超临界流体技术去除番茄红素油树脂中的有机溶剂残留研究

采用超临界CO2流体萃取技术,对番茄红素油树脂中的有机溶剂残留进行反向萃取.探讨了不同压力、温度、流量、时间对有机溶剂去除效率的影响,筛选出最佳去除条件:压力20 685.0 kPa,温度45 ℃,CO2流量2.0 L/min,提取时间4 h,溶剂最终去除率达89%.     

番茄红素β环化酶基因（Lyc-β）RNAi载体构建及表达鉴定

从番茄(Lycopersicun esculentum Mill)提取总RNA,根据GenBank中番茄红素β环化酶基因(Lye-β)序列(X86452),经mRNA反转录扩增出2段Lyc-β基因高度保守的300 bp DNA 片段,从β-葡萄糖苷酶基因(gusA)中扩增出170 bp的内含子片段.分别将两段不同的Lyc-β片段的正、反向序列与内含子连接,构建出两套干扰Lyc-β基因的植物表达载体.经根癌农杆菌(Agrobacterium tumefaciems)介导转化番茄,22 株转基因植株通过荧光定量PCR分析干扰效果,结果显示,2套干扰载体的干扰效率表现出一定的差异,Lyc-β基因mRNA平均含量分别为对照的11.78%和13.86%,进一步用HPLC分析转化株的番茄红素含量,结果表明,转基因植株中番茄红素的含量最高可达13.84 μg/g FW,是对照的4.26倍.     

无籽西瓜果实不同部位维生素C和番茄红素含量测定

为了研究西瓜不同部位维生素C、番茄红素含量,对6个红瓤和1个黄瓤无籽西瓜品种果实不同部位总维生素C(TAA)、还原型维生素C(AA)、氧化型维生素C(DHAA)和番茄红素含量进行测定,并检测红瓤无籽西瓜整瓜贮藏2个月后各成分损失率。结果表明,不同无籽西瓜品种之间果实TAA、AA和DHAA及番茄红素含量差异显著;果实不同部位TAA、AA和DHAA及番茄红素含量也有很大差异,中间部位均大于近皮部。TAA、DHAA和番茄红素含量相关性达到极显著水平,AA和DHAA含量相关性达到显著水平。室温下整瓜贮藏2个月后果实不同部位TAA、AA、DHAA和番茄红素含量损失率为20%～50%。     

Postharvest ultraviolet-C irradiation suppressed Psy 1 and Lcy-β expression and altered color phenotype in tomato (Solanum lycopersicum) fruit

Mature green cherry tomato fruit were harvested and treated with ultraviolet-C (UV-C) irradiation at a predetermined dose of 4.2 kJ m⁻², and stored at 18 °C for 35 days. The effects of UV-C treatment on color change, pigment contents, and the expression of major genes involved in carotenoid metabolism, including Psy 1, Pds, Lcy-β, and Lcy-ɛ, encoding phytoene synthase, phytoene desaturase, lycopene β-cyclase and lycopene ɛ-cyclase, respectively, were examined. The UV-C treated fruit developed a pink red color in contrast to the normal orange red color of control fruit. Lycopene accumulation during ripening in UV-C treated fruit was significantly inhibited but its final content was not affected. However, both accumulation and final content of β-carotene were significantly suppressed in UV-C treated fruit. The lower content of β-carotene, leading to a higher lycopene to β-carotene ratio, is probably responsible for the altered color phenotype in UV-C treated fruit. Psy 1, a major gene involved in lycopene synthesis was inhibited by UV-C irradiation. Significantly suppressed expression of Lcy-β gene was also observed in UV-C treated fruit. Thus it is possible that the lower transformation from lycopene to carotenes contributed to the relatively stable content of lycopene.