College of Food Science and Nutritional Engineering, China Agricultural University; National Engineering Research Center for Fruit & Vegetable Processing; Key Laboratory of Fruit & Vegetable Processing, Ministry of Agriculture and Rural Affairs; Beijing Key Laboratory for Food Non-thermal Processing, Beijing 100083, China.
Beijing Academy of Food Sciences, Beijing 100068, China.
Food Chem. 2021 May 1;343:128459. doi: 10.1016/j.foodchem.2020.128459. Epub 2020 Oct 23.
Volatile sulfur compounds, such as dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide, cause the off-flavor in heat-sterilized juices and limit the commercial production of juices. In this study, we investigated the precursors for these volatile sulfur compounds and analyzed the potential inhibition methods. Upon separation of melon juice components using resin column, the dimethyl sulfide precursor was present in the acidic fraction whereas the dimethyl trisulfide precursor was present in neutral and acidic fractions. Exogenous addition experiments indicated S-methyl methionine was the precursor of dimethyl sulfide, and methionine was the precursor of dimethyl disulfide and dimethyl trisulfide. The release of volatile sulfur compounds was reduced by decreasing the pH to 2.0, or by adding epicatechin. We concluded S-methyl methionine and methionine were degraded into volatile sulfur compounds through nucleophilic substitution and Strecker degradation. This study can help establishing protocols for controlling the release of volatile sulfur compounds in heat-sterilized juices.
挥发性硫化合物，如二甲硫、二甲基二硫和二甲基三硫，会导致热杀菌果汁产生异味，并限制果汁的商业生产。在这项研究中，我们调查了这些挥发性硫化合物的前体，并分析了潜在的抑制方法。通过使用树脂柱分离甜瓜汁成分，发现二甲硫前体存在于酸性部分，而二甲基三硫前体存在于中性和酸性部分。外源添加实验表明 S-甲基蛋氨酸是二甲硫的前体，蛋氨酸是二甲基二硫和二甲基三硫的前体。通过将 pH 值降低到 2.0 或添加表儿茶素，可减少挥发性硫化合物的释放。我们得出结论，S-甲基蛋氨酸和蛋氨酸通过亲核取代和斯特雷克降解转化为挥发性硫化合物。本研究可为控制热杀菌果汁中挥发性硫化合物的释放建立规程提供帮助。
