Effects of lipase, lipoxygenase, peroxidase and free fatty acids on volatile compound found in boiled buckwheat noodles.
BACKGROUND
Relationships between buckwheat (Fagopyrum esculentum Moench) flour lipase, lipoxygenase and peroxidase activity, along with levels of individual free fatty acids (FFAs) and levels of headspace volatile compounds of boiled buckwheat noodles, were investigated for 12 different buckwheat varieties. Enzyme activities and FFA levels in flour were correlated with their respective varietal arrays of boiled noodle headspace volatile compounds, measured by gas chromatography-mass spectrometry.


RESULTS
The volatiles hexanal, tentative butanal, tentative 3-methylbutanal and tentative 2-methylbutanal showed significant positive correlation with one another, indicating that they may be generated through similar mechanisms. These important volatile components of buckwheat flavor were also positively correlated with lipase and/or peroxidase activity, indicating that enzymatic reactions are important in flavor generation in boiled buckwheat noodles. On the other hand, pentanal, which showed no significant correlation with any enzyme activity, showed a significant positive correlation to the levels of C18:2 and C18:3 FFAs, suggesting the existence of a 'non-enzymatic' and/or 'uncertain enzymatic pathway' for flavor generation in boiled buckwheat noodles.


CONCLUSIONS
Lipase and peroxidase in buckwheat flour are important for flavor generation of boiled buckwheat noodles. This information is important for increasing desirable flavor of buckwheat products as well as for selecting varieties with improved flavor.
Suzuki
Tatsuro
T
National Agricultural Research Center for Hokkaido Region, Shinsei, Memuro, Kasai-gun, Hokkaido 082-0081, Japan. tsuzu@affrc.go.jp
Kim
Sun-Ju
SJ
Mukasa
Yuji
Y
Morishita
Toshikazu
T
Noda
Takahiro
T
Takigawa
Shigenobu
S
Hashimoto
Naoto
N
Yamauchi
Hiroaki
H
Matsuura-Endo
Chie
C
D004798:Enzymes / Q000378:metabolism*; D019612:Fagopyrum / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005504:Food Analysis; D005838:Genotype; D008049:Lipase / Q000378:metabolism; D008084:Lipoxygenase / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D012639:Seeds / Q000235:genetics / Q000378:metabolism*; D012677:Sensation; D013649:Taste; D055549:Volatile Organic Compounds / Q000378:metabolism*
D004798:Enzymes; D005230:Fatty Acids, Nonesterified; D010940:Plant Proteins; D055549:Volatile Organic Compounds; D009195:Peroxidase; D008084:Lipoxygenase; D008049:Lipase