FACTORS AFFECTING CHLOROGENIC, QUINIC AND CAFFEIC ACID LEVELS IN SUNFLOWER KERNELS

SUMMARY— Location of the seed on the sunflower head and storage temperatures were related to chlorogenic, caffeic, and quinic acid levels. Kernels of freshly harvested sunflower seeds located near the center of the head were higher in chlorogenic acid than seeds located near the margin. The opposite was obtained for the caffeic acid content, and quinic acid did not exhibit a positional effect. Chlorogenic acid content decreased during storage at 5°C, 15°C, and 40°C for 120 days; seeds attained the same levels of chlorogenic acid but varied slightly among treatments. Relatively small changes occurred in the caffeic and quinic acids content during storage.     

超声波法提取蒲公英中的绿原酸

蒲公英中含有的绿原酸具有抗菌消炎等多种作用,研究并优化超声波提取蒲公英中绿原酸的最佳工艺参数.以蒲公英为原料,通过单因素试验,正交试验和方差分析确定最佳提取工艺.结果表明:超声波提取蒲公英中绿原酸的最佳工艺条件为乙醇浓度60%、pH=2料液比1:14、提取温度50℃、提取时间50 min,绿原酸提取率可达70%以上.     

雪莲果中绿原酸的提取工艺

以乙醇作溶剂,水浴加热回流提取雪莲果中的绿原酸,于紫外可见分光光度计上进行扫描.对比绿原酸标准品和雪莲果提取液的紫外扫描图谱,发现在330nm处都有一个最大吸收峰.在单因素试验的基础上确定以乙醇浓度、提取温度、提取时间、物料比作为试验因子进行L9(34)正交试验.绿原酸标准品标准工作曲线的线性方程:A=-0.12 575+59.185 27C,相关系数r=0.9997.通过正交试验,确定雪莲果中绿原酸的最佳提取条件为:乙醇质量分数为40%,物料比为1:18(g/mL),于沸水浴中回流提取时间为2.5 h.在最佳工艺条件下测得雪莲果中绿原酸含量为0.052%.     

TLC-UV法测定金银花中绿原酸

探讨建立实验室有效快速测定绿原酸含量的方法.以乙酸乙酯-甲酸-水(10:1:2)为展开剂,将样品A采用TLC法将金银花有效成分绿原酸与其他成分分离、定位后,用紫外分光光度计测定其含量;与UV法、HPLC法进行含量测定结果的比较.结果表明,TLC-UV法通过薄层层析收集绿原酸点后利用分光光度计测定含量,比单纯的TLC法测定含量准确,且此法测定绿原酸含量与HPLC法测定结果基本一致;TLC-UV法回收率达到96%,RSD为0.86%;精密度RSD为0.03%(n=7).     

BARLEY DORMANCY AND FATTY ACID COMPOSITION OF LIPIDS ISOLATED FROM FRESHLY HARVESTED AND STORED KERNELS

The influence of kernel surface lipids on barley dormancy was investigated. Kernels with surface lipids extracted by chloroform:methanol (2:1) germinated nearly as well as Intact kernels subsequent to steeping in either distilled water or a solution of formaldehyde (ca 800 mg/l). Both water-sensitivity and innate dormancy were reduced in intact and surface-lipid extracted kernels stepped in formaldehyde when compared with kernels steeped in distilled water. Differences in fatty acid composition occurred in both surface and total kernel lipids of grain held in storage. However, compositional changes in fatty acids could not be used to predict kernel dormancy since increasing germination properties of kernels during the storage period were influenced by environmental conditions at time of harvest and varietal differences.     

向日葵花黄色素的提取工艺

对向日葵花黄色素的提取进行初步的探索,优化向日葵花黄色素的提取工艺.通过有机溶剂浸提法,选择无毒、无残留的无水乙醇作为浸提剂,筛选乙醇浓度梯度,通过分光光度计分析,确定70%乙醇为最佳浸提剂.通过三因素三水平正交试验表明,浸提温度和浸提时间对向日葵花黄色素的提取影响较大.优化提取工艺为:向日葵花瓣(凉干)经粉碎后置于三角瓶中,依液料比40:1(mL/g)加入70%的乙醇,50℃恒温浸提3h,此时的吸光度为0.846.     

金银花中绿原酸提取工艺的优化

对金银花中绿原酸的提取方法进行了比较研究,探讨了乙醇回流法的最佳提取方法和最佳工艺条件,并采用微波和酶液处理金银花以改进乙醇回流法.乙醇回流法最佳条件是加10倍量75%乙醇,回流提取1.5 h.对于乙醇回流法的改善,微波筛选的最佳工艺条件是:在600W微波功率下,样品预浸时间24 h,辐射时间2min.纤维素酶处理的酶用量为0.5%浓度2mL,最适温度为40℃～50℃,最佳时间为3.0h.试验表明:优选得到的工艺简单、稳定、可行,微波及酶液处理均能显著提高绿原酸的得率.     

MEASUREMENT OF CHLOROGENIC ACID AND FLAVONOL GLYCOSIDES IN APPLE JUICE BY A CHROMATOGRAPHIC-FLUOROMETRIC METHOD

Methods are described that measure chlorogenic acid at concentrations as low as 1 mg/100 ml of juice and flavonol glycosides at levels as low as 0.2 mg/100 ml of juice. Results are given for several apple juices, indicating concentrations of chlorogenic acid ranging from 12–31 mg/100 ml juice. Flavonol glycosides in conventional juices were 0.4–0.7 mg/100 ml, while special juices had 6.5–8.5 mg/100 ml     

栓菌属漆酶催化儿茶素和绿原酸生物转化的动力学研究

为了掌握漆酶对不同种类苹果酚类化合物生物催化的特异性,以白腐菌漆酶为试材,儿茶素和绿原酸为模式底物进行了酶促反应动力学参数的测定.结果表明,漆酶催化儿茶素、绿原酸的转化产物最大吸收波长分别为442 nm、379 nm;反应最适温度均为55℃;最适pH对儿荼素为pH 6.0,pH 6.5两个值,对绿原酸为pH 5.5,pH 6.0两个值:儿茶素浓度0.5mol/L时.最适酶浓度为0.05 U/mL,2种底物的漆酶催化反应均符合米氏方程规律.在25℃温度条件下测得儿茶素和绿原酸两种底物的Km值分别为0.148 9,0.3390mol/L;Vmax分别为212.77,28.01 8A/(U·min).这为苹果加工中漆酶催化混合酚类化合物转化工艺的确定提供了依据.     

EXTRACTION OF α-GLUCOSIDASE FROM GERMINATED BARLEY KERNELS

α-Glucosidase activities were extracted from flour of lyophilized, germinated barley seeds. To establish conditions resulting in maximal extraction of α-glucosidase activity from flour of germinated barley, we tested different buffer pH's, extraction times and temperatures, and additions of sulfhydryl reducing reagents, salts, and detergents to the extraction buffer. More enzyme activity was extracted as the extraction buffer pH increased from 3 to 9. The sulfhydryl reagents studied did not significantly increase extractable activity. The extractable activity rose with increased NaCl concentrations up to 2 M. Of the six detergents tested, the zwitterionic detergent CHAPS was most effective in solubilizing α-glucosidase activity, and when combined with NaCl resulted in a doubling in extractable activity as compared with phosphate buffer at pH 8.0. Extraction time and temperature were not critical for the actual solubilization of activity but temperature was quite critical in retaining solubilized α-glucosidase activity in crude extracts.     

THE QUALITY OF VEGETABLE OIL FROM THREE VARIETIES OF SUNFLOWER SEEDS (HELIANTHUS ANNUUS)

ABSTRACT

Vegetable oils become susceptible to oxidation during their processing. The appropriate extraction and refining conditions of oil from two experimental cultivars (Madero‐91 and Cianoc‐2) of sunflower seeds and a commercial one (Victoria) as a control, were studied. Isopropyl alcohol was used in the extraction and refining, and compared with hexane. The refining was performed by the miscella method at 40, 50, 60 and 70%. Free fatty acids (FFA) and malonaldehyde analysis of crude oils afforded no significant differences among solvents and sunflower varieties. In refined oils, differences found with the miscella concentration, the malonaldehyde content and FFA content were not significant. Cianoc‐2 was the best source for oil production because of its lower values in FFA and malonaldehyde content.

PRACTICAL APPLICATIONS

The use of hexano in refining vegetable oil in Mexico is common, lack of knowledge about the use of new solvents and their impact on the processing conditions with sunflower seed cultivars is lack. The present work describes at lab scale, the work conditions, advantages and posibilities and limitations of the use on isopropyl alcohol in comparison with hexane and the use of three Mexican cultivar with this approach, with emphasize in oxidation conditions of refined vegetable oil.