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Colorants, Pigments, and Dyes
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Iron oxide (Fe2O3) red is technologically an important pigment and has superior character in non-toxicity, chemical stability, and durability and low costs. It is widely applied as pigments in the building industry, inorganic dyes, ceramics, and adsorbents in the paper industry, lacquers or plastics. Natural iron oxides are derived from hematite, which is a red iron oxide mineral; limonites, which vary from yellow to brown, such as ochers, siennas, and umbers; and magnetite, which is black iron oxide. Synthetic iron oxide pigments are produced from basic chemicals. The three major methods for the manufacture of synthetic iron oxides are thermal decomposition of iron salts or iron compounds, precipitation of iron salts usually accompanied by oxidation, and reduction of organic compounds by iron. Lately, the synthesis of nano-iron red oxide pigment by cyanided tailings via ammonia process with urea has been published. The particle size of iron oxide crystal prepared on different temperature and pH conditions showed different color shades (Dengxin et al., 2008).
Preparation of iron-loaded water-in-oil-in-water (W1/O/W2) double emulsions: optimization using response surface methodology
Published in Journal of Dispersion Science and Technology, 2023
Shima Saffarionpour, Levente L. Diosady
Iron plays an indispensable role in myoglobin and hemoglobin formation and transport of oxygen in the human body. Low intake and bioavailability of this mineral are the main causes of iron deficiency anemia in industrialized countries.[1] In addition, in developing countries of Africa, South, and Southeast Asia, such as Maldives, India, and Myanmar,[2] the consumption of polyphenol-rich vegetables such as beans,[3] peppermint, and turmeric[4] with iron-chelating properties, and beverages such as tea,[5] can play a major role in the inhibition of iron absorption. To increase the intake of this micronutrient and overcome the problem of iron deficiency, fortification or enrichment of foods through addition of various iron sources is being considered worldwide.[6,7] The iron sources used for food fortification are classified into (i) water-soluble iron compounds such as ferrous sulfate, ferrous gluconate, ferric ammonium citrate, and ferrous ammonium sulfate. (ii) Iron compounds with poor water solubility that are soluble in dilute acids, such as ferrous fumarate, and ferrous succinate. (iii) Iron compounds that are insoluble in water and poorly soluble in dilute acids such as ferric pyrophosphate and ferric orthophosphate. (iv) Other iron sources such as ferric sodium EDTA. Iron compounds are selected for fortification based on their bioavailability, cost, and organoleptic properties. While water-soluble iron sources show high bioavailability, they contribute to an undesired change in color or taste of the food product. Conversely, the water-insoluble iron types that are organoleptically inert, do not influence the color and taste of the food product, but are less bioavailable.[8] Ferric sodium EDTA is an iron source that is 2–3 times more bioavailable than other iron sources such as ferrous sulfate since it prevents binding of iron to phytates[9] and can be efficiently incorporated into hemoglobin. Through consumption of foods fortified with this iron compound an additional iron uptake of 2.2 mg/day for children and 4.8 mg/day for male adults can be achieved.[10] Ferric sodium EDTA had fewer side-effects such as gastrointestinal problems and produced no metallic taste.