College of Food Engineering, Ludong University, Yantai 264025, China.
Department of Smart Farm Science, College of Life Sciences, Kyung Hee University, Yongin 17104, Korea.
Molecules. 2022 Jul 26;27(15):4782. doi: 10.3390/molecules27154782.
Although ginseng leaf is a good source of health-beneficial phytochemicals, such as polyphenols and ginsenosides, few studies have focused on the variation in compounds and bioactivities during leaf thermal processing. The efficiency of far-infrared irradiation (FIR) between 160 °C and 200 °C on the deglycosylation of bioactive compounds in ginseng leaves was analyzed. FIR treatment significantly increased the total polyphenol content (TPC) and kaempferol production from panasenoside conversion. The highest content or conversion ratio was observed at 180 °C (FIR-180). Major ginsenoside contents gradually decreased as the FIR temperature increased, while minor ginsenoside contents significantly increased. FIR exhibited high efficiency to produce dehydrated minor ginsenosides, of which F4, Rg6, Rh4, Rk3, Rk1, and Rg5 increased to their highest levels at FIR-190, by 278-, 149-, 176-, 275-, 64-, and 81-fold, respectively. Moreover, significantly increased antioxidant activities were also observed in FIR-treated leaves, particularly FIR-180, mainly due to the breakage of phenolic polymers to release antioxidants. These results suggest that FIR treatment is a rapid and efficient processing method for producing various health-beneficial bioactive compounds from ginseng leaves. After 30 min of treatment without leaf burning, FIR-190 was the optimum temperature for producing minor ginsenosides, whereas FIR-180 was the optimum temperature for producing polyphenols and kaempferol. In addition, the results suggested that the antioxidant benefits of ginseng leaves are mainly due to polyphenols rather than ginsenosides.
虽然人参叶是有益健康的植物化学物质的良好来源，如多酚和人参皂苷，但很少有研究关注叶类植物在热加工过程中化合物和生物活性的变化。分析了远红外辐射（FIR）在 160°C 至 200°C 之间对人参叶中生物活性化合物脱糖作用的效率。FIR 处理显著增加了总多酚含量（TPC）和从 panasenoside 转化而来的山奈酚产量。在 180°C（FIR-180）时观察到最高含量或转化率。随着 FIR 温度的升高，主要人参皂苷的含量逐渐降低，而次要人参皂苷的含量显著增加。FIR 对产生脱水的低聚糖具有高效率，其中 F4、Rg6、Rh4、Rk3、Rk1 和 Rg5 在 FIR-190 时分别增加到最高水平，分别为 278 倍、149 倍、176 倍、275 倍、64 倍和 81 倍。此外，在 FIR 处理的叶片中还观察到抗氧化活性显著增加，尤其是在 FIR-180 时，主要是由于酚类聚合物的断裂释放抗氧化剂。这些结果表明，FIR 处理是一种快速有效的方法，可以从人参叶中产生各种有益健康的生物活性化合物。在没有叶片燃烧的情况下处理 30 分钟后，FIR-190 是产生低聚糖的最佳温度，而 FIR-180 是产生多酚和山奈酚的最佳温度。此外，结果表明，人参叶的抗氧化益处主要归因于多酚而不是人参皂苷。
