Variation of 1-kestose, nystose and higher fructooligosaccharides in burdock root stored under different temperature regimes.

The variation of fructooligosccharides (FOSs) of differed degree of polymerization (DP), 1kestose, nystose, GF4, GF5, GF6, GF7 and GF8 in burdock roots stored during 42 days under three different temperature regimes, 0, 15 and 20 °C was investigated. Results showed that 1kestose increased more significantly at 0 and 15 °C, and nystose showed similar variation but the increase observed at 0 °C was higher than those observed at 15 and 20 °C. The fructosylnystose (GF4) increased significantly during the first three days of storage but slightly and progressively during the four following weeks, and the GF5 and GF6 showed close pattern under the three different storage temperatures. The higher oligomer GF7 showed similar variation to these of GF6 but the increase during the first four weeks of storage was lower at 0 °C. At 0 °C, GF8 showed similar variation to those of GF5, GF6 and GF7, but at 15 and 20 °C, GF8 increased after three days and remained quite stable during three weeks but increased at 20 °C during the last two weeks. Overall, results showed that the different FOS increased significantly during the first four weeks at 15 and 20 °C and then decreased, while this decrease was not observed at 0 °C.