Anthocyanin Pigments of Sweet Potatoes–Ipomoea batatas

The anthocyanin pigments of red sweet potato roots (Impomoea batatas) were isolated, purified and identified by HPLC and conventional paper chromatographic, spectral and chemical methods. Two major pigments and two minor pigments were present in fresh tissue slices extracted with boiling 1% HAc methanol. Tissues extracted cold yielded 11 or more pigments probably from degradation of the two major pigments. One major pigment was identified as peonidin-3-diglucoside-5-glucoside with three molecules of ferulic acid and one molecule of caffeic acid. The other major pigment was peonidin-3-diglucoside-5-glucoside with two molecules of ferulic acid and one caffeic acid.     

Properties of red pigments prepared from geniposidic acid and amino acids

Red pigments formed from geniposide and amino acids were studied. Geniposide, the principal iridoid glucoside contained in the fruit of Gardenia jasminoides Ellis, was hydrolysed to geniposidic acid as a precursor for the pigment. The pigments prepared anaerobically with arginine or glutamic acid under acidic conditions with a large excess of citric acid, were reddish purple and had properties governed by the electrostatic character of the amino acid. Relative molecular masses of these pigments were determined to be several thousand by gel filtration. The pigments showed good stability to heat and pH, but were gradually bleached by light. The safety of the pigments was evaluated by studing their oral acute and the 5‐month oral toxicity of arginine‐red pigment using mice. The pigments were considered to be of low toxicity. © 1999 Society of Chemical Industry     

Carotenoid pigment loss of freeze-dried plant samples under different storage conditions

Enzyme extracted carotenoid pigments from orange peel, sweet potato and carrot samples were freeze-dried and stored at 25°C light, 25°C dark, 4°C and 40°C. Color losses of freeze-dried pigments under these storage conditions were compared with the non-dried samples. For the freeze-dried samples, the highest pigment loss was in carrot pigments stored at 40°C (98.1 g/100 g) while the lowest loss was in sweet potato pigments stored in 4°C (11.3 g/100 g) during 45 days of storage. For all three samples, pigment loss was minimum at 4°C and maximum at 40°C as expected. Storage under light did not have significant effect on the carotenoid loss compared with the samples stored at dark. Freeze-drying lowered the pigment loss for all samples under all storage conditions.     

彩色马铃薯块茎色素初步分析

提取四个彩色马铃薯新品系皮和肉中的色素,对色素液进行紫外及可见光谱分析、感官分析及薄层层析分析。结果表明,彩色马铃薯色素主要为花青素类色素,其在酸性条件下比在碱性条件下稳定,紫色马铃薯中含有的花色苷种类比红色马铃薯多,层析系统7（正丁醇∶冰乙酸∶水=3∶1∶3）对色素的分离效果最好。根据色素层析的Rf值和色素的紫外-可见光谱特点,参考已有相关资料,初步判断在紫色马铃薯中的色素主要是锦葵色素衍生物,而红色马铃薯中的色素主要是天竺葵色素衍生物。研究结果可以为食品工业天然色素源的探索和彩色马铃薯的综合利用提供参考。      

Characterization of Red Radish Anthocyanins

Red radish (Raphanus sativus L.) anthocyanins were extracted from liquid nitrogen powdered epidermal tissue using acetone, partitioned with chloroform and isolated using C-18 resin. The monomeric anthocyanin content, determined by pH-differential, was 154 ± 13 mg/100g epidermal tissue (pelargonidin-glucoside basis). Thermal processing of radishes showed that the pigments were stable to heat. Four major pigments were identified by Mass Spectroscopy, HPLC, and spectral analyses as pelargonidin-3-sophoroside-5-glucoside derivatives. The two major pigments were acylated with malonic acid and either ferulic or p-coumaric acid. The two other pigments were acylated with only ferulic or p-coumaric acid. Acylation increased pigment resistance to acid hydrolysis.     

Stability of red beet pigment concentrate in maize starch

Two pigment concentrates, differentiated as dark (D) and rose (R), were prepared from fermented red beet (Beta vulgaris L var rubra) and applied to two types of maize starch, industrial (IS) and modified (MS). The samples were stored for 191 days at room temperature. The decay of the two red pigments in the two maize starches was DIS 12.70%, DMS 9.43%, RIS 14.15%, RMS 8.54% and followed a first order reaction. The modified maize starch was found to be the most suitable carrier of the pigment. Water activity played a determining role in this result.     

红心萝卜色素分布及其抑菌特性分析

为研究不同红心萝卜色素含量及其分布特性,探究红心萝卜色素的稳定性和抑菌性,本文采用超声波辅助法提取4种红心萝卜的色素,比较色素分布差异,综合分析色素稳定性和红心萝卜色素的抑菌特性。结果表明,4种萝卜中,胭脂萝卜色素总量最高(0.039 mg/g)。萝卜个体内部色素存在差异,萝卜皮中的色素含量显著高于萝卜内部其他部位(P<0.05)。提取色素对高温(≥60 ℃)较为敏感,在pH=7时色素较稳定,抗Fe³⁺、Al³⁺的干扰能力较弱;耐还原能力比耐氧化能力强;柠檬酸和维生素C对色素有保色作用,蔗糖和食盐对色素稳定性影响不显著,且对大肠杆菌和金黄色葡萄球菌均有抑制作用。     

红曲黄色素在不同食品体系中的应用与探讨

将红曲黄色素油树脂以直接添加或制成微胶囊粉末添加到不同食品体系（液体、半固体和固体）中,采用分光测色仪考察颜色变化,分析其在不同食品体系中的稳定性,进一步对其变色的原因及机理进行探讨。结果表明,在软饮料体系中添加红曲黄色素能保持产品鲜艳的黄色,但在黄油曲奇饼干和卡仕达酱中,红曲黄色素的添加会使产品颜色变红,其中微胶囊在卡仕达酱中对色素的色调具有一定的保护作用。红曲黄色素（未知色素组分,非红曲素）能够与食品中未解离的氨基反应生成红色色素,从而导致其颜色色调变红。     

单宁酸对三种天然色素辅色作用的评价

本文运用紫外-分光光度计法和CIELab法评价单宁酸对甘蓝红色素、黑米色素和红树莓色素三种天然色素的辅色作用。结果表明,随着辅色剂浓度的增加,红树莓色素和黑米色素最大吸收波长发生红移,总色差逐渐变大,而甘蓝红色素的总色差也逐渐变大,但最大吸收波长未发生移动。在p H2.0⁶.0的范围内,随着缓冲溶液的p H变化,加入辅色剂后,体系的亮度、彩度和色相都发生变化,且亮度对于总色差变化的相对贡献率最大。在单宁酸的辅色过程中p H=4时,甘蓝红色素和红树莓色素总色差的变化最明显;黑米色素则在p H=3和5时变化明显。      

J. Cosmet. Sci., 59, 431–440 (September/October 2008)Red pigment from Lithospermum erythrorhizon by supercritical CO2 extraction

In this study, a stable red pigment was prepared from Lithospermum erythrorhizon via supercritical carbon dioxide extraction. The optimal extraction conditions were 400 bar and 60°C. The patch tests indicated that up to 10% of the red pigment was acceptable from a skin irritation standpoint. According to the results of the CIE LAB chromaticity test, the color difference was acceptable when compared to commercial synthetic red pigments. The light-illuminated color stability test indicated that the pigment was more stable than the red pigment extracted with ethanol. The higher stability was also demonstrated in the DPPH anti-oxidant activity test. The supercritical red pigment harbored elevated amounts of shikonin and derivatives, and appears to be usable as a stable red pigment for cosmetic color products.     

Stabilization of Red Beet Pigments with Isoascorbic Acid

Isoascorbic acid was investigated as a stabilizer for red beet pigments. Sterilized samples of red beet juice containing 0.05–1.0% isoascorbic acid, with the pH adjusted to 3, 5, or 7, were stored under artificial light or in darkness at 25°C or at 5°C. The best pigment preservation was obtained with 0.1% added isoascorbic acid. After 30 days storage at 25°C, samples at pH 5 containing 0.1% isoascorbit acid retained 52% (under light) and 65% (in darkness) of the red beet pigments, whereas the controls faded to yellow within 6 days under the same conditions.     

Degradation patterns and stability predictions of the original reds and amino acid derivatives of monascus pigments

The original red isomers and l-phenylalanine derivative isomers of monascus pigment, which have a side chain of either C₅H₁₁ or C₇H₁₅, were produced via Monascus fermentation, and then purified. The degradation patterns of the pigments relating to incubation conditions were investigated. For all tested compounds, a total of seven major fragments were formed during incubation, five in presence of sunlight irradiation and two with no sunlight. The red isomers R5 and R7 showed the same pattern whereas the L-Phe derivative isomers P5 and P7 exhibited another pattern. All of the pigments appeared to be highly sensitive to sunlight irradiation considering that with sunlight, diverse fragments were produced and the side chains C₅H₁₁ and C₇H₁₅ were degraded. The fragments are thought to be formed via degradation and combination reactions of pigments based on a comparison of the fragment molecular masses. Theoretically stable isomers of an original red pigment and some amino acid derivatives were selected based on a comparison of their Hartree conformational energies, which were estimated using geometric optimization based on ab initio molecular orbital calculations. The greater stability of amino acid derivatives was confirmed based on maximum UV-absorption wavelengths and isomer population rates.     

Effect of ascorbic acid on the stability of β‐carotene and capsanthin in paprika (Capsicum annuum) powder

The effect of ascorbic acid, light, and storage on the stability of the pigments β‐carotene and capsanthin in red pepper (Capsicum annuum) powder has been elucidated by determining the amount of pigment in samples treated by various concentrations of ascorbic acid. Determination of pigment concentration has been performed after different storage times using high‐performance liquid chromatography. The dependence of the concentration of pigments on the concentration of ascorbic acid, presence of light and the storage time has been assessed by stepwise regression analysis. The concentration of pigments decreased at longer storage time and increased at higher concentration of ascorbic acid, β‐carotene being more sensitive towards storage time and concentration of ascorbic acid than capsanthin. Interaction between the effects of light and storage time, and light and concentration of ascorbic acid has been established.     

红叶甜菜红色素的稳定性研究

采用80% 乙醇为提取溶剂,将提取的色素液在230～700nm 范围内进行紫外扫描,而后分别探讨碳水化合物、pH 值、温度、氧化剂还原剂、光照、金属离子对色素在紫外和可见光区的稳定性的影响。结果表明：该色素在紫外光区有两个吸收峰,波长分别为270、334nm,可见光区有两个吸收峰,波长分别为538、666nm;红叶甜菜红色素对热比较稳定,但不耐高温;pH 值对色素颜色影响不是很大,除pH10 以外;碳水化合物对其影响不显著;其抗氧化能化较弱;自然光照射一定时间会褪色;大多数金属离子对其无影响;而Fe3+ 等少数金属离子对色素有影响。     

桃金娘色素稳定性及初步分离研究

研究了桃金娘色素的稳定性和理化性质,并对其进行了初步分离纯化,为桃金娘色素的推广应用提供理论基础。研究结果表明,桃金娘色素易溶于酸性水溶液、酸性醇溶剂,不溶或难溶于非极性溶剂;在溶液pH小于4.0时桃金娘色素对光、热有较好的稳定性,其最大吸收波长为516nm;耐强氧化剂和还原剂较差;Zn2+、K+、Al3+、Na+、Ca2+离子对桃金娘色素有不同程度的保护和增色作用,但Mg2+、Fe3+离子降低色素的稳定性。经过葡聚糖凝胶LH-20柱层析和高效液相色谱分离纯化,表明桃金娘色素主要由4种色素组成。     

Modification of the Schricker Nonheme Iron Method to Minimize Pigment Effects for Red Meats

A calorimetric nonheme iron assay procedure for meat was modified to avoid pigment effects in determining the nonheme iron content of red meats. The modification consisted of mixing the red meat sample with NaNO₂ before incubation with an acid mixture to minimize the breakdown of heme pigments into nonheme iron, and inclusion of a second blank for the brownish color of the incubated liquid phase, in addition to the reagent blank.     

Antioxidative activity and emulsifying properties of cuttlefish skin gelatin–tannic acid complex as influenced by types of interaction

The non-covalent interaction between cuttlefish skin gelatin and tannic acid was observed in gelatin modified with unoxidized tannic acid at pH 7, whereas covalent interaction was found in gelatin modified with oxidized tannic acid at pH 9. Degree of tannic acid incorporation into gelatin via non-covalent interaction was more pronounced than that found via covalent interaction as evidenced by lowered free amino group content and increased total phenolic content and hydroxyl group and aromatic ring determined by FTIR. Gelatin modified with oxidized tannic acid had the slight decrease in surface hydrophobicity, with no changes in particle size distribution of the emulsions. Modification of gelatin with tannic acid, especially via non-covalent interaction, increased in vitro antioxidative activity, compared with the control gelatin. Gelatin modified with tannic acid via covalent interaction rendered the emulsion with high stability and could inhibit lipid oxidation of menhaden oil-in-water emulsion effectively throughout the storage of 12 days.

Industrial relevance

Cuttlefish skin gelatin modified with tannic acid possessing both emulsifying activity and the improved antioxidative activity can be used as a natural and safe additive in food industry. Therefore, cuttlefish skin, a by-product from seafood processing industry, can be produced as the high value added product with wider applications.     

常用天然色素抗氧活性的研究

对花青素类、黄酮类、类胡萝卜素类和醌类等十四种常用天然色素的抗氧活性研究表明:姜黄色素、两种高粱色素、可可壳色素、葡萄皮色素和洋葱色素具有较强的抗氧活性;紫草红色素、紫胶红色素、叶绿素铜钠盐、栀子黄色素和辣椒红色素具有一定的抗氧活性;甜菜红色素仅有一点抗氧活性;而红曲米色素和栀子蓝色素不具有抗氧活性。     

超声波辅助提取黑糯玉米芯色素稳定性的研究

运用超声波辅助技术提取黑糯玉米芯色素，研究了pH、光照、温度、氧化剂、还原刺、金属离子、共存物质对黑糯玉米芯色素稳定性的影响，并与相同条件下常规提取的黑糯王米芯色素进行比较。结果表明：光照、温度对两种方法提取出的色素无显著性影响；过氧化氢、亚硫酸钠、维生素C溶液对黑糯玉米芯色素影响较大；金属离子中的Fe^2＋、Fe^2＋、Sn^2＋对黑糯玉米芯色素稳定性影响较大，食品中常用的葡萄糖、蔗糖对色素有一定的降解作用；防腐剂苯甲酸钠对色素有一定的降解作用，且浓度越大，影响越大。柠檬酸、苹果酸、可溶性淀粉对色素溶液有增色作用；超声波辅助提取的色素和常规法提取的色素的稳定性基本一致。     

The influence of lactic acid fermentation process of red beet juice on the stability of biologically active colorants

Lactic acid fermentation can have preservative effect on red beet juice. The behavior of the pigment in the fermented juice was investigated and the results were compared with those of non-fermented juice. Two red beet varieties (Czerwona Kula and Chrobry) were used in our experiment. Three probiotic bacteria and three infant intestinal microbiota of Lactobacillus sp. were selected for beet juice fermentation.Lactic acid fermentation influenced both red and yellow pigments. In the two beetroot varieties (Chrobry and Czerwona Kula) studied, the dominant red-violet pigment components were betanin, isobetanin, while vulgaxanthin I was the major yellow pigment. Betanin was the main red-violet component in juices before fermentation. After fermentation also betanidin and isobetanidin were observed. Huge amounts of betanidin were found especially in fermented Chrobry juice.It was observed that fermented juice from Chrobry cultivar contained higher betanidin than betanin levels. Contrarily, in juice from Czerwona Kula cv., betanin level was much higher than betanidin level.