Na, and P as minerals were the major elements in RPCs. No difference noted in sodium
dodecyl sulfate polyacrylamide gel electrophoresis protein band (15–100 K) possibly representing partial hydrolysis
of myosin. Therefore, RPCs from YTR could be use potential protein ingredient for human food and animal feeds.
Keywords: Protein concentrate, Roe, Yellowfin tuna, Chemical composition, Cook-dried process
Background
Yellowfin tuna Thunnus albacares is a large tuna species
found in the Pacific, Indian and Atlantic oceans. It is an
important component of tuna fisheries worldwide and is
one of the major target species for the tuna fishery in
the major oceans, and popularly catched marine fish
with annual availability of 44,013 t on overseas fishery in
Korea during 2013 (Ministry of Ocean and Fisheries
2014). It is used extensively in raw cuisine such as sushi
and sashimi. Byproducts such as scales, heads, skin, fat,
visceral, and roe are generated increasingly and dis-
carded as waste, without any attempt to recover the
essential nutrients (Chalamaiah et al. 2010). Among by-
products, roes are highly nutritious material rich in
essential fatty acids and amino acids (Heu et al. 2006;
Narsing Rao et al. 2012b). Fish roes are produced in
large quantities during the spawning seasons, which con-
stitute about 1–3 % of the weight of fish (Chalamaiah
et al. 2013; Klomklao et al. 2013; Intarasirisawat et al.
2011). Currently roe obtained from fish such as salmon,
cod, and pollock have a potential commercial market,
especially they have a higher demand in Asian countries
(Sathivel et al. 2009). Yellowfin tuna roe is an abundant
and underutilized byproduct that can be used as a
unique protein source (Heu et al. 2006). The roe can be
used to recover protein that may be converted into a
higher value food ingredient suitable for use as an emul-
sifier in food and feed systems (Sathivel et al. 2009).
Protein concentrates are widely used as ingredients in
food industry because of their high nutritional quality,
functional properties, high protein level and low content
of antinutritional factors (Cordero-de-los-Santos et al.
2005). Using fish proteins in powder form presents some
advantages since they do not require special storage
* Correspondence: heu1837@dreamwiz.com
1
Department of Food and Nutrition/Institute of Marine Industry, Gyeongsang
National University, Jinju 52828, Korea
Full list of author information is available at the end of the article
© 2016 Lee et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12
DOI 10.1186/s41240-016-0012-1
conditions and they can also easily be used as an ingre-
dient in foods (Pires et al. 2012). Drying preserves fish
by inactivation enzymes and removing the moisture
necessary for bacterial and mold growth (Bellagha et al.
2002; Bala and Mondol 2001; Duan et al. 2004).
Recently, protein concentrate preparation have been
reported for different protein sources such as roe of
Channa striatus and Lates calcarifer (Narsing Rao
et al. 2012a), byproducts of Alaska pollock (Sathivel
and Bechtel 2006), mrigal egg (Chalamaiah et al.
2013) and roes of hake and ling (Rodrigo et al. 1998).
Before the drying process, boiling and steaming of fish
improve their digestibility, enhances palatability, and
provide a safe eating by killing harmful bacteria, other
micro-organisms and parasites. Thus, means of process-
ing are required to convert the underutilized yellowfin
tuna roes into more marketable and acceptable forms as
protein concentrate. There is no information about pro-
tein concentrate by cook-dried process. The objectives
of this study were to investigate chemical characteristic
for protein concentrate from yellowfin tuna roe prepared
by cook-dried process and to identify possibility on
utilization of 2’nd byproduct. Hence, we expected that
full utilization for fish roe concentrate will be possible
by reducing the 2’nd byproduct wastage and environ-
mental pollution.
Methods
Raw material
Yellowfin tuna Thunnus albacares roe was obtained
from Dongwon F&B Co., Ltd. (Changwon, Korea). Roe
was stored at −70 °C in sealed polyethylene bags, and
transferred to the laboratory. Frozen roe was partially
thawed for 24 h at 4 °C and then cut into small pieces
with an approximate thickness of 1.5–3 cm and minced
with food grinder (SFM-555SP, Shinil Industrial Co.,
Ltd., Seoul Korea). Minced roe was frozen at −20 °C
until used.
Chemicals
Sodium dodecyl sulfate (SDS) and glycine were purchased
from Bio Basic Inc., (Ontario, Canada). Coomassie Brilliant
Blue R-250 was purchased from Bio-Rad Laboratories
(Hercules, CA, USA). Bovine serum albumin (BSA), β-Mer-
captoethanol (β-ME), egg white, glycerol, N,N,N′,N′-tetra-
methyl ethylene diamine (TEMED), sodium carbonate,
sodium hydroxide, sodium L-tatarate, and potassium
hydroxide were purchased from Sigma-Aldrich Co., Ltd.
(St. Louis, MO, USA). Copper (II) sulfate pentahydrate was
purchased from Yakuri Pure Chemicals Co., Ltd. (Kyoto,
Japan). Bromophenol blue and Folin-Ciocalteu’sreagent
were purchased Junsei Chemical Co., Ltd. (Tokyo, Japan).
All reagents used analytical grade.
Preparation of roe protein concentrates (RPCs)
300 g of frozen minced roe was put into pouch type tea
bag (polyethylene polypropylene, 16 × 14.5 cm) for
cook-dried process. Freeze-dried concentrate (FDC) as
an un-cooked sample was prepared using freeze dryer
(PVTFD50A, ilShinbiobase Co., Ltd., Dongducheon,
Korea). To prepare the boil-dried concentrate (BDC),
sample immerged in five volume of distilled deionized
water (DDW) and was boiled for 20 min after sample
core temperature was reached to 80 °C. In case of
steam-dried concentrate (SDC), sample was steamed for
20 min after sample core temperature was reached to
80 °C. Cooked (boiled or steamed) samples were dried at
70 ± 1 °C for 15 h using an incubator (VS-1203P3V,
Vision Scientific, Co., Ltd., Daejeon, Korea). Boil or
steam-dried samples were ground to powder using a
food grinder and sieved to pass through a 180 mesh to
obtained dehydrated RPCs. Grounded powders were re-
ferred to as BDC and SDC, respectively. During these
processes, cooking process drips such as boil-process
drip (BPD) and steam-process drip (SPD) were gener-
ated as the 2’nd byproduct. They were packed in plastic
bottles and stored at −20 °C for further experiments. A
flow chart for the preparation of roe protein concen-
trates (RPCs) is shown in Fig. 1.
Proximate composition
The proximate composition was determined according
to the AOAC method (AOAC 1995). Moisture content
Fig. 1 Flowchart of preparation of roe protein concentrates (RPCs)
prepared by cook-dried process
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 2 of 8
was determined by placing accurately weighed 0.2 g of
sample into an aluminum pan. Sample was dried in a
forced-air convection oven (WFO-700, EYELA, Tokyo,
Japan) at 105 °C until a constant weight was reached.
The ash content was determined by charring approxi-
mately 0.1 g of sample in a ceramic crucible over a hot
plate and then heating in a muffle furnace (Thermolyne
10500 furnace, a subsidiary of Sybron Co., Dubuque, IA,
USA) at 550 °C until a constant final weight for ash was
achieved. The total crude protein (nitrogen x 6.25) con-
tent of samples was determined using the semi-micro
Kjeldahl method. Protein concentration of cooking
process drips was determined by the method of Lowry
et al. (1951) using bovine serum albumin as a standard.
Total lipid content was determined according to the
Soxhlet extraction method. 5 g of sample was extracted
with dimethyl ether and performed for 30 min at a drip
rate of 10 mL/min. Total lipid content was determined
on a gravimetric basis and expressed as percent.
Total amino acid
Total amino acid analysis was conducted according to
AOAC method (AOAC 1995). The sample (20 mg) was
hydrolyzed with 2 mL of 6 N HCl at 110 °C for 24 h in
heating block (HF21, Yamoto Science Co, Tokyo, Japan)
and filtered out using vacuum filtrator (ASPIRATOR A-
3S, EYELA, Tokyo, Japan). Amino acids were quantified
using the amino acid analyzer (Biochrom 30, Bio-
chrom Ltd., Cambridge, United Kingdom) employing
sodium citrate buffers (pH 2.2) as step gradients. The
data are reported as g of amino acid per 100 g of
protein. Asparagine is converted to aspartic acid and
glutamine to glutamate during acid hydrolysis, so the
reported values for these amino acids (Asp and Glu)
represent the sum of the respective amine and amino
acid in the proteins.
Mineral
Analysis of iron (Fe), copper (Cu), manganese (Mn),
cadmium (Cd), nickel (Ni), lead (Pb), zinc (Zn), chro-
mium (Cr), magnesium (Mg), sodium (Na), phos-
phorus (P), potassium (K), calcium (Ca), and sulfur
(S) contents in sample was carried out using the in-
ductively coupled plasma optical emission spectropho-
tometry (OPTIMA 4300 DV, Perkin Elmer, Shelton,
Conn., USA). Briefly, teflon digestion vessel was washed
overnight in a solution of 2 % nitric acid (v/v) prior
to use.
Sample was dissolved in 10 mL of 70 % nitric acid.
The mixture was heated on the hot plate until diges-
tion was completed. The digested samples were added
in 5 mL of 2 % nitric acid and filtered using filter
paper (Advantec No. 2, Toyo Roshi Kaisha, Ltd.,
Tokyo, Japan). Sample was massed up to 100 mL
with 2 % nitric acid in a volumetric flask. Sample was
run in triplicate. The concentration of mineral was
calculated and expressed as mg/100 g sample.
Hunter color
Hunter color properties of samples were equilibrated to
room temperature for 2 h prior to the color measure-
ment. Colors were determined using color meter (ZE-
2000, Nippon Denshoku Inc., Japan). The colorimeter
was calibrated by using a standard plate (L* = 96.82,
a* = −0.35, b* = 0.59) supplied by the manufacturer.
The values for the CIE (Commission Internationale
d’Eclairage of France) color system using tristimulus
color values, L* (lightness), a* (redness), and b*
(yellowness) were determined. The whiteness was cal-
culated by the following equation:
White index ¼100−ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
100−LðÞ
2þa2þb2
q
SDS-PAGE
The molecular weight distribution of YTR and RPCs
was observed by sodium dodecyl sulfate polyacrylamide
gel electrophoresis (SDS–PAGE). It was performed ac-
cording to the method of Laemmli (1970). Briefly, 10 mg
of sample was solubilized in 1 mL of 8 M urea solution
containing 2 % β-mercaptoethanol and 2 % sodium do-
decyl sulfate (SDS) solution. Protein solution was mixed
at 4:1 (v/v) ratio with the SDS-PAGE sample treatment
buffer (62.5 mM Tris–HCl (pH 6.8), 2 % SDS (w/v),
10 % glycerol, 2 % β-mercaptoethanol and 0.002 % bro-
mophenol blue) and boiled at 100 °C for 3 min. The
sample (20 μg protein) was loaded on the 10 % Mini-
PROTEAN® TGX™Precast gel (Bio-Rad Lab., Inc.,
Hercules, CA, USA) and subjected to electrophoresis at
a constant current of 10 mA per gel using a Mini-
PROTEAN tetra cell (Bio-Rad Lab., Inc., Hercules,
CA, USA).
Electrophoresed gel was stained in 0.125 % Coomassie
brilliant blue R-250 and destained in 25 % methanol and
10 % acetic acid until background was clear. Molecular
weight of protein bands was estimated using Precision
Plus Protein™standards (10–250 K, Bio-Rad Lab., Inc.,
Hercules, CA, USA).
Statistical analysis
All experiments were conducted in triplicates. The
average and standard deviation were calculated. Data
were analyzed using analysis of variance (ANOVA)
procedure by means of the statistical software of SPSS
12.0 KO (SPSS Inc., Chicago, IL, USA). The mean
comparison was made using the Duncan’smultiple
range test (P<0.05).
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 3 of 8
Results and discussions
Proximate composition
Proximate compositions of yellowfin tuna roe (YTR) and
roe protein concentrates (RPCs) named freeze-dried
concentrate (FDC), boil-dried concentrate (BDC) and
steam-dried concentrate (SDC) are shown in Table 1.
YTR as a raw material contained 77.3 % moisture,
18.2 % protein, 2.4 % lipid and 1.5 % ash. Heu et al.
(2006) reported that skipjack and yellowfin tuna roes
contained 71.1–71.2 % moisture, 21.4–21.5 % protein,
2.0–2.1 % lipid and 1.9 % ash, and both tuna roes were
no difference in proximate compositions. Intarasirisawat
et al. (2011) reported that three different tuna species
(skipjack, tongol and bonito) roes contained 72.17–
73.03 % moisture, 18.16–20.15 % protein, 3.39–5.68 %
lipid and 1.79–2.10 % ash. Iwasaki and Harada (1985)
described the proximate composition of raw roe from
different species with a wide range in protein content
(11.5 % in angler fish to 30.2 % in crab). The chemical
composition of roes of 18 fish species was reported and
the protein content was estimated to be in the range of
11.5–30.2 % (Iwasaki and Harada 1985). Therefore,
yellowfin tuna roe could be source of proteins. The yield
of RPCs prepared from YTR were 25.3 % for FDC,
22.2 % for BDC and 22.8 % for SDC, respectively, and
uncooked FDC was higher than those of cooked BDC
and SDC (P< 0.05). It was due to released soluble pro-
tein and other compounds to process drip through
cook-dried process (boiling or steaming). Moisture and
ash content of RPCs ranged from 4.3 to 5.6 %, and 4.3
to 5.7 %, respectively. Lipid content in RPCs was in the
range of 10.6–11.3 %. RPCs had a high protein content
accounting for 72.3 % for FDC, 77.3 % for BDC and
76.0 % for SDC, but RPCs were lower protein content
than 81.4 % egg white as a positive control (P< 0.05).
From the result and reports, difference in moisture and
protein content of RPCs was due to processing condition
(Mahmoud et al. 2008). Narsing Rao et al. (2012a) was
reported that Channa and Lates roes yielded 20.7 % and
22.5 % of protein concentrates possessing 90.2 % and
82.5 % protein, respectively. Protein content in the range
of 39.1–43 % and fat content in the range of 14.1–
14.8 % were reported in dried and salted roes of hake
(Merluccius merluccis) and ling (Molva molva) (Rodrigo
et al. 1998). Sathivel et al. (2009) was reported that
moisture, protein, ash, and fat contents of spray dried
soluble protein powder were 4.5 ± 0.5 %, 67.1 ± 0.2 %, 10
± 1.0 %, and 18.3 ± 0.6 %, respectively. Chalamaiah et al.
(2013) was reported that total ash content of dehydrated
and defatted protein concentrates was found to be
5.95 % and 1.95 %, respectively.
During the preparation of yellowfin tuna roe concen-
trate, boiling process drip (BPD) and steaming process
drip (SPD) as 2’nd byproduct were generated through
cooking process, and data are shown in Table 2. Mois-
ture content of BPD (92.0 %) was higher than that
(90.5 %) of SPD (P< 0.05). Protein content of BPD and
SPD were 5.8 and 6.4 %, respectively with no significant
difference. Starting process water (600 mL) for cooking
process was concentrated to 29.6 (BPD) and 18.1 mL
(SPD), respectively. Total protein in BPD (500.2 mg/
100 g roe) and SPD (365.6 mg/100 g roe) were meaning-
ful difference. This means that boiling process could be
easier released to soluble protein and other compounds
than steaming process. The proximate composition of
fish roe depends on the age of fish, seasons and type of
processing (Iwasaki and Harada 1985).
Total amino acid
YTR and RPCs contained protein ranged from 81.6 to
83.6 % on a dry base were still a considerable amount of
fish protein that could be possible to use as protein re-
source. To assess protein quality, we determined the
content of total amino acid in the YTR and RPCs. Total
amino acid composition (g/100 g of protein, %) of RPCs
from yellowfin tuna roe and positive control (egg white)
is shown in Table 3. The major non-essential amino
acids of YTR were glutamic acid (12.3 %), aspartic acid
(9.1 %) and arginine (6.6 %), respectively. Leucine
(8.8 %) and lysine (8.5 %) were the major essential amino
acids in YTR. Intarasirisawat et al. (2011) reported that
leucine (8.28–8.64 %) and lysine (8.24–8.30 %) were the
Table 1 Proximate composition of yellowfin tuna roe (YTR) and roe protein concentrates (RPCs) prepared by cook-dried process
Sample Yield
1)
(g) Protein yield
2)
(g) Moisture (%) Protein (%) Lipid (%) Ash (%)
YTR 100.0 18.2 77.3 ± 0.1 18.2 ± 0.0 2.4 ± 0.1 1.5 ± 0.2
FDC 25.3 18.3 4.3 ± 0.1ab 72.3 ± 0.4c 10.6 ± 0.1a 5.7 ± 0.5a
BDC 22.2 17.2 4.8 ± 0.1a 77.3 ± 1.4b 11.3 ± 0.5a 5.0 ± 0.9a
SDC 22.8 17.3 5.6 ± 1.0a 76.0 ± 1.9b 10.6 ± 0.3a 4.3 ± 0.2a
Egg white 3.0 ± 0.6b 81.4 ± 0.5a
Data are given as mean values ± SD (n=3)
Values with different letters within the same column are significantly different at P< 0.05 by Duncan’s multiple range test
FDC freeze-dried concentrate, BDC boil-dried concentrate, SDC steam-dried concentrate, respectively
1)
Yield is weight (g) of roe protein concentrate obtained from 100 g of raw YTR
2)
Protein yield (g) = yield x prote in (%)
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 4 of 8
predominant essential amino acids in defatted tuna roe
from skipjack, tongol and bonito. YTR had an essential
amino acids/non-essential amino acids ratio of 1.11.
From these results, total essential amino acids content of
YTR (52.6 %) was higher than total non-essential amino
acids content of that (47.4 %). The major non-essential
amino acids of RPCs were glutamic acid (13.1–13.2 g/
100 g of protein), aspartic acid (8.7–9.2 %) and arginine
(6.5–6.6 %), respectively. Among RPCs, glutamic acid
(13.1–13.2 %) was the predominant essential amino acid
followed by aspartic acid (8.7–9.2 %), leucine (8.5–8.6 %)
and lysine (8.5 %). Amino acids namely glutamic acid
(13.14 g), aspartic acid (8.08 g) and leucine (7.57 g) were
reported per 100 g roe protein of Channa roe protein
concentrate (Narsing Rao et al. 2012a).
RPCs had essential amino acid/non-essential amino
acid ratio in range of 1.00–1.06. From this result, essen-
tial amino acid/non-essential amino acid ratio of PRCs
was lower than that (1.10) of egg white, but it was simi-
lar to the value reported Heu et al. (2006) for yellowfin
tuna roe. Lysine is often considered a first limiting
amino acid for cereal food. Therefore, it needs to be
Table 2 Moisture and protein content of process drips obtained from yellowfin tuna roe during cook-dried process
Sample Moisture (%) Protein (%) Volume (mL/100 g roe) Protein
a
(mg/mL) Total protein (mg)
BPD 92.0 ± 0.1a 5.8 ± 0.0a 29.6 16.9b 500.2
SPD 90.5 ± 0.7b 6.4 ± 0.5a 18.1 20.2a 356.6
Data are means ± standard devia tion of triplicate determinations
Values with different letters within the same column are significantly different at P< 0.05 by Duncan’s multiple range test
BPD boiling process drip, SPD steaming process drip, respectively
a
Based on Lowry’s method (1951)
Table 3 Total amino acid composition (g/100 g protein, %) of yellowfin tuna roe (YTR) and roe protein concentrates (RPCs)
prepared by cook-dried process
Amino acid YTR FDC BDC SDC Egg white
Protein content (%) 82.4 81.6 82.6 83.6 83.9
Asp 9.1b 8.7c 9.0b 9.2b 11.8a
Thr
∮
5.2a 5.0c 5.1b 5.2a 4.7d
Ser 4.9e 5.6b 5.3d 5.4c 5.7a
Glu 12.3e 13.1d 13.2b 13.2c 14.9a
Pro
†
6.5a 6.1ab 5.8b 5.8b 3.7c
Gly
†
5.6a 4.9b 5.1b 5.1b 4.0c
Ala
†
5.6b 6.6a 6.4a 6.4a 6.6a
Cys 0.8a 0.7a 0.7b 0.8a 0.7a
Val
∮†
5.9c 6.3b 6.5b 6.4b 8.2a
Met
∮†
4.0a 2.9b 2.9c 2.8b 2.0c
Ile
∮†
5.9b 5.4c 5.5c 5.4c 6.2a
Leu
∮†
8.8b 8.6c 8.6c 8.5c 9.2a
Tyr 2.5c 3.4a 3.1b 3.0b 0.2d
Phe
∮†
4.3e 4.4d 4.6b 4.6c 6.4a
His
∮
3.4a 3.4a 3.2b 3.2b 2.7c
Lys
∮
8.5a 8.5a 8.5a 8.5a 8.2b
Arg
∮
6.6a 6.6a 6.6a 6.5a 4.8b
TAA 99.9 100.2 100.1 100.0 100.0
EAA 52.6 51.1 51.5 51.1 52.4
EAA/NEAA 1.11 1.04 1.06 1.00 1.10
Hydrophobic amino acid 46.6 45.2 45.4 45.0 46.3
Data are means ± standard devia tion of duplicate determination
Values with different letters within the same row are significantly different at P< 0.05 by Duncan’s multiple range test
TAA total amino acid, EAA essential amino acids, NEAA non essential amino acids
∮
Essential amino acids for infant
†
Hydrophobic amino acids
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 5 of 8
emphasized that the RPCs had a higher content of lysine
(8.5 %) than egg white (8.2 %) (P< 0.05). The lysine con-
tent of RPCs was 8.5 % which was higher than that
reported for Channa (6.94 %) and Lates (6.86 %) roe
protein concentrate (Narsing Rao et al. 2012a).
YTR and RPCs had hydrophobic amino acids ranged
from 45.0 to 46.6 %. Hydrophobicity plays an important
positive role in determining emulsifying properties
(Chalamaiah et al. 2013). FitzGerald and O’Cuinn (2006)
reported that bitterness of protein hydrolysate is associ-
ated with the release of peptides containing hydrophobic
amino acid residues. Thus, RPCs could possibly be a
dietary protein supplement to poorly balanced dietary
proteins exhibiting to low bitterness.
Mineral
Mineral (K, S, Na, P, Fe, Mg, Zn, Ca, Fe, Mn, Cu, Pb,
Cd, Cr and Ni) composition was determined to identify
the nutritional properties as a food compounds. Mineral
content of YTR and RPCs is presented in Table 4. K
content was the most predominant mineral in YTR
(456.0 mg/100 g of sample), followed by P, Na and Mg
(437.0, 167.0 and 29.0 mg/100 g, respectively). Minor
minerals were Ca and Zn (11.0 and 8.0 mg/100 g, re-
spectively). Heu et al. (2006) reported that predominant
mineral in YTR was P (371.5 mg/100 g) followed by K
and Ca (325.4 and 61.9 mg/100 g, respectively). Na con-
tent of YTR (167.0 mg/100 g) was very lower than that
(2473 and 2348 g/100 g, respectively) of dried salted roes
of hake Merluccius merluccius and ling Molva molva
reported Rodrigo et al. (1998). This high Na content is clearly
due to the salting process used to obtain the commercial prod-
uct. FDC had significantly higher K, Na and P content (1179.9,
376.2 and 257.7 mg/100 g of sample, respectively) compared
with those of BDC and SDC (P< 0.05). Similar K, P and Na
contents in defatted-tuna roes were found in salmon roe
(Bekhit et al. 2009). P content has been generally associated
with the phospholipid content and the presence of phospho-
protein (Mahmoud et al. 2008; Matsubara et al. 2003). The
highest S content was found in egg white (1341.3 mg/100 g)
as a positive control (P< 0.05). Bekhit et al. (2009) reported
that salmon roe had S content of 1647–2443 mg/kg (wet
basis). Catfish roe protein powder had S content of approxi-
mately 0.56 mg/kg (Sathivel et al. 2009). The result implied
that tuna roe had a high content of sulfur-containing com-
pounds, which could undergo decomposition during storage,
causing off-odor. Fe (9.7–12.9 mg/100 g of sample), Cu (0.4–
0.5 mg/100 g of sample), Mn (0.1–0.2 mg/100 g of sample)
andMg(59.1–70.6 mg/100 g of sample) were minor minerals
in RPCs. Fe and Cu are classified as the essential trace
elements required for physiological and metal metabolic pro-
cesses of marine organisms (Thanonkaew et al. 2006). Metal
ions (Fe, Cu, Mn and Mg) might serve as catalysts for lipid
oxidation, and have been shown to exhibit pro-oxidant activity
(Thanonkaew et al. 2006). However, Fe and P contents of all
samples were lower than those of catla, carp and rohu roes
(Balaswamy et al. 2009). The variation in the mineral compos-
ition of marine foods is closely related to seasonal and bio-
logical differences, area of catch, processing methods, food
source and environmental conditions (salinity, temperature
Table 4 Mineral contents (mg/100 g sample) of yellowfin tuna roe (YTR) and roe protein concentrates (RPCs) prepared by cook-dried process
Sample YTR FDC BDC SDC Egg white
Moisture (%) 77.3 4.3ab 4.8a 5.6a 3.1b
Mineral K 456.0 ± 2.0c 1179.9 ± 8.3a 761.6 ± 67.4b 758.9 ± 200.3b 787.0 ± 13.2b
S–992.3 ± 92.6b 858.2 ± 10.3c 818.1 ± 141.8bc 1341.3 ± 1.2a
Na 167.0 ± 1.0d 376.2 ± 2.1b 287.2 ± 17.5c 268.3 ± 55.5c 1015.8 ± 8.8a
P 437.0 ± 3.0a 257.7 ± 2.8b 223.4 ± 13.4c 208.5 ± 35.2c 92.5 ± 0.4d
Mg 29.0 ± 0.0c 66.8 ± 0.4a 70.6 ± 2.5a 59.1 ± 7.7a –
Zn 8.0 ± 0.0c 45.0 ± 0.3b 49.9 ± 0.4a 48.4 ± 3.5a –
Ca 11.0 ± 0.0c 33.5 ± 0.3b 58.6 ± 12.2a 32.3 ± 3.7b 65.2 ± 0.6a
Fe –9.8 ± 0.1b 12.9 ± 0.2b 9.7 ± 0.8ab 0.6 ± 0.0a
Mn –0.1 ± 0.0a 0.2 ± 0.0b 0.1 ± 0.0b 0.0 ± 0.0b
Heavy metal Cu –0.5 ± 0.0a 0.5 ± 0.1a 0.4 ± 0.1a 0.1 ± 0.0b
Pb –0.2 ± 0.1a 0.1 ± 0.0a 0.3 ± 0.1a 0.0 ± 0.0a
Cd –0.1 ± 0.0a 0.1 ± 0.0a 0.1 ± 0.0a 0.0 ± 0.0b
Cr –0.1 ± 0.0a 0.2 ± 0.1a 0.2 ± 0.1a 0.1 ± 0.0a
Ni –0.0 ± 0.0a 0.1 ± 0.1a 0.0 ± 0.0a 0.0 ± 0.0a
–; not determined
Data are means ± standard devia tion of three samples
Values with different letters within the same row are significantly different at P< 0.05 by Duncan’s multiple range test
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 6 of 8
and contaminant) (Alasalvar et al. 2002). According to Korean
Food Standards Codex, Pb and Cd do not exceed 0.5 and
0.1 mg/kg for fish roe. YTR and RPCs could serve as safety
and mineral source.
Hunter color
RPCs were light yellow in color and the L, a, b values
are listed in Table 5. FDC was the lightest with L* value
of 59.2. L* value of BDC and SDC (55.7 and 55.4, re-
spectively) were no significant (P> 0.05). a* value of
FDC (6.5) was higher than that of BDC (5.2) and SDC
(5.3). FDC had the highest b* value (18.6) than that (17.8
and 17.4, respectively) of BDC and SDC (P<0.05). How-
ever, total color change (ΔE) value is not significantly dif-
ference among the RPCs. (P> 0.05). Whiteness values of
FDC (54.7), BDC (52.0) and SDC (51.8) were observed
with no significant (P> 0.05). Sathivel et al. (2009) re-
ported that the catfish roe soluble protein powder was
light and yellow in color (L* = 71.7; a* = 3.9; b* = 28.8).
SDS-PAGE
SDS-PAGE patterns of FDC, BDC and SDC prepared from
yellowfin tuna roe and their 2’nd byproduct (BPD and
SPD, respectively) are shown in Fig. 2. Actinin band of
FDC was observed around 120 K. The major bands of
FDC observed at molecular weight around 97 K. FDC ex-
hibited two clear protein bands in the range of 75–100 K.
Protein bands at approximately 97 K could be vitellin like
protein, which was found in skipjack, tongol, bonito roes
(Intarasirisawat et al. 2011), chicken egg yolk (DeMan
1999) and salmon Oncorhynchus keta and sturgeon
Acipenser transmontanus roes (Al-Holy and Rasco 2006).
Protein bands in range of 50–37 K and 15 K were ob-
served. They could be the actin, troponin-T and myosin
light chain (MLC), respectively. Protein bands of egg white
(EW) were observed that in range of 75–100 K, 37–50 K
and around 15 K, respectively. More clearance actin band
wasobservedonEWthanthatofFDC.Whereas,vitellin
like protein band of FDC was more clear than that of EW.
SDS-PAGE patterns observed for BDC and SDC were
comparable. Above 250 K of protein band was clearly
observed on BDC and SDC. However, actinin was not
found both of them. Protein bands of 170, 95, and 55 K
was reported in Channa and Lates roe protein concentrate
(Narsing Rao et al. 2012a). Sathivel et al. (2009) observed
the presence of four abundant proteins with molecular
weights between 40 and 100 K in spray dried catfish roe
protein powder. The major bands of dehydrated and
defatted egg protein concentrates from mrigal observed oc-
curred at molecular weight (MW) of 97 K (Chalamaiah
et al. 2013). In case of BDC and SDC, band patterns in
range of 15–25 K more reduced than those of FDC.
Because association and aggregation of protein on low mo-
lecular protein was occurred due to cooking process which
caused protein degradation and soluble protein like a
sarcoplasmic protein was released from YTR. Released
soluble protein was found on BPD and SPD. Their major
protein band was 50 K. Low molecular soluble protein was
observed in range of 25–50 K caused by degradation of
high molecular protein.
Conclusion
Fish roe, a by-product in fishery industry, can be utilized
as a low cost source of protein for value addition. Pro-
duction of roe protein concentrate from yellowfin tuna
roe is a simple and economical process. This study dem-
onstrated that is feasible to produce concentrates from
yellowfin tuna roe by cook-dried process. The roe pro-
tein concentrates were found to be rich in protein with
essential amino acid. Fish roe protein concentrates may
potentially serve as a good source of protein with desir-
able functional properties. Therefore, these protein con-
centrates could be used as protein supplements and
functional ingredients in human diets.
Table 5 L*, a* and b* color values and whiteness of
concentrates (FDC, BDC and SDC) by cook-dried process
Hunter color FDC BDC SDC
L* 59.2 ± 0.1a 55.7 ± 3.7b 55.4 ± 1.9b
a* 6.5 ± 0.1a 5.2 ± 0.6b 5.3 ± 0.4b
b* 18.6 ± 0.0a 17.8 ± 0.1b 17.4 ± 0.1c
ΔE 42.3 ± 0.1a 45.0 ± 3.4a 45.1 ± 1.8a
Whiteness 54.7 ± 0.1a 52.0 ± 3.5a 51.8 ± 1.8a
Data are means ± standard devia tion of triplicate determinations
Values with different letters within the same row are significantly different at
P< 0.05 by Duncan’s multiple range test
Fig. 2 SDS-PAGE patterns of roe protein concentrates (RPCs) and
roe process drips prepared from yellowfin tuna roe
Lee et al. Fisheries and Aquatic Sciences (2016) 19:12 Page 7 of 8
Competing interests
The authors declare that they have no competing interests.
Authors’contributions
HJL and SHP carried out the preparation of protein concentrates,
participated in the analysis of chemical compositions and drafted the
manuscript. ISY, G-WL and YJK participated in searching and screening
references and performed the statistical analysis and carried out the
SDS-PAGE. J-SK and MSH conceived of the study, and participated in its
design and coordination and helped to draft the manuscript. All authors
read and approved the final manuscript.
Acknowledgements
This research was supported by Basic Science Research Program through the
National Research Foundation of Korea(NRF) funded by the Ministry of
Education(NRF-2014R1A1A4A01008620).
Author details
1
Department of Food and Nutrition/Institute of Marine Industry, Gyeongsang
National University, Jinju 52828, Korea.
2
Department of Seafood Science and
Technology/Institute of Marine Industry, Gyeongsang National University,
Tongyeong 53064, Korea.
Received: 20 March 2016 Accepted: 1 April 2016
References
Alasalvar C, Taylor KDA, Zubcov E, Shahidi F, Alexis M. Differentiation of cultured
and wild sea bass (Dicentrarchus labrax): total lipid content, fatty acid and
trace mineral composition. Food Chem. 2002;79:145–50.
Al-Holy MA, Rasco BA. Characterisation of salmon (Oncorhynchus keta) and
sturgeon (Acipenser transmont anus) caviar proteins. J Food Biochem.
2006;30:422–8.
AOAC (Association of Analytical Chemists). Official Methods of Analysis. 16th ed.
Washington DC: Association of Analytical Chemists; 1995. p. 69–74.
Bala BK, Mondol MRA. Experimental investigation on solar drying of fish using
solar tunnel dryer. Drying Technol. 2001;19:427–36.
Balaswamy K, Prabhakara Rao P, Narsing Rao G, Govardhana Rao D, Jyothirmayi T.
Physicochemical composition and functional properties of roes from some
fresh water fish species and their application in some foods. J Environ Agric
Food Chem. 2009;8:704–10.
Bekhit A, Morton JD, Dawson CO, Zhao JH, Lee HYY. Impact of maturity on the
physicochemical and biochemical properties of chinook salmon roe. Food
Chem. 2009;117:318.
Bellagha S, Amami E, Farhat A, Kechaou N. Drying kinetics and characteristic
drying curve of lightly salted sardine (Sardinella aurita). Drying Technol. 2002;
20:1527–38.
Chalamaiah M, Narsing Rao G, Rao DG, Jyothirmayi T. Protein hydrolysates from
meriga (Cirrhinus mrigala) egg and evaluation of their functional properties.
Food Chem. 2010;120:652–7.
Chalamaiah M, Balaswamy K, Narsing Rao G, Prabhakara Rao PG, Jyothirmayi T.
Chemical composition and functional properties of mrigal (Cirrhinus mrigala)
egg protein concentrates and their application in pasta. J Food Technol.
2013;50:514–20.
Cordero-de-los-Santos MY, Osuna-Castro JA, Borodanenko A, Paredes-López O.
Physicochemical and functional characterisation of amaranth (Amaranthus
hypochondriacus) protein isolates obtained by isoelectric precipitation and
micellisation. Food Sci Technol Int. 2005;11:269–80.
DeMan JM. Proteins. In: DeMan JM, editor. Principles in Food Chemistry.
Gaithersburg: Aspen Publishers Inc.; 1999. p. 111–62.
Duan ZH, Zhang M, Tang J. Thin layer hot-air drying of bighead carp. Fish Sci.
2004;23:29–32.
FitzGerald RJ, O’Cuinn GO. Enzymatic debittering of food protein hydrolysates.
Biotechnol Adv. 2006;24:234–7.
Heu MS, Kim HS, Jung SC, Park CH, Park HJ, Yeum DM, Park HS, Kim CG and
Kim JS. Food component characteristics of skipjack (Katsuwonus pelamis)
and yellowfin tuna (Thunnus albacares) roes. J Kor Fish Soc. 2006;39:1–8.
Intarasirisawat R, Benjakul S, Visessanguan W. Chemical compositions of the roes
from skipjack, tongol and bonito. Food Chem. 2011;124:1328–34.
Iwasaki M, Harada R. Proximate and amino acid composition of the roe and
muscle of selected marine species. J Food Sci. 1985;50:1585–7.
Klomklao S, Benjakul S, Kishimura H. Optimum extraction and recovery of trypsin
inhibitor from yellowfin tuna (Thunnus albacores) roe and its biochemical
properties. Int J Food Sci Technol. 2013;49:168–73.
Laemmli UK. Cleavage of structural proteins during the assembly of the head of
bacteriophage T4. Nature. 1970;227:680–5.
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the
Folin phenol reagent. J Biol Chem. 1951;193:265–75.
Mahmoud KA, Linder M, Fanni J, Parmentier M. Characterisation of the lipid
fractions obtained by proteolytic and chemical extractions from rainbow
trout (Oncorhynchus mykiss) roe. Process Biochem. 2008;43:376–83.
Matsubara T, Nagae M, Ohkubo N, Andoh T, Sawaguchi S, Hiramatsu N. Multiple
vitellogenins and their unique roles in marine teleosts. Fish Physiol Biochem.
2003;28:295–9.
Ministry of Ocean and Fisheries. 2014. Yearbook of marine resource. Retrieved
from http://www.mof.go.kr/article/view.do?articleKey=5197&boardKey=32&
menuKey=396¤tPageNo=1. Accessed 26 Jan 2015.
Narsing Rao G, Balaswamy K, Satyanarayana A and Prabhakara Rao P. Physico-
chemical, amino acid composition, functional and antioxidant properties of
roe protein concentrates obtained from Channa striatus and Lates calcarifer.
Food chem. 2012a; 132:1171–1176
Narsing Rao G, Prabhakara Rao P, Satyanarayana A and Balaswamy K. Functional
properties and in vitro antioxidant activity of roe protein hydrolysates of
Channa striatus and Labeo rohita. Food Chem. 2012b;135, 1479–1484
Pires C, Costa S, Batista AP, Nunes MC, Raymundo A, Batista I. Properties of
protein powder prepared from Cape hake by-products. J Food Eng. 2012;
108:268–75.
Rodrigo J, Ros G, Periago MJ, Lopez C, Ortuiio J. Proximate and mineral
composition of dried salted roes of hake (Merluccius merluccius, L.) and
ling (Molva molva, L.). Food Chem. 1998;63:221–5.
Sathivel S, Bechtel PJ. Properties of soluble protein powders from Alaska pollock
(Theragra chalcogramma). Int J Food Sci Technol. 2006;41:520–9.
Sathivel S, Yin H, Bechtel PJ, King JM. Physical and nutritional properties of catfish
roe spray dried protein powder and its application in an emulsion system.
J Food Eng. 2009;95:76–81.
Thanonkaew A, Benjakul S, Visessanguan W, Decker EA. The effect of metal ions
on lipid oxidation, colour and physicochemical properties of cuttlefish
(Sepia pharaonis) subjected to multiple freeze-thaw cycles. Food Chem.
2006;95:591–9.
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