Natural Colorants:Historical,Processing and Sustainable Prospects

With the public’s mature demand in recent times pressurized the textile industry for use of natural colorants,without any harmful effects on environment and aquatic ecosystem,and with more developed functionalities simultaneously.Advanced developments for the natural bio-resources and their sustainable use for multifunctional clothing are gaining pace now.Present review highlights historical overview of natural colorants,classification and predominantly processing of colorants from sources,application on textiles surfaces with the functionalities provided by them.Chemistry of natural colorants on textiles also discussed with relevance to adsorption isotherms and kinetic models for dyeing of textiles.

Analysis of Genetic Polymorphic SSR Markers in Germplasm Resources of the Natural Colored Cotton

Short sequence repeats(microsatellite,SSR) and expressed sequence tags-SSR(EST-SSR) markers were employed to analyze the genetic diversity of natural colored cotton varieties.About

Genetic Linkage Analysis of the Natural Colored Fiber and Fuzzless Traits in Cotton

Genetic linkage relationship of the natural colored fiber and six fuzzless seed germplasms in obsolete backgrounds of Gossypium hirsutum(AD genome) and G.barbadense were analyzed in the

Flavanone and flavonoid hydroxylase genes regulate fiber color formation in naturally colored cotton

Using naturally colored cotton(NCC)can eliminate dyeing,printing and industrial processing,and reduce sewage discharge and energy consumption.Proanthocyanidins(PAs),the primary coloration components in brown fibers,are polyphenols formed by oligomers or polymers of flavan-3-ol units derived from anthocyanidins.Three essential structural genes for flavanone and flavonoid hydroxylation encoding flavanone-3-hydroxylase(F3H),flavonoid 3’-hydroxylase(F3’H)and flavonoid 3’5’-hydroxylase(F3’5’H)are initially committed in the flavonoid biosynthesis pathway to produce common precursors.The three genes were all expressed predominantly in developing fibers of NCCs,and their expression patterns varied temporally and spatially among NCC varieties.In GhF3Hi,GhF3’Hi and GhF3’5’Hi silenced lines of NCC varieties XC20 and ZX1,the expression level of the three genes decreased in developing cotton fiber,negatively correlated with anthocyanidin content and fiber color depth.Fiber color depth and type in RNAi lines changed with endogenous gene silencing efficiency and expression pattern,the three hydroxylase genes functioned in fiber color formation.GhF3H showed functional differentiation among NCC varieties and GhF3’H acted in the accumulation of anthocyanin in fiber.Compared with GhF3’H,GhF3’5’H was expressed more highly in brown fiber with a longer duration of expression and caused lighter color of fibers in GhF3’5’H silenced lines.These three genes regulating fiber color depth and type could be used to improve these traits by genetic manipulation.

Natural hydroxyanthraquinoid pigments as potent food grade colorants:an overview

Natural pigments and colorants are widely used in the world in many industries such as textile dying,food processing or cosmetic manufacturing.Among the natural products of interest are various compounds belonging to carotenoids,anthocyanins,chlorophylls,melanins,betalains...The review emphasizes pigments with anthraquinoid skeleton and gives an overview on hydroxyanthraquinoids described in Nature,the first one ever published.Trends in consumption,production and regulation of natural food grade colorants are given,in the current global market.The second part focuses on the description of the chemical structures of the main anthraquinoid colouring compounds,their properties and their biosynthetic pathways.Main natural sources of such pigments are summarized,followed by discussion about toxicity and carcinogenicity observed in some cases.As a conclusion,current industrial applications of natural hydroxyanthraquinoids are described with two examples,carminic acid from an insect and Arpink red^(™)from a filamentous fungus.

The feasibility study of natural pigments as food colorants and seasonings pigments safety on dried tofu coloring

In order to improve appetite,attract consumers and even conform to the food culture,food coloring has become one of the necessary links in modern food processing.For example,dried-tofu will be colored by adding artificial food colors(AFCs)such as sunset yellow,cochineal red A or other seasonings like soy sauce.However,the dispute persists about whether AFCs are harmful to health.Some studies indicate AFCs affect children’s intelligence and attention,cause hyperactivity,and allergy when children consumed≥50 mg.In addition,researches showed that chemical soy sauce produces a trace of methylglyoxal(MGO)in the manufacturing process,which is related to diseases such as oxidative stress,diabetes,and cognitive deterioration.Therefore,natural pigments are relatively new and promising strategy for replacing high-risk AFCs.Thus,the objective of this study was to use dried-tofu as a natural colorants coloring screening platform,through the concept of three primary colors to discuss the coloring effects of natural colorants in Taiwan in double–phase(liquid phase to solid phase)food coloring system and assess the effects of MGO on PC12 neuron cellular morphology and cell cycle at the dietary exposure in soy sauce.Our results showed that formula G:R=0.2:0.8 and C:R=0.08:0.92 were coloring by combined natural colorants had the same eye sensory quality acceptance of consumer and had the intention to purchase.Furthermore,the results from the PC12 cell suggested that dietary exposure of methylglyoxal(<50M)in soy sauce did not affect neuron cellular morphology and cell cycle significantly.Overall,Gardenia Yellow,Curcumin,and Radish Red could overcome the application restrictions in multiplephase food coloring system and simultaneously soy sauce as a coloring agent was safety.It showed the possibility of them as food colorants on dried-tofu.

Study on the Genetics and Development of Fiber Pigments and Color Deviation After Wetting Process of Naturally Colored Cotton

The genetic control of fiber pigment color in naturally colored cotton was studied. The expression of brown and green fiber color was controlled by incompletely dominant single genes and incompletely dominant major genes, respectively. Production and accumulation of the fiber pigment were related to special expression of enzymatic genes for pigment synthesis in fiber cells. At the stage of fiber lengthening, naturally colored cotton, like white cotton, appeared purely white. But when fiber cell walls entered the thickening stage, pigment appeared by degrees. When the fiber was completely matured (on boll dehiscence), the color reached its darkest level. After wetting process treatment, the hues of the fiber pigment changed in regular patterns. The hue circle for brown and green cotton changed in the opposite direction with wetting process treatment. In general, the treated cotton color and luster became dark and vivid, and this trend provided the possibility for enhancing the fiber quality by suitable environmental friendly finishing. The analysis showed that the color and luster of the cotton may be controlled by a series of pigments which show different chemical performance.

Towards natural object-based image recoloring

Existing color editing algorithms enable users to edit the colors in an image according to their own aesthetics.Unlike artists who have an accurate grasp of color,ordinary users are inexperienced in color selection and matching,and allowing non-professional users to edit colors arbitrarily may lead to unrealistic editing results.To address this issue,we introduce a palette-based approach for realistic object-level image recoloring.Our data-driven approach consists of an offline learning part that learns the color distributions for different objects in the real world,and an online recoloring part that first recognizes the object category,and then recommends appropriate realistic candidate colors learned in the offline step for that category.We also provide an intuitive user interface for efficient color manipulation.After color selection,image matting is performed to ensure smoothness of the object boundary.Comprehensive evaluation on various color editing examples demonstrates that our approach outperforms existing state-of-the-art color editing algorithms.