云南小粒咖啡花多糖提取工艺优化及其抗氧化活性分析

本文旨在优化咖啡花多糖(ACP)的提取工艺,并评价其抗氧化活性。以咖啡花多糖得率为评价指标,通过对超声温度、超声时间、液料比、超声功率、浸泡时间和醇沉浓度6个工艺条件对咖啡花多糖得率影响的考察,选取了影响较大的超声温度、超声时间和超声功率3个工艺条件进行响应面分析。再通过DPPH、ABTS+自由基清除实验和FRAP法评估其抗氧化能力。结果表明,超声提取咖啡花多糖的最佳工艺条件为超声温度69.5℃,超声时间93 min,超声功率175 W,液料比10:1 mL/g,浸泡时间30 min,乙醇浓度80%,该条件下多糖得率为2.292%。结果表明,咖啡花多糖的DPPH自由基清除能力IC_(50)值为3.844 mg·mL^(−1);以Trolox当量来表示其ABTS+自由基清除能力为0.921 mmol Trolox/g ACP;以Fe^(2+)当量来表示其还原能力为0.0565 mmol Fe^(2+)/g ACP,咖啡花多糖具有一定的抗氧化活性。本研究将为咖啡副产品的综合利用与开发提供一定的参考理论依据。

咖啡花中高氯酸盐含量超高效液相色谱-串联质谱测定法的不确定度评价

目的采用超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLCMS/MS)测定咖啡花样品中高氯酸盐含量,并对检测过程进行不确定度评价。方法依据JJF 1059.1—2012《测量不确定度评定与表示》,分析并计算检测过程中的各项不确定度分量,最后合成得到超高效液相色谱-串联质谱法测定咖啡花中高氯酸盐含量的扩展不确定度。结果在本实验中,咖啡花样品中高氯酸盐的含量为(0.1313±0.0122)mg/kg,k=2,相对标准偏差为2.39%。结论超高效液相色谱-串联质谱法测定咖啡花样品中高氯酸盐含量过程中不确定度的主要来源为配制标准系列过程中吸取同位素内标的移液器、配制标准系列过程中使用的玻璃量器及移液器和标准系列测定及拟合过程。

一种注射式咖啡拉花机的结构与原理

本团队受3D打印机启发,研制了注射式咖啡拉花机,以巧克力酱为拉花原料,实现了全自动任意图案的咖啡拉花。该产品是机械自动化在咖啡拉花上的应用,代替人工咖啡拉花。其机械结构原理简单、控制结构容易实现,生产简单,整体设备成本低,拉花效率高并且误差小,人为操作简单,性价比高。

Cultivation of Perennial Herbaceous Legumes in Weed Management in Coffee Plantation on the Cerrado

The aim of this study was to evaluate the cultivation of perennial herbaceous legumes on weed control and yield of the coffee crop in the Cerrado. The experimental design was a randomized complete block with four replications. The 10 treatments tested in factorial 4 × 2 ＋ 2, were four legumes： forage peanut （Arachis pintoi）, hybrid Java （Macrotyloma axillare）, perennial soybean （Neonotonia wightii） and wild ground nut （Calopogonium mucunoides）; two forms in the interrows of coffee plants with two and three rows of legumes spaced by 0.50 m and 0.25 m, respectively; and two additional treatments consisted of hand weeding with hoe and chemical control with glyphosate. The hybrid Java and wild ground nut in the first year and the hybrid Java and perennial soybean in the second year, all followed by forage peanut, promoted lower density and biomass of the weeds. The wild ground nut in the first year and forage peanut in the second year showed higher soil cover. The hybrid Java had its highest biomass production in two years, and wild ground nut being higher in the first year. The cultivation of perennial herbaceous legumes promoted weed control without interfering in the productivity of the coffee crop.

Identification of Quantitative Trait Loci （QTLs） Determining Flowering in the Robusta Coffee （Coffea canephora Pierre）

The quantitative trait loci （QTLs） analysis for flower traits were performed based on three crossing of Coffea canephora in Indonesia. This study successfully identified 19 QTLs related to flowering. These QTLs consisted of 1） three QTLs associated with green candle flowering time located at linkage groups of A and D; 2） one QTL associated to white candle flowering time located at linkage groups of B; 3） two QTLs associated to blossom flowering time located at linkage groups of B; 4） two QTLs associated to number of flowers located at linkage groups of G and H; 5） five QTLs associated to score of flowers quality located at linkage groups of A, C and D; 6） five QTLs associated to number of star flowers located at linkage groups of D, E, F and G. Due to some QTLs are overlapping on the same linkage group, thus, these 19 QTLs for flower traits might be considered as 15 different ones which distributed on 14 regions of the eight linkage groups. Although pleiotropic genes might be the most likely explanation for the collocation of these QTLs, the present data are not sufficient to distinguish between a pleiotropic gene and a cluster of different loci controlling several traits. These results can be a first step for molecular breeding on Robusta coffee mainly in order to improve potential suitable characteristics such as number of flowers and number of normal flowers as well as to reduce adverse characteristics such as number of star flowers.

构建电子转移通道阻抑法筛选车前子中黄嘌呤氧化酶抑制剂成分

目的:构建黄嘌呤氧化酶(XOD)电子转移通道阻抑方法筛选车前子中XOD抑制剂成分。方法:将双壁碳纳米管(DWNTS)固定于玻碳电极表面,并在其上修饰XOD,构建XOD催化反应电子转移通道。应用循环伏安法监测通道中的电子转移信号,当抑制剂成分存在阻止XOD催化黄嘌呤(XAN)反应时,通道电子转移信号下降,藉此筛选XOD抑制剂。结果:循环伏安法可灵敏监测XOD催化反应通道中电子转移阻抑信号,利用该法对车前子中的4个代表性单体成分进行筛选,共筛选出2个XOD抑制剂,分别为毛蕊花糖苷(IC_(50)为8.4μg·m L^(-1))、乙基己基-苯羧酸酯(IC50为75.0μg·m L^(-1)),其中乙基己基-苯羧酸酯为新筛选出的XOD抑制剂。结论:电子转移通道阻抑筛选方法简单快捷,灵敏度与选择性高,筛选化合物用量低,在天然产物XOD抑制剂的筛选中具有很好的应用前景。