欧李花色苷的分离及其鉴定

采用高效液相色谱与离子阱串联飞行时间检测器-质谱联用技术,分离鉴定欧李中的花色苷类化合物。结果表明：从欧李红色素中分离得到6种组分,分别为：矢车菊-3-葡萄糖苷、天竺葵-3-葡萄糖苷、矢车菊-3-鼠李糖葡萄糖苷、天竺葵-3-鼠李糖葡萄糖苷、矢车菊-3-乙酰基葡萄糖苷、天竺葵-3-乙酰基葡萄糖苷。其中,矢车菊-3-葡萄糖苷为主要花色苷,占欧李总花色苷含量的62.6%。因此,采用高效液相色谱-质谱联用技术可有效地分离分析欧李中花色苷类物质。     

青梅资源的研究与应用

我国是青梅的原产地,青梅在我国的栽培和利用历史悠久。文中对青梅的化学成分、生物活性作用的研究及在医药和食品等行业中的应用进行了综述,同时对青梅今后的利用途径和发展方向进行了探讨,使我国的青梅资源能得到更合理有效的利用。     

处理方式对西藏光核桃功能因子及其抗氧化活性的影响

以西藏光核桃为试材,研究超声、压差闪蒸和蒸汽热烫3种处理方式对其功能因子(多酚、黄酮、多糖、果胶)的影响。采用DPPH、ABTS和FRAP体系评价光核桃功能因子的抗氧化活性,运用线性拟合分析法揭示功能因子含量与抗氧化活性之间的关系。结果表明:超声处理使光核桃多酚、黄酮、多糖含量及其抗氧化活性降低,果胶含量及其抗氧化活性显著升高(P0.05);压差闪蒸处理有利于光核桃多糖、果胶含量及其抗氧化活性的提高,不利于多酚和黄酮的保留;蒸汽热烫处理使光核桃多酚、黄酮、多糖、果胶含量及其抗氧化活性显著提高(P0.05),最大程度保留了绿原酸、儿茶素和新绿原酸。其中,蒸汽热烫1min时光核桃多酚含量最高[(15.05±0.04)mg GAE/g DB],蒸汽热烫3min时光核桃黄酮、多糖、果胶含量均达到最高值[分别为(67.40±0.74)mg RE/g DB、(143.95±0.37)mg GE/g DB、(61.81±1.10)mg GalA/g AIR]。线性拟合分析(P0.05)发现,多酚、黄酮、多糖含量与DPPH自由基清除能力呈显著正相关(R2分别为0.756,0.991,0.820)。综合分析认为,蒸汽热烫处理适宜作为光核桃深加工的有效预处理方式。     

Development of an integrated pretreatment fractionation process for fermentable sugars and lignin: Application to almond (Prunus dulcis) shell

An environmentally friendly pretreatment process was developed to fractionate cellulose, hemicellulose and lignin from almond (Prunus dulcis) shells, consisting of hot water pretreatment (HWP) coupled with organic solvent (organosolv) pretreatment of water/ethanol (OWEP). This integrated pretreatment process proved more effective on the basis of yield of fermentable sugar and lignin separation compared with HWP alone, dilute acid pretreatment (DAP), ammonia pretreatment (AP), lime pretreatment LP, organosolv water/ethanol pretreatment (OWEP), and organosolv water/acetone pretreatment (OWAP). In the coupled hot water-organosolv process, hemicellulose sugars were recovered in the first residual liquid while varying amounts of cellulose was retained in the residual solid. The lignin fraction was obtained by simply adjusting the pH from the second liquid. The optimal two-stage process consisted of first HWP stage at 195 °C for 30 min, resulting in w_glucose = 95.4% glucose recovery yield and w_xylose = 92.2% xylose removal. The second organosolv OWEP stage was operated at 195 °C for 20 min, in ethanol in water mixtures of <phi>_ethanol = 50% and resulted in nearly w_glucose = 100% glucose recovery yield, w_xylose = 90% xylose and w_lignin = 61% lignin removal. After enzymatic hydrolysis, glucose yield was up to w_glucose = 95%, compared to 61% yield from untreated almond. Images obtained via scanning electron microscopy (SEM) highlighted the differences in almond structure from the varying pretreatment methods during biomass fractionation.     

蒙古扁桃种仁油抗氧化性研究

采用ISO 6885:1998推荐的茴香胺值法、共轭烯烃值法和3种不同的自由基清除法对蒙古扁桃种仁油抗氧化性进行研究。结果表明:在4℃密封避光存放390 d之内,蒙古扁桃种仁油的茴香胺值维持在较低水平,其日均增量为0.03,具有较长的劣变质诱导期;在常温储存15月期间,蒙古扁桃种仁油共轭二烯含量明显增加,但共轭三烯含量甚微,高温处理导致蒙古扁桃种仁油的深度氧化,其共轭三烯含量增加,且随着储存时间的延长,发生深度氧化程度越大;蒙古扁桃种仁油对超氧阴离子自由基、羟自由基和DPPH自由基均具有较强的清除能力。     

青梅花、枝、叶中多酚的抗氧化活性及稳定性的研究

以我国特有的青梅品种"大叶青"为原料,测定了青梅花、枝、叶3种提取物(PF,PB,PL)中总酚含量,采用化学发光法、DPPH.,ABTS+.等评价自由基清除能力,采用铁离子还原法(FRAP)来评价还原力,分析了提取物中多酚含量与其活性的相关性,研究了青梅不同提取物的热稳定性。结果表明:青梅花、枝、叶等3种提取物富含多酚物质,在不同的评价体系中青梅提取物的抗氧化能力也不同,在清除O2-.、DPPH.、ABTS+.等自由基能力时青梅枝(PB)提取物的清除能力最强,而青梅花(PF)提取物的还原能力最强,相关性分析表明,自由基清除能力与总酚含量呈正相关(P<0.05)。3种提取物中以青梅叶提取物(PL)的热稳定性最强。