玉米醇溶蛋白生产新工艺的研究

通过对脱色步骤和沉淀步骤的改进，找到一条玉米醇溶蛋白生产的新工艺，分别研究了脱色，提取和沉淀３个步骤中各种工艺参数生产的影响，摸索出本工艺的最佳工艺条件：脱色：乙醇回流温度下，萃取５ｈ；提取：温度６０℃，时间２ｈ，乙醇浓度７０％，液固比１０：１（ｍｌ／ｇ）；沉淀：沉淀温度０℃，沉淀剂与醇溶蛋白浓缩提取液比３０：１（ｖ／ｖ）。     

Provitamin‐A and xanthophyll carotenoids in vegetables and food grains of nutritional and medicinal importance

This study reports carotenoid composition of vegetables (n = 56), cereals (n = 12), pulses and legumes (n = 12), analysed by HPLC. It was hypothesised that food grains, like vegetables may be good sources of carotenoids. Amongst vegetables, higher level (mg/100 g dry weight) of lutein (210–419) was detected in green/red/capsicum and yellow zucchini, whilst zeaxanthin was dominant in kenaf (4.59). β‐Carotene (mg/100 g dry weight) was higher in green capsicum and kenaf (48,159) whilst carrot, ivy gourd and green capsicum contain α‐carotene (22–110). Amongst food grains, chickpea, split red gram and flaxseed contain higher levels (μg/100 g dry weight) of lutein (185–200) whilst zeaxanthin level was highest in puffed chickpea (1.8). Red unpolished parboiled rice was richest (μg/100 g dry weight) in β‐carotene (67.6) whilst whole black gram contained higher levels of α‐carotene (52.7). Thus, results indicate that chickpea and red unpolished parboiled rice are good sources of carotenoids. These carotenoid‐rich vegetables and grains may be exploited to meet the lutein and β‐carotene requirement.     

玉米蛋白粉中黄体素和玉米黄素的分离与定性

利用溶剂萃取、薄层层析对玉米蛋白粉中黄体素和玉米黄素进行了提取和分离.通过薄层层析的相对迁移率、与AgNO3的显色反应、紫外 可见吸收光谱、高效液相色谱保留时间及液质联用所得到的相对分子质量信息,对分离所得黄体素和玉米黄素进行了定性研究,为玉米蛋白粉中黄体素和玉米黄素的进一步研究和开发利用奠定了基础.     

玉米中类胡萝卜素的研究进展

玉米中富含以玉米黄素、叶黄素为主的类胡萝卜素,它们具有很强的抗氧化性能,对人体有保健作用,近年来又被发现对预防癌症有一定功效。文章综述了国内外有关玉米中类胡萝卜素相关研究进展,包括类胡萝卜素组成、性质、功能探索及制备研究等。     

Photoprotective Role of Photosynthetic and Non-Photosynthetic Pigments in Phillyrea latifolia: Is Their “Antioxidant” Function Prominent in Leaves Exposed to Severe Summer Drought?

Carotenoids and phenylpropanoids play a dual role of limiting and countering photooxidative stress. We hypothesize that their “antioxidant” function is prominent in plants exposed to summer drought, when climatic conditions exacerbate the light stress. To test this, we conducted a field study on Phillyrea latifolia, a Mediterranean evergreen shrub, carrying out daily physiological and biochemical analyses in spring and summer. We also investigated the functional role of the major phenylpropanoids in different leaf tissues. Summer leaves underwent the most severe drought stress concomitantly with a reduction in radiation use efficiency upon being exposed to intense photooxidative stress, particularly during the central hours of the day. In parallel, a significant daily variation in both carotenoids and phenylpropanoids was observed. Our data suggest that the morning-to-midday increase in zeaxanthin derived from the hydroxylation of ß-carotene to sustain non-photochemical quenching and limit lipid peroxidation in thylakoid membranes. We observed substantial spring-to-summer and morning-to-midday increases in quercetin and luteolin derivatives, mostly in the leaf mesophyll. These findings highlight their importance as antioxidants, countering the drought-induced photooxidative stress. We concluded that seasonal and daily changes in photosynthetic and non-photosynthetic pigments may allow P. latifolia leaves to avoid irreversible photodamage and to cope successfully with the Mediterranean harsh climate.     

玉米黄素制备工艺中强碱的影响研究

玉米黄素和叶黄素共同构成视黄斑色素,视黄斑色素在保护眼健康方面起到非常重要的作用.本文以叶黄素为原料,在碱性条件下经异构化反应制备玉米黄素,研究了有机碱液的加入方式、有机碱液的加入量对异构化反应的转化率、收率的影响,分析了造成这些影响的可能原因.实验结果表明,叶黄素异构化制备玉米黄素过程中应控制有机碱液的加入量,并以滴...     

高效液相色谱法同时测定护眼保健品中叶黄素和玉米黄质

目的 建立高效液相色谱法(high performance liquid chromatography, HPLC)同时测定护眼保健品中叶黄素和玉米黄质的分析方法。方法 样品用胰酶氯化钠预处理后, 经无水乙醇及石油醚提取, 在55 ℃水浴中用40%氢氧化钾-甲醇溶液皂化30 min, 无水乙醇稀释后, 选用色谱柱YMC Carotenoid S-5 (250 mm× 4.6 mm, 5 μm), 以甲醇:三氯甲烷(4:1, V:V)为流动相, 流速为1.5 mL/min, 柱温为25 ℃, 于445 nm波长处测定样品。结果 叶黄素在0.3906~12.4979 μg/mL范围内线性关系良好, 相关系数r2为0.9999, 平均回收率为91.5%~95.2% (n=9), 检出限为0.0075 μg/g; 玉米黄质在0.1474~4.7184 μg/mL范围内线性关系良好, 相关系数r2为1, 平均回收率在98.6%~110.2% (n=9), 检出限为0.0120 μg/g。结论 该方法快速、稳定, 能够适用于护眼保健品中叶黄素和玉米黄质的同时测定。     

高效液相色谱法测定枸杞相关食品中枸杞酸和玉米黄质二棕榈酸酯的含量

目的 建立高效液相色谱法分析枸杞原料、提取物和相关配方产品中枸杞酸和玉米黄质二棕榈酸酯的含量。方法 采用Poroshell 120 HILIC柱,以乙腈-磷酸水（90:10, V:V）为流动相进行分离枸杞酸,在紫外检测波长235 nm下进行检测,外标法定量。用Dionex Acclaim C30柱,以甲醇-甲基叔丁基醚为流动相进行梯度分离玉米黄质二棕榈酸酯,在紫外检测波长452 nm下进行检测,外标法定量。结果 枸杞酸的检出限为10 mg/kg,定量限为30 mg/kg;在10～200 mg/L的浓度范围内线性良好,相关系数为0.9999;枸杞原料、提取物和相关配方产品中的加标回收率在84.3%～98.1%之间,相对标准偏差(relative standard deviation, RSD)在1.3%～4.7%之间;精密度的RSD在0.74%～1.2%之间;重复性的RSD分别为1.3%～3.1%之间。玉米黄质二棕榈酸酯的检出限为10 mg/kg,定量限为30 mg/kg;在0.5～10 mg/L的浓度范围内线性良好,相关系数为0.999;枸杞原料、提取物和相关配方产品中的加标回收率在88.6%～98.6%之间,RSD在1.5%～4.5%之间;精密度的RSD在1.2%～2.1%之间;重复性的RSD在2.0%～4.5%之间。结论 本方法操作简便,快速,分离度和准确度高,可用于枸杞原料、提取物和相关配方产品的质量控制。     

叶黄素和玉米黄素抑制口腔上皮细胞癌增殖的实验研究

为阐明玉米蛋白粉类胡萝卜素提取物叶黄素和玉米黄素对人口腔上皮癌细胞株KB凋亡的诱导作用,探讨其分子生物学机制。本文采用单细胞凝胶电泳、DNA凝胶电泳、流式细胞术检测叶黄素和玉米黄素诱导口腔癌细胞凋亡的情况。结果发现:单细胞凝胶电泳显示玉米蛋白粉叶黄素和玉米黄素能造成KB细胞DNA损伤、DNA凝胶电泳显示能使KB细胞DNA发生明显的降解,DNA周期分析主要阻断口腔癌细胞由G1向S期转变;流式细胞仪检测明显抑制人口腔癌细胞株KB中bcl-2基因的蛋白表达,明显升高p53、Bax基因的蛋白表达;说明玉米蛋白粉类胡萝卜素提取物叶黄素和玉米黄素具有明显抑制口腔上皮癌细胞增殖、并诱导其凋亡的作用。