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Effect of pro‐oxidants on the occurrence of 2‐pentyl pyridine in soy protein isolate
Author(s) -
Boatright W. L.,
Crum A. D.,
Lei Q.
Publication year - 1998
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-998-0186-5
Subject(s) - pyridine , soy protein , chemistry , food science , ultraviolet , ultraviolet light , hexane , lipoxygenase , enzyme , biochemistry , chromatography , organic chemistry , photochemistry , materials science , optoelectronics
Levels of 2‐pentyl pyridine in hexane‐defatted soybean flours prepared from Burlison, Stressland, and Probst varieties and a variety null for lipoxygenase 1, 2, and 3 were determined using an internal standard of deuterium‐labeled 2‐pentyl pyridine. These defatted flours contained from 0.06 to 0.51 ppm 2‐pentyl pyridine. The flours from lipoxygenase‐null and Stressland varieties of soybeans contained the lowest levels. Control freeze‐dried soy protein isolates (SPI) prepared from defatted‐flours all contained from 0.16 to 0.18 ppm 2‐pentyl pyridine. Adding pro‐oxidants (FeCl 3 , CuCl 2 ) or exposing the protein slurries to ultraviolet light during SPI processing increased the level of 2‐pentyl pyridine in the protein isolates by up to 1256 percent above the control Burlison, Stressland, and Probst SPI. The CuCl 2 and/or UV treatment contributed the largest increase in each case. The same pro‐oxidant and UV treatments contributed no significant increases in the level of 2‐pentyl pyridine in the protein isolates from the lipoxygenase null SPI.