Generation of free amino acids and gamma-aminobutyric acid in water-soaked soybean by high-hydrostatic pressure processing.
The effects of high-hydrostatic pressure processing (HPP) on soybean cotyledon as a cellular biological material were investigated from the viewpoints of the cell structure and enzyme reaction system. Damage to cell structure was evaluated by measuring dielectric properties using the Cole-Cole arc, the radius of which decreased as pressure level increased. Results suggested that cell structure was damaged by HPP. The distribution of free amino acids was measured after HPP (200 MPa) of soybean soaked in water or sodium glutamate (Glu) solution. HPP resulted in high accumulation of free amino acids in water-soaked soybean, due to proteolysis. HPP of soybean in Glu solution caused higher accumulation of gamma-aminobutyric acid, suggesting that both proteolysis and specific Glu metabolism were accelerated by HPP. We concluded that HPP partially degraded cell structure and accelerated biochemical reactions by allowing enzyme activities to remain. These events can be considered "high-pressure induced transformation" of soybean.
Ueno
Shigeaki
S
Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. shigeakiu@bios.tohoku.ac.jp
Shigematsu
Toru
T
Watanabe
Takae
T
Nakajima
Kanako
K
Murakami
Mina
M
Hayashi
Mayumi
M
Fujii
Tomoyuki
T
D000596:Amino Acids / Q000032:analysis*; D005511:Food Handling / Q000379:methods*; D006874:Hydrostatic Pressure; D010936:Plant Extracts / Q000032:analysis*; D013025:Glycine max / Q000737:chemistry*; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D000596:Amino Acids; D010936:Plant Extracts; D005680:gamma-Aminobutyric Acid