Abschlussbericht Projekt: „Verminderung der ... - BLE

FERRIC REDUCING - ANTIOXIDANT POWER OF POTATO TUBERS (SOLANUM TUBEROSUM)
OF VARIOUS CULTIVARS DIFFERING IN THEIR BLACKSPOT SUSCEPTIBILITY
Department of Crop Sciences, Section Quality of Plant Products
Wulkow A 1 , Pawelzik E, Keutgen AJ and Ernst H
Section Quality of Plant Products, Department of Crop Sciences, Georg- August University Göttingen, Carl- Sprengel -Weg 1, 37075 Germany, 1 email: awulkow@gwdg.de
Introduction
Blackspot is an inherent vice, which impair the tuber quality. The discoloration of potato flesh develops as a result of mechanical
impact on the tubers through enzymatic reactions, where oxygen is involved. The damaged tissue survives as cell union or it may
be destructed. A linked influx of molecular oxygen enables the formation of activated oxygen species which may reduce Fe (III).
The aim of the present study is to determine the ferric reducing-antioxidant power of tubers of eight potato varieties differing in their
blackspot susceptibility.
Material & Methods
plant material: 1. tubers of different varieties: Afra, Adretta, Granola, Renate, Gala, Nicola, Marabel, Lolita
2. tuber size 40 – 50 mm
3. tubers divided in classes of specific gravity from 1.095 kg L -1 in 0.01 increments
cultivation: April - September 2005 & 2006, humus & sandy soil (hS)
storage: cold storage (4°C, 95 % RH) for five (5) & eight (8) months
analyses: the ferric reducing- antioxidant power (FRAP) based on the reduction of the ferric tripyridyltriazin (Fe (III)- TPTZ)
complex to the ferrous tripyridyltriazin (Fe (II)- TZPZ) measured at 595 nm
Results & Discussion
FRAP (mmol Fe (II) kg -1 FM) BSI (%)
FRAP (mmol Fe (II) kg -1 FM) BSI (%)
100
80
60
40
20
4
1.5
0
100
80
60
40
20
3
1.5
0
D
B
A A
A
C C C
D D D
a
b
a
a a a
b
a
b b b c
< 1.065 < 1.075 < 1.085 < 1.095
specific gravity (kg L -1 )
FRAP (harvest)
BSI (harvest)
D
D
C
b b a a
a b ab
E
FRAP (5)
BSI (5)
C
D
FRAP (8)
BSI (8)
< 1.055 < 1.065 < 1.075 < 1.085 < 1.095 > 1.095
a
B
a
B
C
ab
a
A
A
B
b
bc
a. b. c - different letters indicate significant differences of FRAP values (p