49
ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS
Volume LVIII 6 Numbe 5, 2010
THE EFFECT OF STORAGE ON THE AMINO
ACIDS COMPOSITION IN POTATO TUBERS
M. Če ná, S. K áčma
Recei ed: Ma ch 11, 2010
Abs ac
ČERNÁ, M., KRÁČMAR, S.: The eff ec o s o age on he amino acids composi ion in po a o ube s. Ac a uni .
ag ic. e sil ic. Mendel. B un., 2010, LVIII, No. 5, pp. 49–56
The aim o his s udy was o in es iga e he eff ec o s o age du a ion on amino acids con en in po a o
ube s. Tube s o six cul i a s we e s o ed o 16 weeks. C ude p o ein was de e mined by he Kjel-
dahl me hod. The amino acid con en was iden ifi ed a e acid hyd olysis; sulphu amino acids we e
oxidized wi h he mix u e o hyd ogen pe oxide, o mic acid and phenol. The essen ial amino acids
index and chemical sco e was calcula ed. The whole egg p o ein was used as e e ence p o ein. The e -
ec o s o age du a ion and cul i a on he o al amino acids con en was ound o be signifi can in all
po a o a ie ies. The le el o he o al amino acids con en s was de e mined wi hin he ange o 80–
87%. Simila downwa d end was obse ed in c ude p o ein. The essen ial amino acids index a ied
conside ably among he po a o cul i a s, anging om 42 o 57%. Sul u amino acids and isoleucin
we e he limi ing amino acids in all he in es iga ed ube s.
Solanum ube osum L., s o age, amino acid, p o ein, essen ial amino acids index
Po a o (Solanum ube osum L.) is a ypical c op g own
in many coun ies in Eu ope. In he Czech Republic
i is one o he mos impo an ho icul u al c ops.
Mo e han 753 housand ons o po a oes we e ha -
es ed in 2009 (ČSÚ, 2010). Po a oes a e o en pe -
cei ed as a me e s a ch sou ce, bu hey a e also ich
in mine als, i amins and p o ec i e subs ances. Po-
a oes a e used in die s, namely o hei good di-
ges i bi li y and a low alle gen po en ial. Food in o le-
an ce can be igge ed only by po a o p oduc s like
chips and c isps. I is a well known ac ha po a o
c ops p oduce a highe quan i y o p o ein pe hec -
a e han ce eals (FAO, 2009). Po a oes con ain abou
2% o c ude p o ein in esh ma e . Because o e-
la i e ly highe po a o consump ion (annually ap-
p ox. 70 kg pe capi a in he Czech Republic), po a o
ube s a e an impo an sou ce o p o ein in a hu-
man die . Howe e , he amoun o c ude p o ein de-
pends on cul i a , ag icul u al p ac ices and ag o-
clima ic ac o s. C ude p o ein includes a numbe o
ni ogen ac ion, amides and ee amino acids (Ep-
pendo e e al., 1979). Po a o p o ein is aluable o
a high biological alue. The biological alue o po a-
oes mixed wi h eggs eaches o he amoun o abou
140% o s anda d p o ein (Z ůs , 2004). The basic
ole o po a o p o ein in nu i ion is he con ibu ion
o suffi cien amoun s o essen ial amino acids o
p o ein endogenous syn hesis by human body. I is
essen ial o ake he diff e ence be ween nu i ional
and biological aspec s in conside a ion. The e o e
as a as biological aspec is conce ned, nonessen ial
amino acids a e mo e impo an han he essen ial
ones (Mu ay e al., 1998). Chemical sco e ob ained
by compa ing he limi ing amino acids in ela ion
o he e e ence p o ein is a chemical me hod which
efl ec s he p o ein quali y (F iedman, 1996).
To al amino acids con en mainly depends on
cul i a (Z ůs , 2004). P e ious s udies epo a-
iab le ends in ee amino acids con en s in po a o
du ing he s o age (Talley e al., 1984). Ce ain s u-
dies on he ee amino acid con en in s o ed po-
a o ube s ha e shown high alues o amide as pa-
a gi ne and glu amine in ube s (B ie ley e al., 1997).
Amino acids con en is associa ed wi h Milla d eac-
ion and ac ylamide o ma ion. Se e al s udies ha e
shown ha ac ylamide can be o med in Milla d e-
ac ion om aspa agine wi h ca bonyl compounds
(S adle e al., 2002; Zyzak e al., 2003; De Wilde e al.,
2005). The ela ionship among he quan i y o e-
ducing suga s, amino acids con en and ypical co-
50 M. Če ná, S. K áčma
lou o po a o p oduc s was in es iga ed by many e-
sea ches (Roe e al., 1990; B ie ley e al., 1996). Mos
s udies in he fi eld o amino acids con en in po-
a o ha e only ocused on he amoun o ee amino
acids. So a , he e ha e been only a ew discussions
abou he o al amino acids con en in s o ed po a o
ube s.
The pu pose o he p esen s udy was o de e -
mine he infl uence o s o age du a ion on he amino
acids con en , amino acids p ofi le and amino acid
sco e in six po a o a ie ies.
MATERIALS AND METHODS
S o age and sampling o po a o ube s
Po a oes (Solanum ube osum L.) we e g own in fi e
loca ions in he Czech Republic on he p emises o
AGRO-MĚŘÍN, a.s. Six po a o cul i a s wi h diff e-
en ma u i y class we e selec ed o he expe imen .
Cha ac e is ics o he cul i a s a e shown in Tab. I.
Win e ba ley (Ho deum ulga e) was used as a o e
c op. In he au umn, manu e was applied (45 . ha−1)
oge he wi h ni ogen (40.5 kg N.ha−1 o s aw de-
composi ion) and po assium e iliza ion. Plan s
we e g own using a s anda d comme cial p ac-
ice and a uni o m e iliza ion egime. Ni ogen,
po assium and phospho us e iliza ion, in doses
131 kg N.ha−1 (UREA S abil), 162 kg K.ha−1 (K2O) and
72 kg P.ha−1 (P2O5), we e used in he expe imen . Tu-
be s we e ha es ed in he pe iod om Augus ill
Oc obe 2008.
Randomly selec ed ube s we e s o ed in a s o-
a ge house (Beskyd F yčo ice, a.s., CZ) wi h an au-
oma ic ai -condi ioning con ol. Po a oes we e kep
a 3–6 °C and 80% RH in 20-kilog am boxes. Sp ou
o ma ion du ing he s o age was supp essed by
NEO-STOP L 300 ea men in he o m o gas. Tu-
be s we e sampled o analysis a 4-week in e als,
in o al pe iod o 16 weeks. Each mon h a sample
consis ing o wo 20-kilog am boxes was sen o la-
bo a o y analysis.
Abou wo kilog ams o heal hy ube s o each de-
li e y we e selec ed, ho oughly washed o emo e
soil pa icles, peeled and g ound. All he samples
we e kep a −80 °C and hen lyophilized a −4 °C,
12.156 Pa o 48 h (Ch is Alpha1–4 LSC, Labicom,
CZ) be o e he analysis.
To al ni ogen con en
To al ni ogen was de e mined by he mic o o
Kjeldahl me hod by an au oma ic P o-Ni o 130.
Con e sion ac o o 6.25 was used o he calcula-
ion o he c ude p o ein con en . Chemical analy-
ses we e epea ed fi e imes and he esul s we e ex-
p essed on 100% d y ma e basis (DM).
Amino acids analysis
To de e mine he fi  een amino acids (aspa -
ic acid, h eonine, se ine, glu amic acid, p o-
line, glycine, alanine, aline, isoleucine, leucine,
phenylalanine, y osine, his idine, lysine and a -
ginine), 0.1 g o lyophilized ube s was weigh ed
in o sc ew-capped ial. Amoun 15 ml o 6 mol . l−1
HCl was added in o a ial and he solu ion was
pu ged by a gon o 1 min. The ial was conse-
quen ly placed in a e m-block (Labicom, CZ) which
was hea ed o 115 °C and a sample was hyd olyzed
o 23 hou s. Then he ial was cooled down, HCl
was emo ed by a o a y a cuum e apo a o (RVO
400a, Ingos, CZ) and he opy esidue was quan i-
a i ely ans e ed in o he 25 ml olume ic fl ask
wi h sodium-ci a e buff e (pH 2.2). Fo he assess-
men o he sulphu amino acids (me hionine and
cys eine), 0.7 g o lyophilized ube s was oxidized in
hyd ogen pe oxide, o mic acid and phenol. Oxida-
ion was accomplished a 2 °C o 16 hou s (Offi cial
Jou nal o he Eu opean Union, 2009). The ollow-
ing p ocedu e was he same as ha o acid hy d o-
ly sis. The sample was fi l e ed h ough a 0.45 μm fi l-
e be o e using he analyze . Fo he assignmen o
amino acids, he ionic liquid ch oma og aphy wi h
sodium-ci a e buff e s, pos -column ninhyd in
de i a iza ion and spec opho ome ic de ec ion
(Amino Acid Analyze AAA 400, Ingos, CZ) was ap-
plied. Each sample was epea ed six imes and each
hyd olysa e was analyzed wice. The esul s we e ex-
p essed in 16 g N.
I: Cha ac e is ics o po a o samples
Va ie y Ma u ing Boiling ype Locali y GPS Plan ing Ha es
Angela VE B Žďá /Sáza ou 49°33´17´´N;
15°54´20´´E 17/05 29/08
P incess VE A K melín 49°44´07´´N;
18°14´03´´E 30/05 10/09
Ma abel E B Měřín 49°25´01´´N;
15°54´41´´E 20/05 15/08
Lau a E B Pasko 49°43´50´´N;
18°17´51´´E 15/05 09/10
Mil a SE AB Pasko 49°43´50´´N;
18°17´51´´E 10/05 04/09
Belana SE AB Pe ř ald 49°50´04´´N;
18°17´51´´E 12/05 04/10
VE – e y ea ly; E – ea ly; SE – semi-ea ly
The eff ec o s o age on he amino acids composi ion in po a o ube s 51
All esul s we e e alua ed using he a ia ion s a-
is ics, co ela ion ma ices and eg ession unc ions
we e calcula ed acco ding o Snedeco and Coch an
(1967) using he s a is ical package Unis a ( . 5.5).
RESULTS AND DISCUSSION
The changes in he sum o nonessen ial (∑NEAA),
essen ial amino acids (∑EAA) and o al amino acids
(∑AA) in po a o ube s o diff e en a ie ies du -
ing he 16-week s o age a e p esen ed in Tab. II.
The esul s demons a e ha he s o age du a-
ion has a signifi can infl uence on he amino acids
con en in all po a o a ie ies. A he beginning o
he s o age, he alue o ∑AA mo ed in he ange o
79.9–87.2 g/16 g N. The esul s ha e shown ha An-
gela a ie y con ained he maximum o o al amino
acids. A e 16-week s o age o he po a oes, he o-
al quan i y o amino acids dec eased app oxi-
ma ely by 20%. The highes loss in he o al amino
acids con en was obse ed in he po a o a ie y Be-
lana (28.4%), whe eas he lowes educ ion o ∑AA
(8.7%) was eco ded in Ma abel a ie y. Bo h a ie-
ies belong o ea ly po a o a ie ies. A conside able
all (27%) in ∑NEAA was ound in samples o P in-
cess a ie y, which was s o ed o 4 mon hs. Mino
educ ion in ∑NEAA esul ing om he s o age du-
a ion was obse ed in Ma abel a ie y. The highes
amoun o essen ial amino acids was ound in ube s
o ea ly a ie y Angela. Semi-ea ly a ie ies Ma abel
and Belana had compa able alues o ∑EAA. F om
he da a in Tab. II, i is appa en ha he amino acid
composi ion is signifi can ly infl uenced by po a o
a ie y. The e exis s a ce ain e idence ha he s o-
a ge ime sligh ly eff ec ed he amino acids con en
in ube o Ma abel a ie y, whe eas he alue o
he amino acids in Mil a a ie y was ma kedly in-
fl uenced by he s o age du a ion. Tab. III shows
he mean alue o chemical sco e (CS) and essen-
ial amino acids index (EAAI) o he es ed po a o
a ie ies. The chemical sco e wi h espec o he e-
e en ce pa e n (whole egg p o ein) was calcula ed
o each cul i a . A he beginning and a he end
o he s o age, he mean alue o he EAAI (con si-
de ing all he essen ial amino acids excep yp o-
phan) anged om 54–66 and 42–57%, espec i ely.
These esul s appea o be consis en wi h he p e-
iously published da a (So elo e al., 1998; Galdón e
al., 2010). The esea ches who used a e e ence p o-
ein (WHO/FAO) ound he alue o chemical sco e
o amino acids be ween 42–53%. Fu he , i is known
ha po a oes con ain a high amoun o lysine which
occu s a ely in plan p o eins. The highes amoun
o lysine was de e mined in Ma abel and Angela. A
he beginning o he expe imen , sulphu ic amino
acids (Cys+Me ) we e ound as limi ing amino acids
in all he samples excep Mil a. I his a ie y, iso-
leucine was ound as he fi s amino acid limi ing
he p o ein nu i ion alue. A e he 16-week s o-
a ge, Cys and Me we e epea edly de ec ed as li mi-
ing acids in he es ed a ie ies excep Angela a-
ie y which had isoleucin as he fi h and Cys and
Me as he second limi ing amino acids. Leucine was
he second limi ing amino acid o Mil a and isoleu-
II: Eff ec o 4-mon h s o age on he sum o nonessen ial, essen ial and o al amino acids in po a o ube s in g/16 g N
Va ie y Angela P incess Ma abel Belana Mil a Lau a
S o age
(mon h) 141414141414
∑NEAA 51.30 41.96 53.78 39.17 49.08 43.50 49.07 37.77 46.71 36.77 50.18 40.30
∑EAA 35.87 29.60 29.56 24.89 34.75 33.02 34.89 22.43 33.21 24.40 32.61 26.82
∑AA 87.16 71.56 83.34 64.06 83.83 76.52 83.96 60.20 79.92 61.17 82.79 67.18
III: Changes o Chemical sco e and Essen ial amino acids index in po a o ube s du ing 4-mon h s o age
Index Va ie y Angela P incess Ma abel Belana Mil a Lau a
EAA141414141414
CS
Th 69.2 54.6 64.3 41.2 69.2 60.8 61.1 54.6 64.3 41.6 60.3 41.9
Val 80.5 63.2 68.5 61.0 74.9 71.4 74.5 63.2 68.5 53.4 74.9 59.9
Leu 63.8 52.8 49.3 43.3 61.0 66.3 65.1 52.8 49.3 43.7 63.2 43.9
Ile 55.4 44.6* 44.9 40.8 50.6 50.8 53.6 44.6 44.9* 39.0 51.3 41.8
Lys 75.4 58.8 61.5 47.0 74.0 72.9 66.0 58.8 61.5 51.1 67.5 50.7
A g 67.1 57.4 51.1 52.2 67.7 51.3 80.1 57.4 51.1 48.7 54.0 68.9
His 63.1 53.2 61.7 53.5 66.6 64.5 62.7 53.2 61.7 50.2 61.2 58.9
Phe 67.7 54.9 55.8 45.5 66.1 65.6 65.7 54.9 55.8 45.6 62.5 48.1
∑Cys+Me 52.2* 52.4 41.0* 37.1* 50.1* 43.1* 49.1* 38.4* 50.1 34.4* 44.7* 38.8*
EAAI 66.1 53.8 54.1 44.4 61.0 56.9 60.5 55.8 54.1 42.4 57.5 47.6
CS – Chemical sco e
EAAI – Essen ial amino acids index
* – The fi s limi ed amino acid
52 M. Če ná, S. K áčma
cine o he es o he a ie ies. Suá ez-López e al.
(2006) ha e also ound a e y low le el o sul u ic
acids in he esea ch ha po a o p o eins con en .
Figu es 1–6 compa e he con en o o al amino
acids (AA) and c ude p o ein (CP) in diff e en po-
a o a ie ies du ing he s o age. A he beginning o
he s o age, he amoun o CP was in he ange om
8.9–11.9% o 100% DM. This fi nding is in an ag ee-
men wi h Galdón’s e al. (2010) esul s, whe e i is
men ioned ha c ude p o ein con en anged om
1.46–2.38% o he esh weigh . Simila esul s a e
men ioned by o he in es iga o s (Blenkinsop e al.,
2003). De Wilde’s e al. (2005) esea ch shows ha
c ude p o ein was ai ly cons an in ube s s o ed
o 24 weeks. Acco ding o ou esul s, longe s o-
a ge ime esul s in a dec ease o he con en o
amino acids and he simila downwa d end can
be seen in c ude p o ein. A e he 16-week s o a ge,
he amoun o CP and AA dec eased app ox. by 35
and 18%, espec i ely. A apid change in CP alue
(24%) was ound in he samples o Belana a ie y.
This a ie y showed he highes d op o o al amino
acids con en (46%). On he con a y, a sligh change
in he amoun o CP (10%) was obse ed in he u-
be s o Mil a a ie y and in he lowes all o AA
con en (29%) was ound in Ma abel a ie y. The e
exis s ce ain e idence ha he amino acids con en
and he quan i y o c ude p o ein a e aff ec ed by
he s o age ime and by he a ie y, bu no he same
way. Bá o á e al. (2009) s udied he eff ec o cul i-
a , locali y and ni ogen e iliza ion on c ude p o-
ein con en in ube s o s a ch p ocessing po a o.
Bá o á e al. show ha he mos impo an ac o a -
ec ing CP is he cul i a ha pa icipa ed in he o al
a iabili y wi h app oxima ely 34%.
0
2
4
6
8
10
12
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
1: E ec o s o age on alue o AA and CP (%) in ube s o Angela a ie y
0
2
4
6
8
10
12
14
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
2: E ec o s o age on alue o AA and CP (%) in ube s o P incess a ie y
The eff ec o s o age on he amino acids composi ion in po a o ube s 53
0
2
4
6
8
10
12
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
3: E ec o s o age on alue o AA and CP (%) in ube s o Ma abel a ie y
0
2
4
6
8
10
12
14
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
4: E ec o s o age on alue o AA and CP (%) in ube s o Belana a ie y
0
1
2
3
4
5
6
7
8
9
10
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
5: E ec o s o age on alue o AA and CP (%) in ube s o Mil a a ie y

54 M. Če ná, S. K áčma
CONCLUSION
This s udy has in es iga ed he infl uence o s o age and cul i a s on he amino acids con en . The e-
sul s o his in es iga ion demons a e ha he gene ic cha ac e is ics o po a o cul i a s infl uence
amino acids con en and he e o e hei nu i ion alue. Fu he mo e, longe ime o s o age caused
a educ ion o amoun o c ude p o ein and consequen ly he o al amino acids con en . Angela and
Belana a ie ies showed he bes amino acid p ofi les. In gene al, in case o amino acids amoun , Ma a-
bel a ie y appea s o be he mos esis an o he s o age ime. This s udy has shown ha all po a o
a ie ies had me hionine, cys eine and isoleucine as limi ing amino acids. Ne e heless, any quali y
e alua ion o p o ein has o ake in o accoun also diges ibili y o ha p o ein and hus subsequen ly
co ec also i s chemical sco e.
SOUHRN
Vli sklado ání na obsah aminokyselin hlízách b ambo
P áce sleduje li doby sklado ání na obsah aminokyselin hlízách b ambo . Šes od ůd b ambo
bylo sklado áno za s anda dních podmínek po dobu 16 ýdnů. Hlízy byly analyzo ány ždy po č y-
řech ýdnech. Byl zjiš ěn nega i ní li doby sklado ání na obsah aminokyselin. Na počá ku sklado-
acího pokusu se celko ý obsah aminokyselin pohybo al ozmezí 80–87 g/16 g N. Po č yřměsíč-
ním sklado ání bylo zaznamenáno snížení obsahu aminokyselin p ůmě u o 20 %. Podobný end
byl shledán i případě h ubého p o einu, jehož množs í se hlízách sklado aných 16 ýdnů sní-
žil p ůmě u o 17 %. Jako p ní limi ující aminokyseliny byly b ambo ách de eko ány si né ami-
nokyseliny cys ein a me hionin a dále isoleucin, k e ý byl zá o eň i d uhou limi ující aminokyse-
linou. Po použi í Scheff ého me ody bylo zjiš ěno ámci každé od ůdy, že sklado ání o li ňo alo
index esenciálních aminokyselin, jehož p ůmě né hodno y dosaho aly na počá ku sklado ání 58 %
a na konci sklado acího pokusu 51 %.
b ambo y, sklado ání, aminokyseliny, p o ein, index esenciálních aminokyselin
This esea ch is suppo ed by a p ojec o Minis y o Educa ion, You h and Spo s o he Czech Re-
public (G an No. MSM 7088352101). We would like o hank he company Beskyd F yčo ice, a.s.,
Czech Republic o g an ing he samples, he possibili y o po a o s o age in hei s o age house and
he assis ance in ube s deli e y.
0
2
4
6
8
10
12
04816
S o age (weeks)
To al amino acids/ C ude p o ein con en (%)
AA
CP
6: E ec o s o age on alue o AA and CP (%) in ube s o Lau a a ie y
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biochemie a analýzy po a in, Uni e zi a Tomáše Ba i e Zlíně, nám. T. G. Masa yka 5555/275, 762 72 Zlín,
Česká epublika, e-mail: ce na@ .u b.cz
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