By headspace solid-phase microextraction/gas chromatography-mass spectrometry, the effects of 1% (w/v) alcohol denatured soybean protein isolates (L-SPI), native soybean protein isolates (N-SPI), as well as the thermal denaturation of soybean protein isolates (H-SPI) on low concentration (24 μmol/L) of citral was studied in aqueous. The results shows that the SPI could catalyze citral isomerization and yield methyl heptenone and acetaldehyde by inverse aldol condensation degradation. 3-Hydroxycitronelloal was formed as an intermediate in this reaction. The catalytic efficiency of the L-SPI was higher than that of N-SPI, whereas the catalytic efficiency of H-SPI was the lowest. Additionally, it shows that the catalytic efficiency increased as the pH increased. The catalytic efficiency of 7S (Soybean β-Conglycinin) was greater than that of 11S (Soy bean Proglycinin).

中文翻译：

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大豆分离蛋白与柠檬香精相互作用机理研究：柠檬醛的异构化和降解。

通过顶空固相微萃取/气相色谱-质谱法，研究 1% (w/v) 乙醇变性大豆分离蛋白 (L-SPI)、天然大豆分离蛋白 (N-SPI) 以及热变性的影响研究了大豆分离蛋白 (H-SPI) 在水溶液中对低浓度 (24 μmol/L) 柠檬醛的影响。结果表明，SPI可以催化柠檬醛异构化，通过逆羟醛缩合降解生成甲基庚烯酮和乙醛。3-羟基香茅醛作为该反应的中间体形成。L-SPI的催化效率高于N-SPI，而H-SPI的催化效率最低。此外，它表明催化效率随着pH值的增加而增加。7S（大豆β-伴大豆球蛋白）的催化效率高于11S（大豆原大豆球蛋白）。