Joint International Conference on Long-term Experiments ...

The reliability of the method was checked with recovery experiments with L- Tryptophan
(Fluka, Germany), and by the analysis of reference sample with known tryptophan
content.
MATERIALS AND METHODS
Pea samples from the control (0+0+0 kg/ha) and the 20 th treatment of the 1995 OTK
research were analysed from Putnok, Mosonmagyaróvár, Keszthely, Bicsérd,
Hajdúböszörmény and Iregszemcse research sites. Crude protein content of the analysed
samples varied from 6 to 23 %, according to the research site.
Hydrolysis: For hydrolysis 8,40 g Ba(OH)2x8H2O and 10 ml distilled water was added to
the sample that contained some 10 mg Nitrogen in a pressure-resistant test tube with
Teflon pipe. The reaction was performed at 110° C for 20 hours. The mixture was
washed to a flask with 30 ml distilled water, and Barium was precipitated with 0,05 M
Phosphoric acid in the form of Barium phosphate. The pH of the filtrate was adjusted to
3,0 with 6N Hydrochloric-acid and diluted to 100 ml with distilled water : methanol
80:20 solvent mixture. The solution was filtered through 0,45 µm membrane filter
(Millipore, USA) before HPLC analysis.
Chromatography: High performance liquid chromatography was performed by a
Merck-Hitachi AS 4000A equipment. Gradient program was used for separation on C18
column (LiChorCart 125x4) with eluent A:0,01mol/l KH2PO4 (Reanal) /Metanol 95:5 and
B: Methanol (Merck). For detection Merck-Hitachi F1050 fluorescent detector was used
(ex: 280 nm, em: 356 nm).
RESULTS AND DISCUSSIONS
According to the literature, the protein content of feed peas is highly dependent on the
crop year and the cropping site (Figure 1). Data show that the protein content of the
control plots varied from 19 to 25 % (Mosonmagyaróvár and Iregszemcse). The
fertilization did not increase the protein content of pees in Putnok, at the same time, it
decreased in Keszthely. More (in Mosonmagyaróvár from 19.59 to 23.63%) or less (in
Hajdúböszörmény from 23.4 to 24.93%)increase was found in the other research sites.
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