A Research Note Stability of Anthocyanins from Zebrina pendula and Ipomoea tricolor in a Model Beverage

Anthocyanins from two sources with reported high stability, Ipomoea tricolor and Zebrina pendula, were compared with extracts from blackberries containing mainly cyanidin-3-glucoside (Cn-3-G) and a commercial enocyanin. The pigment samples were formulated in a sugar, citrate-phosphate buffer solution for storage at room temperature. Tristimulus color data and pigment retention were measured at periods up to 82 weeks. The Ipomoea pigments were the most stable. Zebrina and Cn-3-G samples were similar followed by enocyanin. Deacylated pigments from both Ipomoea and Zebrina were the least stable indicating that the acyl groups conferred stability.     

Stability of Anthocyanins from Tradescania pallida

The acylated, B-ring substituted anthocyanins of Tradescantia pallida (TPA) were extracted from the leaves with acidic water, purified on a Duolite-861 resin and incorporated into a model beverage. The beverage was composed of a citrate-phosphate buffer at pH values 3.5, 4.5 or 5.5, and 15% sucrose. Comparison samples contained cyanidin-3-glucoside from blackberries and a commercial sample of enocyanin from grapes. The TPA samples were much more stable than the other two, particularly at the higher pH values as judged by pigment retention and tristimulus color readings. The extra absorption band of the TPA samples at pH 5.5 indicated the samples were well colored. Addition of tannin and/or ascorbic acid resulted in marked pigment and color loss.     

Detection of Enocyanin in Cranberry Juice Cocktail by HPLC Anthocyanin Profile

Adulteration of cranberry juice products by enocyanin, a colorant from grapes, was detected by comparing HPLC chromatographic profiles of cranberry anthocyanins with those from enocyanin. Two peaks present in all enocyanin samples but not in cranberries were identified as delphinidin-3-glucoside and petunidin-3-glucoside. A group of unidentified pigments which eluted after the cranberry pigments was also present in enocyanin. It was possible by considering differences in the chromatograms to detect replacement of 5% or more of the expected amount of cranberry juice in cranberry juice cocktail by a solution of enocyanin. A CG-50 column was used to concentrate the pigments followed by chromatography on a polymer styrene column at pH 1.6. The method gives reliable results even on samples 18 months of age.     

Phenolic compound composition and antioxidant activity of fruits of Rubus and Prunus species from Croatia

Two fraction, one containing flavonols, flavan-3-ols, phenolic acids and the other containing anthocyanins, were isolated from Rubus (red raspberry, blackberry) and Prunus (sweet cherry, sour cherry) fruits to study their phenol content by HPLC and antioxidant activity using the DPPH test. Raspberries and blackberries were characterised by catechins and ellagic acid derivatives; sour and sweet cherries by phenolic acids. All fruits had relatively high anthocyanin content. Anthocyanins contributed more to the antioxidant activity of all fruits (∼90%) than flavonols, flavan-3-ols and phenolic acids (∼10%). A biphasic reaction was observed between DPPH^• radicals and phenols, with 'fast' and 'slow' scavenging rates which might be important in the biological activity of these fruits. Sour cherries and blackberries which stand out with the highest total phenol content (1416 and 1040 mg kg⁻¹) had also the strongest antioxidant activity (EC₅₀ = 807 and 672 g of fruit per gram of DPPH) and can be considered as good source of dietary phenols.     

Detection of Enocyanin in Cranberry Juice Cocktail by Color and Pigment Profile

Addition of enocyanin to cranberry juice cocktail can be determined by a four-step color and pigment profile. Enocyanin colorant is slightly more blue, therefore, a simple measurement of color will detect samples with 12% or less cranberry juice. Cranberry juice cocktail normally contains 25% cranberry juice. Anthocyanins and flavonoids, recoverable by a CG-50 ion exchange column, are lower in samples with 12% or less cranberry juice. Anthocyanin aglycones, found in grapes and not in cranberries, can be detected by paper chromatography in Formic reagent. Replacement of 50% of cranberry juice by a solution of enocyanin and citric acid, can be detected by paper chromatography of anthocyanins in 1% HCl in water.     

紫甘薯α-淀粉酶酶解液中紫色素的分离与糖液发酵生产乙醇的研究

本文综合利用紫甘薯资源,同时获得紫色素和糖液,糖液发酵制备乙醇。以大孔树脂分离紫甘薯α-淀粉酶酶解液后获得紫色素与糖液,考察氮源种类与添加量、酵母接种量、发酵时间对糖液发酵产乙醇含量的影响,通过正交实验优化糖液发酵生产乙醇工艺。实验结果表明,紫甘薯酶解液经HPD400型大孔树脂分离,紫色素的色价(E_{1 cm}1%)达到86.3(波长为530 nm),糖液中总糖含量达到55.5 mg/L;(NH₄)₂SO₄作为发酵氮源,(NH₄)₂SO₄添加量为3.0 g/100 mL、酵母接种量为1.5 mL、发酵时间为7 d,可得到13.0%vol乙醇。此方法获得了紫甘薯色素,副产物糖液发酵可生产乙醇,为紫甘薯的综合利用提供了思路。     

紫薯醋发酵工艺优化及品质分析

采用单因素结合响应面法优化紫薯醋酸发酵条件,同时发酵得到紫薯醋和紫薯色素回添醋,并对2种醋和紫薯原料的品种指标进行测定及比较。优化后的紫薯醋酸发酵条件为发酵时间11 d、初始酒度7.35%vol、装液量28%,此条件下,总酸含量为6.92 g/100g。与原发酵工艺相比,紫薯色素回添醋除总糖和维生素含量较低外,其总酸、总酯、总多酚、总黄酮、花青素含量和抗氧化能力均显著优于紫薯醋(P<0.05)。与紫薯原料中的活性成分相比,紫薯醋中总多酚、总黄酮、花青素含量较原料分别损失75.59%、63.63%和72.75%,采用新发酵工艺可使损失率分别降低10.34%、15.61%和42.93%。挥发性成分分析显示2种紫薯醋中鉴定出的挥发性成分的化合物数量相差不大,种类却有较大差异。同时,紫薯花青素的提取过程会导致一些对醋品香气有贡献的化合物损失。     

Fluctuations in the Levels of Antioxidant Compounds and Antioxidant Capacity of Ten Small Fruits During One Year of Frozen Storage

The fluctuations in antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl, 2,2´-azinobis (3-ethylbenzthiazoline-6-sulphonic acid), and ferric reducing/antioxidant power assays), total phenol, total flavonoid, and total anthocyanin contents of 10 small fruits (sweet cherries, sour cherries, strawberries, red currants, raspberries, blackberries, hawthorn, cornelian cherries, and red and white grapes) were monitored during storage at ?20°C. After one year in storage, all varieties except hawthorn and white grapes retained equal or slightly greater total phenol content in comparison to the initial values. The total flavonoid and total anthocyanin levels also remained stable or even increased after 12 months in all fruits exept hawthorn and strawberries. Red currants and raspberries exhibited optimal preservation of antioxidant capacity, while hawthorn showed a decrease in the antioxidant capacity during different time points in storage as well as at the end of storage. Analyzed fruits were classified into four main groups based on hierarchical cluster analysis.     

紫薯花色苷的理化性质研究

对紫薯花色苷的理化性质进行了研究,结果表明,其在中性偏酸的条件下呈现鲜艳的红色或悦目的紫色;对H_2O_2、Na_2SO_3以及光线表现出不稳定性;水溶液具有色泽或者氧化还原性的金属离子也会影响其色泽;具有良好的热稳定性;对于常用的食品添加剂如蔗糖、NaCl、防腐剂等具有良好的配伍稳定性;具备良好的贮藏稳定性,常温避光的情况下能放置5个月无明显变化,紫薯花色苷是优良的天然色素来源.     

紫薯色素两种提取方法的比对研究

以紫薯为原料,采用微波和超声波对紫薯色素提取方法进行对比研究,正交法探讨两种方法的最佳提取条件和参数。结果表明：微波提取最佳条件为溶剂50%酸化乙醇、料液比1:10(g/mL)、辐射时间12min、温度75℃;超声波提取最佳条件为溶剂60%酸化乙醇、料液比1:30(g/mL)、超声时间30min、超声温度60℃;在两种方法的最佳条件下清除羟自由基,微波清除效率高。综合比较,微波方法更优。     

紫红薯及玫瑰花色素稳定性的研究

紫红薯是近年来我国兴起的红薯新品种,含有丰富的花青素,该类色素在加工过程中稳定性很差.本文主要以宁紫4号为原材料,在相同的条件下与天然花卉的花青素比较它们的稳定性,为食品加工提供一定的参考依据.结果表明:紫红薯色素热稳定性较好,耐酸,常见金属离子中Fe~(3+)和Fe~(2+)引起紫红薯色素的损失较大.而玫瑰花色素在弱酸下较稳定,常见金属离子中Fe~(3+)和Fe~(2+)对玫瑰花色素影响较大,Al~(3+)、Cu~(2+)、Zn~(2+)对玫瑰花色素影响相对较小.两种物质的色素对碱都很敏感,碱使色泽加深.     

DPPH法测定紫红薯提取物清除自由基的能力

通过DPPH法测定紫红薯色素抗氧化、清除自由基的能力.试验表明,随着紫红薯色素浓度的增大,其抗氧化能力也相应提高.与VC和芦丁比较,紫红薯色素抗氧化、除自由基能力低于VC,但略高于芦丁.紫红薯色素清除DPPH自由基的半抑制量为163 mg/mL,其清除自由基能力AE为0.006 1.     

响应面试验优化紫薯皮色素提取工艺及其稳定性分析

通过Box-Behnken试验设计和响应面分析法,对紫薯皮色素的提取条件进行了优化,并且研究了各种物理及化学因素对紫薯皮色素稳定性的影响。结果,得出最佳提取条件为：酸醇体积比1∶1（0.5%柠檬酸酸化）、料液比1∶60（g/mL）、提取温度50 ℃、提取时间20 min。在此优化方案条件下,理论吸光度预测值为0.843,实际吸光度为0.838。紫薯皮色素的稳定性研究结果显示：日光暴晒条件下光稳定性比较差,自然光和避光条件下,稳定性良好;4～60 ℃的温度范围内具有非常好的热稳定性;紫薯皮色素在含有K＋、Ca2＋、Na＋、Zn2＋等金属离子的溶液中表现比较稳定的状态,在含有Mg2＋、Cu2＋、Mn2＋、Fe3＋等金属离子的溶液中产生沉淀;酸性条件有利于紫薯皮色素的稳定性,而碱性条件不利于紫薯皮色素的稳定性;最大安全使用范围内,紫薯皮色素稳定性几乎不会受到苯甲酸、山梨酸等一系列常用食品添加剂溶液的影响,可作为食品着色剂。     

Evaluation of in vitro antimicrobial activity of Thai basil oils and their micro-emulsion formulas against Propionibacterium acnes

The aim of this study was to evaluate the efficacy of Thai basil oils and their micro-emulsions, on in vitro activity against Propionibacterium acnes. An agar disc diffusion method was employed for screening antimicrobial activity of the essential oils of Ocimum basilicum L. (sweet basil), Ocimum sanctum L. (holy basil) and Ocimum americanum L. (hoary basil) against P. acnes. Minimum inhibitory concentration (MIC) values of the basil oils were determined using an agar dilution assay. The obtained results indicated that the MIC values of sweet basil and holy basil oils were 2.0% and 3.0% v/v, respectively, whereas hoary basil oil did not show activity against P. acnes at the highest concentration tested (5.0% v/v). Gas chromatography-mass spectrometry analysis revealed that methyl chavicol (93.0%) was the major compound in sweet basil oil, and eugenol (41.5%), gamma-caryophyllene (23.7%) and methyl eugenol (11.8%) were major compounds in holy basil oil. Hoary basil oil contained high amounts of geraniol (32.0%) and neral (27.2%) and small amounts of methyl chavicol (0.8%). The Oil-in-water (o/w) micro-emulsions of individual basil oils with concentrations corresponding to their MIC values were formulated. The stable o/w micro-emulsion system for basil oil consisted of 55.0% v/v water phase, 10.0% v/v oil phase (2.0 or 3.0% v/v sweet basil or 3.0% v/v holy basil oil plus 7.0% v/v isopropyl myristate), 29.2% v/v polysorbate 80 and 5.8% v/v 1,2-propylene glycol. Hydroxyethylcellulose at a concentration of 0.5% w/v was used as thickening agent. According to the disc diffusion assay, the formulations containing sweet basil oil exhibited higher activity against P. acnes than those containing holy basil oil, and the thickened formulations tended to give a lower activity against P. acnes than the non-thickened formulations. The prepared micro-emulsions were stable after being tested by a heat-cool cycling method for five cycles. These findings indicate the possibility to use Thai sweet and holy basil oil in suitable formulations for acne skin care.     

紫薯色素提取工艺及其功能活性研究进展

综述近年来中国紫薯色素提取工艺及其功能活性,展望该色素的研究方向及应用前景。     

紫甘薯肉丸的研制

以提取色素后的紫甘薯淀粉为原料,研究紫甘薯肉丸的最佳配方,选取紫甘薯淀粉添加量、大豆分离蛋白添加量、卡拉胶添加量3个影响因素进行正交试验。结果表明:2号肉30%、2:8碎肉25%、肥碎15%、食盐1.3%、味精0.3%、鸡蛋6%、鲜姜4%、鲜葱5%、磷酸盐0.4%、料酒0.5%、白胡椒0.1%、紫甘薯淀粉10%、大豆分离蛋白3%、卡拉胶0.4%为最佳配方。所制得的紫甘薯肉丸色泽漂亮,弹性和组织状态良好,口感细腻,咀嚼感强。     

甜橙加工综合利用研究进展

甜橙营养丰富,可以加工成多种产品。综述了国内外甜橙果肉加工及其皮渣综合利用研究进展,详细介绍了果肉加工成品橙汁、果酒,皮渣提取产物甜橙膳食纤维、橙皮精油、橙皮果胶、橙皮色素以及皮渣转化产物饲料、酶制剂的研究进展,以期为提高甜橙综合利用率、提高甜橙附加值提供参考依据。     

Multi-element survey of wild edible fungi and blackberries in the UK.

A survey of 12 metals including lead (Pb), copper (Cu), cadmium (Cd), mercury (Hg), arsenic (As) and platinum (Pt) was carried out using ICP-MS in 34 samples of wild fungi and 48 samples of wild blackberries collected from sites across the UK. On a fresh weight basis (mg/kg) levels of Pb were in the range 0.003-5.990, Cu 0.596-34.800, Cd<0.001-19.6, Hg<0.001-4.150, As 0.001-0.972 and Pt (microg/kg) 0.006-0.200, with higher concentrations found in fungi than in blackberries. The results of the survey showed that the concentrations of the metals were consistent with previous studies, where available. Concentrations in wild fungi of Pt, tin (Sn), and titanium (Ti) were significantly higher at urban sites than at rural sites. Urban blackberries had significantly higher levels of Pb, Ti, and Cd than rural ones, but lower levels of manganese (Mn). Pb, Ti and Sn concentrations were significantly higher in blackberries sampled near main roads rather than in rural areas.     

紫甘薯花色苷生产中紫薯蛋白的分离与富集

为了将紫甘薯色素提取液中的花色苷与蛋白分离,选择不同型号的大孔吸附树脂对紫甘薯色素提取液进行了吸附与解吸实验,筛选出特异性吸附提取液中色素的树脂.并利用大孔吸附树脂对流出液中紫甘薯蛋白进行富集.实验结果表明:ADS-7型树脂能有效将提取液中的花色苷与蛋白分离,分离程度达70%以上;流出液以1BV/h、2mg/mL流经树...     

紫甘薯色素的提取工艺研究

为了给紫甘薯色素的生产和使用提供理论依据,以国产紫甘薯为原料,研究了醇和有机酸溶液等溶剂提取色素的条件,考察提取液浓度、料液比、提取次数和浸取时间等因素的影响.通过单因素试验和正交试验,确定超声波提取最佳工艺是:紫甘薯样品预先浸泡4 h,采用柠檬酸浓度为10%,料液比为1:30,超声功率为300 W,提取时间为25 m...