超声波法提取塔罗科血橙皮黄酮类化合物工艺的优化

以塔罗科血橙(Citrus sinensis cv.Tarocco)皮为原料,采用超声波法提取黄酮类化合物。在单因素试验的基础上进行正交试验考察乙醇溶液体积分数、料液比、超声波处理时间、提取温度等因素对黄酮类化合物提取率的影响。结果表明,正交试验各因素对血橙皮黄酮类化合物提取率的影响从大到小依次为料液比、提取温度、乙醇溶液体积分数、超声波处理时间。最佳提取条件为乙醇溶液体积分数50%、超声波提取温度50℃、超声波处理时间40 min、料液比m橙皮粉∶V乙醇=1∶35 g/mL、超声波功率400 W,此条件下黄酮类化合物的提取率可达1.021 3%。

香榧假种皮提取物对潜叶跳甲的杀虫活性初步研究

为研究香榧(Torreya grandis cv.Merrilli)假种皮的杀虫活性,采用液-液萃取分离法对香榧假种皮乙醇提取浸膏进行萃取分离(石油醚、氯仿、乙酸乙酯、正丁醇),并采用水蒸气蒸馏法提取挥发油,采用叶碟浸渍法分别测定5种提取物对潜叶跳甲(Argopistes tsekooni)的杀虫活性。结果表明,5种处理液均有较好的杀虫活性,且浓度越高杀虫活性越强。石油醚提取物的杀虫活性最好,浓度达到200 mg/mL以上时处理96 h的校正死亡率达到100%,其次为氯仿提取物。毒力测定结果表明,石油醚提取物LD50最小,为32.82 mg/mL。因此,香榧假种皮提取物表现出较好的抑虫活性,具有进一步研究开发的价值。

Alteration of pectin metabolism in blood orange fruit(Citrus sinensis cv.Tarocco)in response to vesicle collapse

Segment drying is a severe physiological disorder of citrus fruit,and vesicles become granulated or collapsed.Aside from the hypothesis that alteration of cell wall metabolism is the main factor of citrus granulation,little is known about vesicle collapse.This study aimed to elucidate the changes in pectin metabolism during vesicle collapse in blood orange.Vesicle collapse was characterized by decreased nutrients and increased chelate-and sodium carbonate-soluble pectin and calcium content.The nanostructure of chelate-soluble pectin became complex and developed multi-branching upon collapse.The activity of pectin methylesterase increased,while that of polygalacturonase and pectate lyase decreased upon collapse.Genome-wide transcriptional analysis revealed an increasing pattern of genes encoding pectin methylesterase and other enzymes involved in pectin synthesis and demethylesterification upon collapse.Drying vesicles were characterized by increased abscisic acid content and relevant gene expression.In conclusion,we discovered alteration in pectin metabolism underlying citrus vesicle collapse,mainly promoting pectin demethylesterification,remodeling pectin structures,and further inhibiting pectin degradation,which was hypothesized to be a main factor for citrus collapse.This is the first study to disclose the potential intrinsic mechanism underlying vesicle collapse in orange fruit.