Gregory Matthew J, Menary Robert C, Davies Noel W
School of Agricultural Science, Tasmanian Institute of Agricultural Research, and Central Science Laboratory, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
J Agric Food Chem. 2005 Jul 27;53(15):5969-75. doi: 10.1021/jf047989j.
Safranal is the compound most responsible for the aroma of saffron spice and is, together with the suite of crocin pigments, the major determinant of the product quality. The content of safranal and pigments in saffron is determined by the method of postharvest treatment of the Crocus stigmas. A range of drying treatments involving different temperatures, with or without air flow, was applied to stigmas from three harvest dates. Dual solvent extractions combined with quantitative measurement using GC and HPLC-UV-vis techniques were used to analyze the secondary metabolite contents of the products. It was demonstrated that these methods overcame the previously reported problems in measuring the concentration of both pigments and safranal in saffron caused by the very different polarities and thus solubilities of these compounds. The results showed that a brief (20 min) initial period at a relatively high temperature (between 80 and 92 degrees C) followed by continued drying at a lower temperature (43 degrees C) produced saffron with a safranal content up to 25 times that of saffron dried only at lower temperatures. Evidence was provided suggesting that drying with significant air flow reduced the safranal concentration. The results, moreover, indicated that high-temperature treatment had allowed greater retention of crocin pigments than in saffron dried at intermediate temperatures (46-58 degrees C). The biochemical implications of the various treatments are discussed in relation to the potential for optimizing color and fragrance quality in the product.
藏红花醛是藏红花香料香气的主要成分，与一系列藏花素色素一起，是产品质量的主要决定因素。藏红花中藏红花醛和色素的含量取决于藏红花柱头的采后处理方法。对三个收获日期的柱头进行了一系列不同温度、有无气流的干燥处理。采用双溶剂萃取结合气相色谱（GC）和高效液相色谱-紫外可见光谱（HPLC-UV-vis）技术进行定量测定，分析产品的次生代谢产物含量。结果表明，这些方法克服了先前报道的由于藏红花醛和色素极性差异极大因而溶解度不同，导致难以测量藏红花中这两种成分浓度的问题。结果显示，先在相对较高温度（80至92摄氏度之间）下短暂干燥（20分钟），然后在较低温度（43摄氏度）下继续干燥，所得到的藏红花的藏红花醛含量比仅在低温下干燥的藏红花高出25倍。有证据表明，有显著气流的干燥会降低藏红花醛浓度。此外，结果还表明，高温处理比在中等温度（46至58摄氏度）下干燥的藏红花能更好地保留藏花素色素。本文结合优化产品颜色和香气质量的潜力，讨论了各种处理方法的生化意义。
