Natural Colorant from Marigold-Chemistry and Technology

Natural pigments offer an alternative to synthetic dyes, but for successful application, an understanding of the chemical and physical properties of the pigment is essential. With the growing legislative restrictions on the use of synthetic colors, a reappraisal of natural plant pigments is taking place with a view to use them as possible colorants in foods. For natural pigments to be accepted as food colorants, legal sanction is a must. With the application of new innovations, natural pigments can become more cost effective and increase their competitiveness against certified dye and dye products. Marigold flowers, which are yellow to orange red in color, are a rich source of lutein, a carotenoid pigment. This pigment has acquired greater significance because of its antioxidant property and for its eye health protection. Although marigold flower extract has been used in veterinary feeds, the potential use of marigold as a natural food colorant has not been exploited to the full extent due to the lack of information on its safety, stability, and compatibility in foods. This article deals with the chemistry, processing, and stability of the pigment and its applications.     

虾青素的应用及其商业化生产

虾青素是一种氧化胡萝卜素,作为着色剂在水产养殖和家禽养殖行业已经得到广泛的应用。同时由于虾青素超强的抗氧化作用,作为医药保健品也具有巨大的市场潜力。目前市场上的虾青素主要是人工合成的产品,利用微藻生产虾青素还存在一些技术上的问题。但是随着人们对天然产品的逐步认可和微藻生物技术的不断进步,大规模培养红球藻商业化生产天然虾青素是一种很有开发前景的产业。     

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.     

Pigment production by a new thermotolerant microalga Coelastrella sp. F50

Microalgae are good crops to produce natural pigments because of their high growth rates. Tropical zones are better locations than temperate areas for microalgal cultivation because they have longer duration of daylight and more stable temperatures throughout the year, but the high temperatures pose a challenge to microalgal cultivation. A newly isolated thermotolerant microalga produces reddish pigments under environmental stress. Morphological and molecular evidence including meridional ribs on the cell wall, pigment production, and its 18S rDNA sequence suggests that this microalga belongs to the genus Coelastrella. Salt stress and high light intensity accelerated biosynthesis of the pigments, and significant quantities of oil accumulated as the cells experienced stress due to nutrient deficiency. This microalga could withstand temperature of 50 °C for more than 8 h, which is a necessary trait for outdoor cultivation in tropical areas. The pigments contain astaxanthin, lutein, canthaxanthin, and β-carotene as analysed by using HPLC.     

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.     

Production of Red Water-Soluble Monascus Pigments

Water-soluble and thermal, as well as photo-stable, red Monascus pigments, were prepared by reacting the extracted pigment with aminoacetic acid and aminobenzoic acid. These modified pigments were compared to those using glutamic acid and gelatin as the modifying agents, showing that the colors and stabilities of these modified pigments were similar. Red pigments extracted from the mycelia could be dissolved in ethanol, propylene glycol, or in gelatin solution and freeze-dried. These red pigment concentrates or freeze-dried pigments could also be used as food colorants.     

Commercial applications of microalgae

The first use of microalgae by humans dates back 2000 years to the Chinese, who used Nostoc to survive during famine. However, microalgal biotechnology only really began to develop in the middle of the last century. Nowadays, there are numerous commercial applications of microalgae. For example, (i) microalgae can be used to enhance the nutritional value of food and animal feed owing to their chemical composition, (ii) they play a crucial role in aquaculture and (iii) they can be incorporated into cosmetics. Moreover, they are cultivated as a source of highly valuable molecules. For example, polyunsaturated fatty acid oils are added to infant formulas and nutritional supplements and pigments are important as natural dyes. Stable isotope biochemicals help in structural determination and metabolic studies. Future research should focus on the improvement of production systems and the genetic modification of strains. Microalgal products would in that way become even more diversified and economically competitive.     

Enhancing production of microalgal biopigments through metabolic and genetic engineering

Abstract

The versatile use of biopigments in food, feed, cosmetic, pharmaceutical and analytical industries emphasized to find different and renewable sources of biopigments. Microalgae, including cyanobacteria, are becoming a potential candidate for pigment production as these have fast-growing ability, high pigment content, highly variable and also have “Generally recognized as safe” status. These algal groups are known to produce different metabolites that include hormones, vitamins, biopolythene and biochemicals. We discuss here the potential use of microalgal biopigments in our daily life as well as in food and cosmetic industries. Pigment like carotenoids has many health benefits such as antioxidant, anti-inflammatory properties and also provide photo-protection against UV radiation. This review details the effect of various abiotic and biotic factors such as temperature, light, nutrition on maximizing the pigment content in the microalgal cell. This review also highlights the potential of microalgae, whether in present native or engineered strain including the many metabolic strategies which are used or can be used to produce a higher amount of these valuable biopigments. Additionally, future challenges in the context of pigment production have also been discussed.     

微藻生物活性物质在食品工业中的应用进展

微藻能产多种生物活性物质,其中一些可以作为功能性食品的添加剂。一些微藻能积累大量人体所需的超长链不饱和脂肪酸,包括花生四烯酸(ARA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)。尽管利用微藻生产DHA技术已得到商业化应用,其他超长链不饱和脂肪酸仍尚不能通过微藻商业化生产。微藻中的多糖是微藻的细胞结构成分、储能物质或充当其他生理功能,它们通常具有粘弹性等流变特性,因此它们不仅可以作为保健食品的功能因子,还适合作果冻和饮料的配料。类胡萝卜素、藻胆蛋白和叶绿素等色素,具有生物活性,可作为具有保健作用的食品着色剂。一些微藻类胡萝卜素已经能够商业化生产,但是像叶绿素等其他微藻色素的工业化生产技术仍待开发。微藻还能合成多种具有抗病毒、抗氧化和血管紧张素转换酶抑制活性的肽,一些生物活性肽也可通过水解微藻蛋白获得。本文综述了微藻的生物活性物质以及这些活性成分在功能性食品中应用的可能性。     

Growth dilution of metals in microalgal biofilms

Despite the key role microalgae play in introducing toxicants into aquatic food webs, little is known about the effects of environmental factors on metal accumulation by these primary producers. Environmental factors such as light and nutrients alter growth rates and may consequently influence metal concentrations in microalgae through growth dilution. Laboratory experiments suggested that metal uptake and elimination by microalgal biofilms were gradual enough to enable dilution of metals within the biofilms by photosynthetically accrued carbon, and a simple kinetic model of metal accumulation predicted significant variation in metal content due to growth dilution over the natural range of microalgal growth rates. The ratio of metal uptake to carbon uptake by microalgal biofilms decreased exponentially with increasing light in short-term laboratory experiments because photosynthesis was much more sensitive to a light gradient than was metal uptake. The effect of light on biofilm metal concentrations was confirmed in situ with a long-term experiment in which experimental shading of biofilms in a metal-contaminated stream decreased biofilm growth rates and caused a 3x increase in biofilm concentrations of twelve metals, including methylmercury. Slow growth at the primary producer level is a likely contributor to higher biotic metal concentrations in shaded, oligotrophic, or cold ecosystems.     

不同光照、氮源对Serratia marcescens y2生长、产色素的影响

为研究Serratia marcescens y2产生灵菌红素的条件,用固体培养和分光光度法研究不同光照(白光照、黑暗;红、黄、蓝和绿光)、氮源(氯化铵、甘氨酸、硝酸钾、尿素、水解乳蛋白和酵母膏)对细菌生长量和色素产生的影响。结果表明：黑暗培养有利于细菌生长和色素产生;单色光中绿光照射细菌生长量最小,伴有较多色素溢出胞外,色素被氧化程度高,反之红光对生长量影响最小,色素溢出率最低,色素被氧化程度低,说明该菌产红色素吸收绿光最多,光氧化损伤细胞导致色素外溢。氮源中有机氮源均促进细菌生长,除酵母膏外有机氮均增加了细菌色素生产量,其中甘氨酸效果最好,与无机氮源相比,甘氨酸还促使该菌产生不同色素成分,说明甘氨酸能改变色素合成途径,促进色素产量和不同结构色素积累。     

Chlorella vulgarisused to Colour Egg Yolk

Dry biomass obtained from stressed cells of Chlorella vulgaris (rich in carotenoid pigments) was used as such in animal feed, instead of the commercial synthetic pigment. The in vivo effect of microalgal biomass as substitute pigment was ascertained with Hisex brown hens kept laying during 37 days under conventional conditions, and strongly suggested that yolk pigmentation was comparable to that obtained using commercial pigments, when comparable weight of colourant was formulated into the feed.     

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.     

食用色素对淀粉着色力的估计

使用食品中发现的典型合成色素,配制适当浓度产色;用其中的胭脂红、柠檬黄与靛兰分别对淀粉液染色,颜色量度为亨特L、a、b值,并作图,以确定颜色在该色体中的可接受范围。此模型体系可用于估计着色剂的着色以及在食品中的用量。 我们假定着色力为色素浓度与色差之比,讨论其值与色素浓度的关系。     

花青素的提取、分离以及纯化方法研究进展

花青素是一种存在于自然界的水溶性多酚类化合物,现已发现其具有多种功能。有关花青素的提取、分离和纯化研究报道很多,文中就近年来国内外相关方面的研究进展进行了分析。     

微藻色素的研究进展

色素作为一种着色剂,广泛应用在食品、纺织和医药等领域。本文对微藻类天然色素,尤其是已经成功进入市场或将来有很大应用前景的微藻类天然色素的研究状况,包括其物理、化学、生物学性质以及生产工艺优化进行概述,并对微藻天然色素的未来发展趋势和应用前景进行预测。     

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.     

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.     

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。     

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.