Yettella Ramesh R, Min David B
Department of Food Science and Technology, The Ohio State University, Columbus, Ohio 43210, USA.
J Agric Food Chem. 2008 Nov 26;56(22):10887-92. doi: 10.1021/jf8006739.
The effects of 0, 0.3, 0.6, and 0.9 mM Trolox and ascorbic acid on the singlet oxygen oxidation of tryptophan and tyrosine containing 25 ppm of riboflavin were determined by measuring tryptophan and tyrosine concentration by high-performance liquid chromatography analysis. The samples were stored in the a 1000 lx light storage box for 4 h at 30 degrees C. As the concentration of Trolox and ascorbic acid increased, the degradation of tryptophan and tyrosine decreased significantly at p < 0.05. Trolox reduced tryptophan and tyrosine degradation by quenching both singlet oxygen and excited triplet riboflavin, whereas ascorbic acid quenched singlet oxygen only. The total singlet oxygen quenchings of Trolox in the presence of tryptophan and tyrosine were 1.55 x 10(7) and 1.32 x 10(7) M(-1) s(-1), respectively. The total singlet oxygen quenchings of ascorbic acid in the presence of tryptophan and tyrosine were 1.16 x 10(7) and 1.10 x 10(7) M(-1) s(-1), respectively. Trolox was more effective than ascorbic acid in preventing the degradation of tryptophan and tyrosine.
通过高效液相色谱分析测量色氨酸和酪氨酸的浓度，测定了0、0.3、0.6和0.9 mM生育三烯酚和抗坏血酸对含有25 ppm核黄素的色氨酸和酪氨酸单线态氧氧化的影响。将样品在30℃下于1000勒克斯光照储存箱中储存4小时。随着生育三烯酚和抗坏血酸浓度的增加，色氨酸和酪氨酸的降解在p<0.05时显著降低。生育三烯酚通过淬灭单线态氧和激发三线态核黄素来减少色氨酸和酪氨酸的降解，而抗坏血酸仅淬灭单线态氧。在色氨酸和酪氨酸存在下，生育三烯酚的总单线态氧淬灭率分别为1.55×10⁷和1.32×10⁷ M⁻¹ s⁻¹。在色氨酸和酪氨酸存在下，抗坏血酸的总单线态氧淬灭率分别为1.16×10⁷和1.10×10⁷ M⁻¹ s⁻¹。在防止色氨酸和酪氨酸降解方面，生育三烯酚比抗坏血酸更有效。
