College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, People's Republic of China.
J Agric Food Chem. 2012 Sep 26;60(38):9642-8. doi: 10.1021/jf3026524. Epub 2012 Sep 17.
This study investigated the changes in sugars, organic acids, α-tocopherol, β-carotene, phenolic profiles, total phenolic content (TPC), and antioxidant capacity of jujube fruits after four drying treatments (sun-, oven-, microwave- and freeze-drying). Sugar, organic acid, phenolic compounds, α-tocopherol, and β-carotene were qualitatived and quantitatived by high-performance liquid chromatography. The TPC and antioxidant activity of jujube samples were evaluated using the Folin-Ciocalteau method and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, respectively. Freeze-drying resulted in jujubes with higher antioxidant activity and was also a good choice for the preparation of β-carotene from jujubes for the food industry. Microwave-dried jujubes had a higher content of protocatechuic acid, catechin, and epicatechin and maintained the same antioxidant capacity with the freeze-dried jujubes. The combination of microwave- and freeze-drying may be an efficient alternative with shorter processing time and, consequently, less impact on the nutritional value of the jujube.
本研究探讨了四种干燥处理（日晒、烘箱、微波和冷冻干燥）后枣果中糖、有机酸、α-生育酚、β-胡萝卜素、酚类物质、总酚含量（TPC）和抗氧化能力的变化。采用高效液相色谱法对糖、有机酸、酚类化合物、α-生育酚和β-胡萝卜素进行定性和定量分析。采用 Folin-Ciocalteau 法和 2,2'-偶氮-双（3-乙基苯并噻唑啉-6-磺酸）自由基清除活性分别评估枣样的 TPC 和抗氧化活性。冷冻干燥使枣具有更高的抗氧化活性，也是从枣中制备β-胡萝卜素用于食品工业的良好选择。微波干燥的枣中含有更高含量的原儿茶酸、儿茶素和表儿茶素，并且保持与冷冻干燥枣相同的抗氧化能力。微波和冷冻干燥的组合可能是一种高效的替代方法，具有更短的加工时间，因此对枣的营养价值的影响更小。
