the effect of inhibitors on the amino acid content in the stored potato

ZESZYTY PROBLEMOWE POSTĘPÓW NAUK ROLNICZYCH 2008 z. 530: 301-316
THE EFFECT OF INHIBITORS
ON THE AMINO ACID CONTENT IN THE STORED
POTATO TUBERS
Honorata Danilchenko, Rima Pranaitiene, Zivile Taraseviciene,
Egidija Venskutoniene
Lithuanian University of Agriculture, Kaunas, Lithuania
Introduction
The content of amino acids in potato tubers depends mostly on the potato cultivar
characteristics as well as on the growing and storing conditions [EPPENDORFER, EGGUM
1994]. Among others, the most valuable are essential amino acids: treonine, valine,
methionine, isoleucine, leucine, fenilalanine, histidine, lysine, arginine. These essential
amino acids available in proteins make them complete, therefore potatoes are important
for protein balance in human diet. The highest amount of amino acid is in potato tuber
centre [LESZCZYŃSKI 2000]. Changes in protein content occurring during storage are the
effect of the amount of amino acid increase process [MIETLICKI et al. 1984]. Some authors
state that during storage the amount of amino acids increases and the major part of free
amino acid consists of glutamic and asparagine acids [BRIERLEY et al. 1996; CIEŚLIK,
PRAZNIK 1997; YANG et al. 1999]. Some authors [CIEŚLIK, PRAZNIK 1997] claim that the
increase of the amino acid content in potato tubers depends on their sprouting, whereas
others [BRIERLEY et al. 1996], indicate that during storage the change of amino acids are
influenced by various factors including the changes in the protein content and free
amino acids.
Materials and methods
The research was carried out in 2002-2006 at the Crop-Growing Product Storage
and Processing Laboratory in the Department of Horticulture of Lithuanian University
of Agriculture Animal Husbandry Institute of Lithuanian Veterinary Academy.
To show the potato sprouting during storage, essential oils of caraway
cv. Gintaras and dill cv. Grybovskij with s-carvone as the active agent were used. The
ether content of caraway seeds and dill seeds was 2.23% and 2.45% respectively. For
one ton of potato tubers, essential oils of caraway and dill seeds produced from 1 kg of
raw material by distilling with water vapor were used. 1% water solution was made
from essential oil intensely which mixed was evenly sprayed onto potato tubers. During
storage potato tubers were sprayed with inhibitors twice, i.e. at the beginning of October
and at the beginning of January.
For comparison, the chemical inhibitor CIPC containing chloropropham, widely
applied in industry, was used. The recommended amount of this inhibitor is 1 kg for 1
ton of potatoes. Potato tubers were treated with the chemical inhibitor only once, at the
beginning of October. Test variants: K - untreated variant - tubers were not treated with
inhibitor materials during storage; KM - tubers treated with the essential oil of caraway
H. Danilchenko et al.
302
seeds; KR - tubers treated with the essential oil of dill seeds; C - tubers treated with the
inhibitor CIPC.
For the experiment the potato tubers of every variant were sacked separately by 5
kg (four replications for storage studies and four replications for studies of the quality of
raw material and processed products) into polyethylene bags of 120ě thickness (in order
for the essential oil not to evaporate). Potato tubers of every variant were stored for
eight months (from September until May) in refrigerating cabinets of KX-_ type with
automatic temperature control at 9°C (± 0.5°C) and 90-95% relative humidity. Each test
variant of the examined potatoes was stored in separate cabinets.
Amino acid contents were determined before and after 5 and 8 months of storage.
All chemical analyses were carried out in two replications. Amino acids were disjoined
by the method of ion-exchange chromatography.
Data was statistically analysed using the StatSof data analysis and management
module of the integrated system STATISTICA. For the evaluation of potato tuber
preservation, chemical analysis and quality of processed products one- or two-factor
dispersion analysis was carried out. Averages of separate variants were calculated,
standard deviation, the least significant difference at the 95% probability level was
estimated by using the Fisher’s LSD test (P < 0.05).
Results and discussion
15 amino acids were determined including 9 essential amino acids (Fig. 1).
Glutamic acid and aspartic acids (asparagines) make up 33-50% of all of amino acids.
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Goda
Gloria
Nida
Vaiva
Vok÷
arginine; arginina
lysine; lizyna
histidine; histydyna
fenilalanine; fenyloalanina
tyrosine; tyrozyna
leucine; leucyna
isoleucine; izoleucyna
methionine; metionina
valine; walina
alanine; alanina
glycine; glicyna
glutamic acid; kwas glutaminowy
serine; seryna
treonine; treonina
aspartic acid; kwas asparaginowy
Fig. 1. The amino acid content in potato tubers of different cultivars
Rys. 1.Zawartość aminokwasów w bulwach ziemniaka rónych odmian
Rys. 2-11 na końcu art
Fig. 2-11 explonations end art.
THE EFFECT OF INHIBITORS ON THE AMINO ACID CONTENT ...
303
The high quantity of the amides, mentioned above, resulted in a brighter colour of the
processed products. It is in the agreement with ASHOOR and ZENT [1984]. Considerable
quantities of leucine, valine, alanine, lysine, arginine were observed. They amounted to
4-8% of the total quantity of amino acids, whereas the observed quantities of histidine,
methionine glycine were the lowest. According to the data provided by several
scientists, potato tubers also contain tryptophan, however, the present studies did not
detected it. As some researchers state [YANG et al. 1999], tyrosine determines pulp
spottiness in potato tubers. Referring to the data of our research, the quantity of tyrosine
in potato tubers of all cultivars was not high, i.e. about 2 g⋅kg-1 of dry matter (Fig. 1).
At certain storage periods, the applied inhibitors significantly limited the quantity
of amino acids in potato tubers of all the analyzed cultivars (Fig. 2-11). Before storage,
the quantity of amino acids in potato tubers of all cultivars was about 40% higher as
compared to the quantity after 5 months of storage. After 8 months of storage the
quantity of amino acids increased again. After 8 month of storage the quantity of
leucine in potato tubers of cultivars Nida, Vaiva and Vokë was equal or even greater to
the quantity before storage (Fig. 4-6).
The share of essential amino acids is about 38-45% of all amino acids. As the
component of proteins, essential amino acids make the proteins complete. Leucine and
valine are the essential amino acids that prevailed in potato tubers, whereas the detected
quantities of methionine and histidine were the lowest (Fig. 2-6). The alterable amino
acids, asparagine and glutamine prevailed (Fig. 7-11). The latter were one of the most
mobile during storage. Over the entire period of storage, the lowest change in quantities
of lysine and histidine was observed in potato tubers of cultivars Goda and Nida
respectively, whereas the lowest change in quantities of histidine and isoleucine was
observed in potato tubers of cv. Vaiva (Fig. 2, 4 and 5). Over the entire period of
storage, the lowest change in quantities of amino acids, i.e. glycine, alanine and
tyrosine, was observed in potato tubers of all cultivars (Fig. 7-11).
After 5 months of storage, potato tubers of the analyzed cultivars processed with
dill essential oil demonstrated a significantly lower quantity of amino acids (Fig. 2-11).
After 8 months of storage, potato tubers of cv. Nida processed with dill essential oil
showed significantly the greatest quantity of amino acids (Fig. 4 and 9). After 8 months
of storage, the greatest quantity of amino acids was demonstrated basically by potato
tubers of other cultivars processed with caraway essential oil (Fig. 2-11). Literature
contains no data regarding a direct influence of inhibitors on the quantity of amino
acids, however, it was probably their influence on the prolongation of the rest period of
potato tubers that resulted in such accumulation of amino acids in potato tubers.
According to BRIERLEY et al. [1996], variation in the quantity of amino acids in potato
tubers is related to their sprouting. Considerable increase in the quantity of amino acids
at the end of storage was observed precisely at the moment when potato tubers of
respective cultivars just started to sprout. Already sprouted potato tubers featured no
substantial quantity of amino acids maybe due to the fact that a some amino acids
passed to sprouts. Before the analysis of quantity of amino acids, sprouts were removed
from tubers.
Conclusions
1.
The greatest quantity of amino acids was observed before storage in potato tubers
of all cultivars.
H. Danilchenko et al.
304
2.
After 5 months of storage potato tubers of all cultivars showed the lowest
quantity of amino acids.
3.
After 8 months of storage potato tubers of the analyzed cultivars processed with
caraway essential oil or dill essential oil demonstrated the greatest quantity of
amino acids.
Literature
ASHOOR S.H., ZENT J.B. 1984. Maillard browning of common amino acid and sugars. J.
Food Science 49: 1206-1207.
BRIERLEY E.R., BONNER P.L.R., COBB A.H. 1996. Factors influencing the free amino acid
content of potato (Solanum tuberosum L) tubers during prolonged storage. J. Sci. Food
Agric. 70: 515-525.
CIEŚLIK E., PRAZNIK W. 1997. Effect of harvest on the amino acid content in potato
tubers. Polish J. of Food and Nutrition Sciences 1: 27-33.
EPPENDORFER W.H., EGGUM B.O. 1994. Effects of sulphur, nitrogen, phosphorus,
potassium, and water stress on dietary fiber fractions, starch, amino acids and on the
biological value of potato protein. Plant Foods for Human Nutrition: 45: 299-313.
LESZCZYŃSKI W. 2000. Jakość ziemniaka konsumpcyjnego. śywność 4(25): 5-27.
MIETLICKI L.W., OZIERECKOWSKA O.L., KORALEWA N.P. et al. 1984. Biochimija immuniteta, pokoja, starenja rastenji. Moskwa: 263 ss.
YANG J., POWERS J.R., BOYLSTON T.D., WELLER K.M. 1999. Sugars and Free Amino Acids
in Stored Russet Burbank potatoes Treated with CIPC and Alternative Sprout
Inhibitors. J. of Food Sci. 64: 592-596.
Key words:
amino acid, potato storage, potato tuber, sprout inhibition
Summary
The research was carried out in 2002-2006 at the Crop-Growing Product Storage
and Processing Laboratory, Department of Horticulture, Lithuanian University of
Agriculture Animal Husbandry Institute of Lithuanian Veterinary Academy.
15 amino acids were determined in the studied samples of potato tubers of 5
cultivars including 9 essential amino acids. Essential amino acids make up 38-45% of
all the amino acids. In potato tubers, the dominating amino acids were leucine and
valine, the lowest amount was of methionine and histidine. Dominating alterable amino
acids were glutamic and aspartic acids. The latter were one of the most mobile during
the storage period. During the whole period of storage, the lowest changes were
observed in the following: lysine in cv. Goda tubers, histidine in cv. Nida tubers,
methionine, histidine and isoleucine in potato tubers of the cv. Vaiva. Alterable amino
acids, i.e. glycine, alanine and tyrosine, during the whole period of storage changed the
least in the potato tubers of all cultivars. The decrease in the protein content during the
storage period causes the increase in the tyrosine content. Tyrosine is not desirable in
potato tubers due to the fact that it negatively affects the color of raw potato tubers.
THE EFFECT OF INHIBITORS ON THE AMINO ACID CONTENT ...
305
Under the increasing amount of tyrosine, potatoes darken faster. According to the data
of our research, the amount of tyrosine in potato tubers of all cultivars was not
significant. After carrying out the correlation analysis between the darkening of raw
potato tubers and the amount of tyrosine, a weak correlation was determined (r = -0.4).
WPŁYW INHIBITORÓW NA ZAWARTOŚĆ AMINOKWASÓW
W BULWACH PRZECHOWYWANYCH ZIEMNIAKÓW
Honorata Danilcenko, Rima Pranaitiene,
Zivile Taraseviciene, Egidijavenskutoniene
Litewski Uniwersytet Rolniczy, Kaunas, Litwa
Słowa kluczowe:
ziemniak, przechowywanie, inhibitory wzrostu, aminokwasy
Streszczenie
W warunkach klimatycznych Litwy ziemniaki przechowywane są zaleŜnie od
kierunku uŜytkowania, od października do czerwca włącznie. Zalecana wysoka
temperatura (około 8°C) przechowywania ziemniaków przeznaczonych do przetwórstwa spoŜywczego prowadzi do intensywnego kiełkowania. Od wielu lat badane są
środki przeciwko kiełkowaniu mniej szkodliwe lub pochodzenia naturalnego. Zawartość
aminokwasów w bulwach ziemniaków najczęściej zaleŜy od cech odmianowych,
warunków uprawy i przechowywania.
Celem badań było określenie wpływu inhibitorów wzrostu na zmiany ilościowe
aminokwasów w czasie magazynowania ziemniaków w ciągu 8 miesięcy. W badaniach
przechowalniczych przetestowano odmiany ziemniaków: Goda, Gloria, Nida, Vaiva i
Vokë.
Po 8 miesiącach przechowywania oznaczono w bulwach 15 aminokwasów,
w tym 9 niezbędnych. 33-50% sumy aminokwasów stanowiły kwas glutaminowy
i asparaginowy. Najmniej wykryto histydyny, metioniny, glicyny. Tyrozyna we wszystkich bulwach badanych odmian ziemniaków występowała w nieduŜych ilościach około 2 g⋅kg-1 suchej substancji. Spośród niezbędnych aminokwasów decydująco
większe ilości obserwowano leucyny i waliny, natomiast najmniejsze metioniny. Ilość
nie niezbędnych aminokwasów: glicyny, alaniny i tyrozyny przez cały okres przechowywania zmieniała się najmniej. Stwierdzono, Ŝe naturalne inhibitory wzrostu
pozytywnie wpływały na jakość przechowywanych bulw ziemniaka poprzez zmniejszenie ilości aminokwasów w ciągu 5 miesięcy przechowywania.
Stosowanie naturalnych, efektywnych środków ograniczających kiełkowanie jest
szansą na wyeliminowanie szkodliwych środków chemicznych stosowanych podczas
przechowywania.
Prof. dr Honorata Danilchenko
Studentu 11, LZUU
Kaunas - Akademija
LITHUANIA
e-mail: [email protected]
Fig. 2.
Changes in the quantity of essential amino acids in potato tubers of cv. Goda during storage
Rys. 2.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Goda podczas przechowywania
Fig. 3.
Changes in the quantity of essential amino acids in potato tubers of cv. Gloria during storage
Rys. 3.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Gloria podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 4.
Changes in the quantity of essential amino acids in potato tubers of cv. Nida during storage
Rys. 4.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Nida podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 5.
Changes in the quantity of essential amino acids in potato tubers of cv. Vaiva during storage
Rys. 5.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Vaiva podczas przechowywania
K
KM
KR
C
Fig. 6.
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Changes in the quantity of essential amino acids in potato tubers of cv. Vokë during storage
Rys. 6.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Vokë podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 7.
Changes in the quantity of essential amino acids in potato tubers of cv. Goda during storage
Rys. 7.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Goda podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 8.
Changes in the quantity of essential amino acids in potato tubers of cv. Gloria during storage
Rys. 8.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Gloria podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 9.
Changes in the quantity of essential amino acids in potato tubers of cv. Nida during storage
Rys. 9.Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Nida podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 10.
Rys. 10.
Changes in the quantity of essential amino acids in potato tubers of cv. Vaiva during storage
Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Vaiva podczas przechowywania
K
KM
KR
C
untreated; kontrola
tubers treated with essential oil of caraway seeds; bulwy traktowane olejkiem eterycznym z nasion kminku
tubers treated with essential oil of dill seeds; bulwy traktowane olejkiem eterycznym z nasion kopru
tubers treated with CIPC; bulwy traktowane CIPC
Fig. 11.
Rys. 11.
Changes in the quantity of essential amino acids in potato tubers of cv. Vokë during storage
Zmiany ilości niezbędnych aminokwasów w bulwach ziemniaka odmiany Vokë podczas przechowywania