Availability and Utilization of Pigments from Microalgae

Microalgae are the major photosynthesizers on earth and produce important pigments that include chlorophyll a, b and c, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins. Presently, synthetic colorants are used in food, cosmetic, nutraceutical, and pharmaceutical industries. However, due to problems associated with the harmful effects of synthetic colorants, exploitation of microalgal pigments as a source of natural colors becomes an attractive option. There are various factors such as nutrient availability, salinity, pH, temperature, light wavelength, and light intensity that affect pigment production in microalgae. This paper reviews the availability and characteristics of microalgal pigments, factors affecting pigment production, and the application of pigments produced from microalgae. The potential of microalgal pigments as a source of natural colors is enormous as an alternative to synthetic coloring agents, which has limited applications due to regulatory practice for health reasons.     

Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications

The production of natural food pigments continues to grow worldwide. The global market is expected to grow at a compound annual growth rate of 6.22%, by revenue, over the period 2015 to 2019. Pigments such as anthocyanins, carotenoids, betalains, and chlorophylls have been used to color foods. However, there are challenges related to color losses during food processing, storage, and commercialization due to a low stability of natural pigments compared to synthetic colorants. This review summarizes the most recent studies and patents aimed at enhancing anthocyanin stability in food systems. The stabilizing methods include additions of copigment compounds, such as polymers, phenolic compounds, and metals. In addition, the exclusion of O₂ during processing and storage, hard‐panned candy coating methods for blue, green, and brown colors, and various encapsulation techniques were considered. Combining strategies and evaluating new materials capable of stabilizing anthocyanins will enhance their potential for use as value‐added natural food pigments.     

Betalain Stability and Degradation—Structural and Chromatic Aspects

ABSTRACT:  In recent years, food coloring with artificial colorants has been increasingly disapproved by consumers. In return, application of coloring foodstuffs, among them betalain-containing fruits and vegetables, has gained importance for the food industry. As commonly true for natural pigments, betalains are afflicted with inferior stability compared to synthetic dyes. Especially temperature, oxygen, and light are known to exhibit detrimental effects on betalain integrity, while certain antioxidants and chelating agents may act as stabilizers. Only recently, several studies expanded the knowledge on betalain degradation pathways, especially focusing on betacyanin decomposition. Additionally, new findings on stability and stabilization of betalains in cactus fruit juices extended the application range of betalainic foodstuffs. Focusing on betacyanins, the present review discusses betalain degradation mechanisms and provides a survey of compounds and conditions governing betalain stability in a beneficial or an unfavorable way. Finally, strategies for maintaining the chromatic properties and tinctorial strength of betalain-based juices and pigment preparations as well as tools for color modulation by targeted betacyanin degradation are discussed.     

食品中着色剂的检测方法研究进展

着色剂是食品添加剂中的一大类分支,在食品加工和生产中有着广泛的应用。由于食品的基质类型复杂多样,着色剂的种类也非常多、性质差异大,给分析检测工作带来挑战。本文对近年来的食品中着色剂的检测方法进行综述,包括样品前处理和分析检测技术,并根据应用方法和适用的食品基质及检测目标物进行分类总结,为进一步开展食品中着色剂的检测方法的研究工作提供参考。     

红枣红色素的研究进展

随着食品工业的迅猛发展,食品添加剂在人们生活中发挥的作用日益显著。近年来,食品安全屡遭质疑,人们对食用色素也提出了更高的要求,相较于大多数具有致癌风险的合成色素,取自天然、无污染的植物色素更受到人们的青睐。枣红色素是一种提取自红枣果皮的天然色素资源,但开发和利用这一天然色素资源还存在许多问题。本文就色素组成、性质、药理活性、提取和精制方法及深加工技术进行了介绍,综述了近年来红枣红色素在提取、加工和应用方面的研究概况。分析表明,红枣红色素原料来源丰富,提取方便,是一种值得深度开发的性能优异的天然色素资源,但在色素结构鉴定、高效低能耗提取方法开发和产品干燥制粉等方面目前开展的工作较少,文末就此对枣红色素的研究进行了展望。     

天然花色苷色素稳定化研究进展

文章综述了近些年花色苷的保护技术,包括添加大分子物质、小分子辅色、金属离子螯合和包埋技术等,指出未来需要进一步加强新技术、新材料在花色苷保护方面的应用,以及针对不同种类食品体系专属定制稳定化方法的研究开发。     

Valorisation of food wastes to produce natural pigments using non-thermal novel extraction methods: a review

Waste or by-products produced during food processing can be used as a potential source of bioactive compounds including natural pigments. Natural pigments/colourants have numerous health benefits whereas the synthetic colourants have many negative effects on human health. Thus, there is a considerable interest worldwide in pigments extraction from natural sources. Conventional extractions such as soxhlet extraction, water distillation, and solvent extraction have many limitations such as large solvent consumption, long extraction time, and low extraction yields. Therefore, novel techniques such as high pressure, ultrasound, negative pressure and electric field have been employed to assist the pigment extraction process. The novel extraction methods are being developed with the primary aim of higher pigment yield, lower solvent consumption, minimised environmental effects and the convenience of extraction. With this perspective, the present review provides recent insights into the recovery of natural pigments from food wastes/by-products and the application of novel non-thermal technologies for their recovery.     

花色苷稳定化途径及自聚合效应研究进展

花色苷作为一种天然食用色素,安全无毒,被认为是替代合成食用红色素的最理想的天然色素。但花色苷稳定性差,限制了其在食品领域中的应用。主要介绍了花色苷的种类、结构及变化和改善花色苷稳定性的方法,同时重点阐述了花色苷自聚合作用的发生机制、检测指标及利用现状等,并对花色苷的应用前景进行了展望。     

Anthocyanin Pigments—Bioactivity and Coloring Properties

ABSTRACT: Anthocyanin pigments are responsible for the attractive red to purple to blue colors of many fruits, vegetables, flowers, and cereal grains. In plants they serve as attractants for pollination and seed dispersal, give protection against the harmful effects of UV irradiation, and provide antiviral and antimicrobial activities. Anthocyanin-based colorants are commercially manufactured for food use from horticultural crops and from processing wastes. There is a large body of knowledge on anthocyanin chemistry in the literature that includes established, systematic methods for identifying anthocyanins and measuring their concentration and color properties. Structural variation (B-ring substitution, glycosidic substitution, and acylation) produces a multiplicity (over 400) of anthocyanins. Color intensity and hue, as well as stability, are markedly affected by pH, which can be a major limitation for many food applications. Increased glycosidic substitution and acylation with cinnamic acids will improve pigment stability. However, the matrix in which the pigments exist can have a much greater impact on pigment degradation. Anthocyanin pigments are very effective scavengers of free radicals. Currently, there is much research activity on their possible health benefits. While anthocyanin-based colorants are universally approved for food use, there are considerable regulatory differences among countries.     

食品合成色素前处理中富集技术的研究进展

合成色素作为添加剂被广泛应用于食品中,但是合成色素的超范围添加和非法添加会给人体健康带来安全隐患,有必要对其含量进行检测。由于食品基质较为复杂,一般在进行分析检测前需要通过前处理进行样品的提取富集。本文主要对色素的传统富集方法包括液-液萃取和萃取柱萃取等研究进展进行介绍,并重点综述了新型材料在富集色素方面的应用,主要包括二维材料、有机金属框架及磁性复合材料,为合成色素检测前处理阶段吸附剂的选择提供了系统性知识,同时对未来合成色素吸附剂的发展进行展望。     

Ecological-friendly pigments from fungi

The dyestuff industry is suffering from the increases in costs of feedstock and energy for dye synthesis, and they are under increasing pressure to minimize the damage to the environment. The industries are continuously looking for cheaper, more environmentally friendly routes to existing dyes. The aim of this minireview is to discuss the most important advances in the fungal pigment area and its interest in biotechnological applications. Characteristic pigments are produced by a wide variety of fungi and the chemical composition of natural dyes are described. These pigments exhibit several biological activities besides cytotoxicity. The synthetic pigments authorized by the EC and in USA and the natural pigments available in the world market are discussed. The obstacle to the exploitation of new natural pigments sources is the food legislation, requesting costly toxicological research, manufacturing costs, and acceptance by consumers. The dislike for novel ingredients is likely to be the biggest impediment for expansion of the pigment list in the near future. If the necessary toxicological testing and the comparison with accepted pigments are made, the fungal pigments, could be acceptable by the current consumer. The potentiality of pigment production in Brazil is possible due to tremendous Amazonian region biodiversity.     

Stability Modeling of Red Pigments Produced by Monascus purpureus in Submerged Cultivations with Sugarcane Bagasse

Monascus purpureus red pigments were produced in submerged cultivations employing sugarcane bagasse (SB) as carbon source in combination with various nitrogen sources. Peptone and soy protein isolate (SPI) as nitrogen sources generated the best pigment yields. NH₄Cl has not supported high pigment production. Red pigments produced using SB and SPI as growth substrates were submitted to temperature and pH stability analysis. Data from thermal pigment degradation were fitted to five mathematical models, and a first-order equation was accepted as the best one to describe color decay. Red pigments showed high stability at low temperatures (30–60 °C) and at near-neutrality pH values (6.0–8.0) when compared to that at high temperatures (above 60 °C) and at acidic pH values (4.0–5.0). Monascus pigments produced using a low-cost agroindustrial waste (SB) as carbon source could be utilized as colorants in foods and foodstuffs manufactured under mild process conditions.     

Natural colorants: Pigment stability and extraction yield enhancement via utilization of appropriate pretreatment and extraction methods

Natural colorants from plant-based materials have gained increasing popularity due to health consciousness of consumers. Among the many steps involved in the production of natural colorants, pigment extraction is one of the most important. Soxhlet extraction, maceration, and hydrodistillation are conventional methods that have been widely used in industry and laboratory for such a purpose. Recently, various non-conventional methods, such as supercritical fluid extraction, pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, pulsed-electric field extraction, and enzyme-assisted extraction have emerged as alternatives to conventional methods due to the advantages of the former in terms of smaller solvent consumption, shorter extraction time, and more environment-friendliness. Prior to the extraction step, pretreatment of plant materials to enhance the stability of natural pigments is another important step that must be carefully taken care of. In this paper, a comprehensive review of appropriate pretreatment and extraction methods for chlorophylls, carotenoids, betalains, and anthocyanins, which are major classes of plant pigments, is provided by using pigment stability and extraction yield as assessment criteria.     

Fresh coffee husks as potential sources of anthocyanins

Fresh coffee husks, comprised of outer skin and pulp, were investigated as potential sources of anthocyanins for applications as natural food colorants. The extracted pigments were analysed by HPLC with photodiode array detection. Partial hydrolysis and analysis of the resulting fragments were helpful in the characterization procedure. Cyanidin 3-rutinoside was characterized as the dominant anthocyanin in fresh coffee husks and its quantification suggested the fresh coffee husks to be a good candidate as source of this pigment.     

藻类色素蛋的资源开发和应用研究

大海是一个宝库,蕴含着大量的海洋生物,其中各种颜色的藻类蕴含着丰富的蛋白质资源,是食品理想的蛋白源,但是人类目前所利用的仅为其中很少的一部分。作为藻类捕光色素的藻胆蛋白是藻类蛋白中的主要成分,是一种水溶性色素蛋白。藻胆蛋白所包含的藻红蛋白、藻蓝蛋白以及别藻蓝蛋白均具有一定的荧光特性,并分别呈现红色、蓝色和紫罗兰色的荧光,因此藻胆蛋白也是理想的天然色素添加剂。近年来由于合成色素添加剂所存在的一些隐患问题以及出现的一系列问题使得寻求天然色素添加剂尤为重要。而藻胆蛋白作为一种蛋白质同时又具有色素特征而深受食品加工业青睐,但是由于自身有一定的缺点,因此如何利用海藻色素蛋白是目前海藻加工业的一个热点问题,本文从藻胆蛋白的组成、光谱特性、稳定性和应用等方面进行简单论述。     

各国(地区)食用色素的使用现况与比对分析

食用色素分为焦油色素、天然色素和其他3类。按化学结构,食用焦油色素分为偶氮类、三芳基甲烷类、氧杂蒽类、荧光酮类、喹啉衍生物和靛系染料,天然色素分为四吡咯(卟啉类)衍生物、异戊二烯衍生物、花青苷类衍生物、酮类衍生物、醌类衍生物和其他类。食用色素的编码有INS、E-Number、CI以及部分国家(地区)对合成色素的代号。本文分类介绍了中国大陆、CAC、俄罗斯、欧盟、美国、加拿大、日本,以及中国香港、中国澳门和中国台湾10个国家(地区)的食用色素管理规定与允许使用品种。对各国(或地区)食品添加剂标准表述方式、禁止使用色素的规定、对焦油色素应用态度差异、允许使用色素(焦油色素、天然色素和其他类)品种的使用差异,以及食用色素使用范围与限量差别进行了比对分析,提出了我国出口食品生产应根据出口国(或地区)标准确定色素的使用,我国对进口食品应根据其来源确定重点关注色素品种与限量的建议,并分析了食用色素应用发展的趋势。     

天然色素研究与应用

天然色素不但具有呈色作用,并兼有营养、保健等功能,对人体健康起着重要保护作用。该文主要论谜天然色素特点与特性、分类、性质与作用、应用与开发。     

pH敏感性材料在智能食品包装中的应用进展

随着消费者食品安全意识的增强,通过包装颜色变化对食品品质进行直观判断成为一个新的需求,智能包装近年来成为学界和产业界的共同关注点。pH敏感性材料与聚合物混合后获得的食品包装膜,在不同的pH条件下显示不同颜色,具有实时监测肉、虾、牛奶等食品新鲜程度的效果。本文介绍了化学显色剂和天然色素显色剂两大pH敏感性型指示器,分类介绍花青素、姜黄素、茜素、紫草素、甜菜碱等天然食品色素在不同pH下的变色机理,总结了pH敏感性材料与不同聚合物共混改性后在食品包装领域的研究进展、应用现状和研究趋势,为制备性能良好、绿色环保的智能食品包装提供参考。     

生物质色素耐日晒色牢度提升的研究进展

生物质色素相比于合成染料具有天然、无毒、可再生、环境相容性好等优点,但其上染织物的耐日晒色牢度差限制了其使用。为实现生物质色素在纺织品染色领域大规模应用,以近年来国内外对生物质色素耐日晒色牢度研究为基础,总结目前常用于提升色素耐日晒色牢度的方法。从色素分子结构、新型媒染剂的选择以及有效光稳定剂的使用3个方面进行阐述,并对生物质色素的应用前景进行展望。     

Cancer cell antiproliferation activity and metabolism of black carrot anthocyanins

The antiproliferation activity of a black carrot anthocyanin-rich extract (BC-ARE) on human cancer cells (HT-29 colorectal adenocarcinoma and HL-60 promyelocytic leukaemia) and metabolism of its characteristic anthocyanins (acylated and nonacylated forms) in humans were investigated. Cancer cells were exposed for 24 h to 0.0–2.0 mg/mL of BC-ARE. Anthocyanin-rich extract inhibited proliferation of both types of cancer cells in a dose-dependent manner. After ingestion of a black carrot concentrate, three acylated and two nonacylated anthocyanins were excreted in the volunteers (n = 4) urine (0.048% of the administered dose). The anthocyanins were characterized by HPLC-DAD-ESI-MS/MS. Urine recovery of nonacylated anthocyanins was 8-fold higher than that of acylated anthocyanins.Industrial relevanceNatural pigments have achieved commercial significance as food colorants due to the fact that consumers perceive them as safe additives. At present extracts rich in acylated anthocyanins, which are known for their outstanding stability, serve as a major source of natural food colours for the food colorant industry with purple sweetpotato, red cabbage and black carrot being the major sources. Beside aesthetic values, anthocyanins possess enhanced physiological activity due to their potent antioxidant properties and enhance the health-promoting qualities of foods. Our findings on cancer cell antiproliferation activity of an anthocyanin-rich black carrot extract as well as information about the bioavailability of black carrot anthocyanins could lead to an increased application of these natural food colorants by the food industry.