Food Science and Technology Programme, Department of Chemistry, National University of Singapore , 117543 Singapore.
J Agric Food Chem. 2014 Jun 11;62(23):5296-304. doi: 10.1021/jf500739n. Epub 2014 Jun 2.
There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule. H2S from organic polysulfides, in particular, is increasingly gaining attention for their beneficial effects to cardiovascular health. Here, we studied shallot as a potential dietary source of organic polysulfides and examined the effects of processing conditions on its polysulfide profiles. Boiling, autoclaving, and freeze-drying were tested on whole and crushed shallot bulbs, analyzing their effect on the yield of organosulfides. Seventeen organosulfides, including disulfides, trisulfides, and cyclic polysulfides, were identified. Significant differences in the quantitative and qualitative profiles of organosulfides in the hydrodistilled and solvent extracted oils were observed. Freeze-drying retained the majority of the organosulfides, but the whole-autoclaved and whole-boiled shallots lost more than 95% of their organic polysulfides. Crushed-boiled and crushed-autoclaved shallot lost 76-80% of their organosulfides, likely due to the thermal sensitivity of these compounds. The organosulfide profiles are sensitive to the pH values of the processing media. In general, disulfides increased at basic pH (pH 9.0) while trisulfides and cyclic organosulfides are much higher at the acidic to neutral pH values (pH 3.0-5.0). Our results provide important information on the effects of processing conditions that are relevant for optimizing extraction of organosulfides from shallot for further studies evaluating their H2S-releasing activity.
越来越多的证据表明 H2S 作为内源性细胞信号分子对健康有益。特别是有机多硫化物中的 H2S，因其对心血管健康的有益作用而受到越来越多的关注。在这里，我们研究了洋葱作为有机多硫化物的潜在膳食来源，并研究了加工条件对其多硫化物谱的影响。我们测试了整洋葱和碎洋葱在煮沸、高压灭菌和冻干条件下的处理效果，分析了它们对有机硫化物产率的影响。共鉴定出 17 种有机硫化物，包括二硫化物、三硫化物和环状多硫化物。在水蒸馏和溶剂提取油中观察到有机硫化物的定量和定性谱存在显著差异。冻干保留了大部分有机硫化物，但整洋葱高压灭菌和整洋葱煮沸损失了超过 95%的有机多硫化物。碎洋葱煮沸和碎洋葱高压灭菌损失了 76-80%的有机硫化物，这可能是由于这些化合物的热敏感性。有机硫化物谱对加工介质的 pH 值敏感。一般来说，二硫化物在碱性 pH（pH 9.0）下增加，而三硫化物和环状有机硫化物在酸性到中性 pH 值（pH 3.0-5.0）下更高。我们的结果为优化从洋葱中提取有机硫化物以进一步研究其 H2S 释放活性的加工条件提供了重要信息。
