Background Roses are flowers which contain various phytochemicals and have been used for food and medicinal purposes in many countries. Materials, including flowers, are available for limited periods when plants can be cultivated. Objective To evaluate the quality of rose petals on the basis of cultivars and drying methods, chromaticity, phytochemical contents, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Method Petals of three rose cultivars were dried by hot air drying (HD) and freeze drying (FD). Subsequently, the chromaticity and the contents of pigment, total flavonoids, and ascorbic acid, and DPPH radical scavenging activity were analyzed. Results The total color difference (△E)values of rose red (RR, Calypso) and rose orange (RO, Lambada) were low in FD. In contrast, in rose yellow (RY, Ileos), there was no significant difference in chromaticity regulation regardless of the drying methods. The pigment contents were generally increased by drying. The carotenoid content in the RR and anthocyanin and carotenoid contents in RO were higher in FD than in HD. The drying operations increased the flavonoid and ascorbic acid content and antioxidant activity in roses, but the difference between the drying methods was not significant. Correlation coefficient analysis revealed ascorbic acid and anthocyanin to have a high positive correlation (r = 0.843), followed by flavonoid and DPPH radical scavenging activity. Conclusions This study showed that the drying operations increased the flavonoid and ascorbic acid contents, and the chromaticity and pigment content of some cultivars was higher in FD. Highlights Comparison of the color change, phytochemical content, and antioxidant activity by the drying methods (FD and HD treatment) in the three rose cultivars with red, orange, and yellow petals showed the increased phytochemical contents and antioxidant activity after drying, and chromaticity and pigment content were more stable and higher in FD.

中文翻译：

---

干燥操作对玫瑰品种色素及植物化学性质的影响

背景玫瑰是含有多种植物化学物质的花卉，在许多国家已被用于食品和药用目的。包括花卉在内的材料在可以种植植物的有限时期内可用。目的从品种、干燥方法、色度、植物化学成分、2,2-二苯基-1-苦基肼（DPPH）自由基清除活性等方面评价玫瑰花瓣的品质。方法采用热风干燥法(HD)和冷冻干燥法(FD)对三个月季品种的花瓣进行干燥。随后，分析了色素、总黄酮、抗坏血酸的色度和含量，以及DPPH自由基清除活性。结果玫瑰红（RR，Calypso）和玫瑰橙（RO，Lambada）在FD中的总色差（△E）值较低。相比之下，在玫瑰黄色（RY，Ileos）中，无论干燥方法如何，色度调节都没有显着差异。颜料含量通常通过干燥增加。FD中RR中的类胡萝卜素含量和RO中的花青素和类胡萝卜素含量高于HD。干燥操作增加了玫瑰中的黄酮和抗坏血酸含量和抗氧化活性，但干燥方法之间的差异不显着。相关系数分析显示抗坏血酸和花青素具有高度正相关（r = 0.843），其次是黄酮和DPPH自由基清除活性。结论本研究表明干燥操作增加了黄酮类和抗坏血酸的含量，部分品种在FD中的色度和色素含量较高。亮点对比色变，