Citrus Research Institute , Southwest University , Chongqing 400712 , China.
Citrus Research and Education Center , University of Florida , Lake Alfred , 33850 Florida , United States.
J Agric Food Chem. 2020 Jan 29;68(4):1030-1037. doi: 10.1021/acs.jafc.9b06647. Epub 2020 Jan 21.
The off-flavor produced after thermal stabilization of mandarin (, Blanco) juices has limited the production of commercial juices. Methanethiol, a putrid-smelling sulfur volatile, has been identified for the first time in heated mandarin juices. Identification was achieved using a combination of capillary gas chromatography with two dissimilar columns and a dual sulfur-specific pulsed flame photometric detector and selected ion mass spectrometry detection. Static headspace solid-phase microextraction quantitation found that average odor activity values (OAVs) in heated juices were 25.5 for methanethiol compared to 10.8 for dimethyl sulfide. OAVs for methanethiol and dimethyl sulfide in fresh juices were ND (not detected) and 5.5, respectively. Hydrogen sulfide, carbonyl sulfide, carbon disulfide, and dimethyl disulfide were also identified and quantitated. Thermal decomposition studies of nonvolatile sulfur-containing potential precursors indicated that methionine was the major source of methanethiol. Additional heating studies with model juices demonstrated that ascorbic acid greatly accelerated the formation of methanethiol and methional, as well as dimethyl di and tri sulfides.
热处理后产生的杂味限制了商业果汁的生产。已首次在加热的橘子汁中鉴定出甲硫醇，这是一种有恶臭的硫挥发物。鉴定是通过使用两种不同柱的毛细管气相色谱法和双硫特定脉冲火焰光度检测器以及选择离子质谱检测法相结合实现的。静态顶空固相微萃取定量发现，与二甲基硫醚的 10.8 相比，加热果汁中甲硫醇的平均气味活度值（OAV）为 25.5。新鲜果汁中甲硫醇和二甲基硫醚的 OAV 分别为 ND（未检出）和 5.5。还鉴定和定量了硫化氢、羰基硫、二硫化碳和二甲基二硫。非挥发性含硫潜在前体的热分解研究表明蛋氨酸是甲硫醇的主要来源。与模型果汁的其他加热研究表明，抗坏血酸大大加速了甲硫醇和甲硫醛以及二甲基二硫和三硫的形成。
