Abschlussbericht Projekt: „Verminderung der ... - BLE

sieve with a porosity of >100 µm (tissue starch-free ) and dried in a compartment dryer (MMM-
Group, type Ecocell, Germany) at 40°C for 12 hours (tissue starch-free dry ). Results expressed
the cell wall material solids lager than 100 µm calculated from following equation (2):
⎛ tissue *
*100 ⎞
−1
deg reased
tissuestarch−
free⋅dry
dry cell wall material ( g kg FM ) = ⎜
⎟*
1000 (2)
*
⎝ tissuestarch−
free
tissue
fresh ⎠
The pectin concentration of the cell wall material and its degree or esterification were analysed
using the Cu 2+ ion exchange method. Thereby filtrates of total pectin (filtrate A) and
filtrates of the esterified pectin (filtrate B) were performed as described in detail in some
evidences (Pardede 2004; Braun 1989; Längerer et al. 1978; Bäuerle et al. 1977; Tibensky
et al. 1963) from 0.1 g dry cell wall material. Later we used a solution of 0.5 %
C 14 H 22 N 4 O 2 to change the Cu 2+ ions of the pectin filtrates against H + ions. Depending on
the amount of Cu 2+ the C 14 H 22 N 4 O 2 solution became blue coloured, whereby its absorbance
was measured at 560 nm with an UV-Vis spectral system (HP 8453, Germany).
CuSO 4 *5H 2 O standard solutions with a Cu 2+ concentration from 0.5 to 5 mg L -1 were used
to quantify the Cu 2+ concentration of the filtrates. Results reflecting the concentration and
the degree of esterification of pectin in potato tuber tissue were calculated with following
equations (3) and (4):
−1
−1 ⎡⎛
190 B − 14 A ⎞ ⎤ ⎛ dry cell wall material ( g kg FM ) ⎞
pectin ( g kg FM ) = ⎢⎜
⎟ * 1000 * 5⎥
*
⎜
⎟ (3)
⎣⎝
317 .5 * 1000 * W ⎠ ⎦ ⎝
1000
⎠
(% ) [( B − A)
*100] B
esterifica tion = /
(4)
A = total pectin concentration of filtrate A
B = esterified pectin of filtrate B
W = amount of the analysed dry cell wall material
The non-pectin components presented in the fresh matter of potato tuber tissue were calculated
as the difference between the dry cell wall material (2) and the pectin concentration
(3).
The concentration of other (cytoplasmatic) components in the fresh matter of potato tuber
tissue is figured as the differences between the dry matter concentration and the summarized
concentration of the starch and the dry cell wall material.
Statistics. The obtained data were analysed with Sigma Stat statistical program (STAT32).
All data sets were tested for normal distribution and variance homogeneity (p= 0.05). Following
analyses of variance were calculated for cultivar and specific gravity. Calculated
means were compared by Tukey-test (p ≤0.05). Correlation and multiple regression procedures
between normally distributed quality parameters were performed using Pearson correlation
coefficients.
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