Content of amino acids and the quality of protein in Brussels sprouts,both raw and prepared for consumption

The aim of the investigation was to evaluate the content of amino acids and the quality of protein in Brussels sprouts. The investigation included the raw material, cooked sample and two types of frozen product stored at ?20 °C for 12 months and then prepared for consumption. The frozen products investigated were obtained using the traditional method (blanching before freezing) and the modified method (cooking before freezing, then defrosting and heating in microwave oven after refrigerated storage) of the ready-to-eat type. Brussels sprouts, both fresh and prepared for consumption, were a good source of protein and amino acids. Proline and glutamic acid were dominating; leucine and tyrosine with phenylalanine were limiting amino acids. The product obtained by modified method contained 16% less amino acids in 16 g N than the raw material and 14% less than the raw material after cooking, and also 10% lower than that of the traditionally obtained product.     

QuEChERS-高效液相色谱法测定苹果中多菌灵和噻菌灵

目的以固相萃取(solid phase extraction, SPE)、QuEChERS作为前处理方法,采用高效液相色谱检测苹果中多菌灵和噻菌灵。方法样品加乙腈、MgSO4、无水NaCl、NaAc提取,离心,取上清液加PSA净化,离心,取2 mL上清液用氮气吹干,用1.0 mL流动相溶解后,经高效液相色谱测定,外标法定量。结果多菌灵和噻菌灵在0.5～10μg/mL范围内线性关系良好,线性相关系数(r2)均大于0.9999,在0.50、2.0和10μg/mL3个添加水平下,加标回收率为84.15%～99.28%,相对标准偏差(relativestandarddeviations,RSDs)为1.69%～3.40%(n=6),检出限小于0.1 mg/kg。结论与SPE法相比, QuEChERS法具有更低的检出限、操作简单快速,适用于苹果中多菌灵和噻菌灵的检测。