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Reaction Kinetics in Food Systems
Published in Dennis R. Heldman, Daryl B. Lund, Cristina M. Sabliov, Handbook of Food Engineering, 2018
Ricardo Villota, James G. Hawkes
Color remains to be one of the first single most notable characteristics of food that often predetermines a consumer’s judgement on food quality (Spence, 2016), so, obviously, color stability is still an extremely important factor in foods. Over a decade ago, Griffiths (2005) reviewed acceptable synthetic and natural colors used in the US food industry and indicated a trend for an increased use of colors particularly in novelty snacks, desserts, and beverages, further emphasizing the importance of color stability in foods; this trend continues today, but mostly in the direction of natural colors. With increased awareness over health and safety concerns over synthetic food colorants and their potential toxicity, greater emphasis is being placed on more natural alternatives to meet consumer expectations (Amchova et al., 2015; Martins et al., 2016). Wrolstad and Culver (2012) more recently reviewed alternatives to artificial colors, and as new natural colorants have become more available, the numbers of acceptable color ingredients has been in constant flux; Table 3.4 presents natural colors approved for use in food in the US as of November 2017 (US FDA, 2017). Based on the US Code of Federal Regulations (CFR), natural colorant replacements must meet targets for hue, stability in specific application, and cost. These are rigid criteria to fall under as natural colors hardly ever meet the intensity of artificial dyes requiring significantly higher concentrations and creating potential off-flavors, increased cost, and decreased stability. Colorants such as carotenoids including β-carotene, annatto, paprika, and particularly lycopene are known to exhibit antioxidant activity. Flavonoids, including the anthocyanin group, have also been attributed to having health benefits such as antioxidant properties, anti-inflammatory effects, lowered blood pressure, and anti-tumor properties. Another group of colorants, known as the curcuminoids found in turmeric, are also found to have similar health-related properties as well as antithrombic effects and antimicrobial activity (Taylor, 1996). More recently, a new group of natural blue colors, phycocyanins, have been approved for use as colorants in certain types of foods and have potential health benefits as well as aesthetic appeal; they have been reported to have nutritional and antioxidant benefits (Eriksen, 2008). Overall changes in color may be due to a number of reactions such as pigment degradation or polymerization, interaction with other components in the food product, non-enzymatic browning, oxidation of tannins, and other reactions. The following section discusses some of the major sources of color pigments that are naturally present or added to processed foods and their relative stability to processing and/or storage conditions.
Adsorption of natural annatto dye by kaolin: kinetic and equilibrium
Published in Environmental Technology, 2020
Munique Dias, Alexsandra Valério, Débora de Oliveira, Antônio A. Ulson de Souza, Selene M. Guelli U. de Souza
Bixa Orellana, a tree from Bixaceae family, is native from Central and South America and widespread in the tropics [1,37]. Annatto is an orange-red dye structured by carotenoid with two carboxylic acid groups, one of which is a mono-ester is the main component of the annatto, derived from the seeds of B. orellana L. [38,39]. It is widely used in industry, cosmetics, and pharmaceutical products and as a food colouring and textile dye, and as many natural dye, annatto is susceptible to oxidative degradation and the loss of colour occurs after prolonged exposure to light and/or elevated temperatures [40,41]. The relatively low production cost and low toxicity provides a very attractive natural dye to replace synthetics [18], and due to the photoactive properties was recently explored as a sensitizing dye in solar cells and for photodynamic therapy [39,42,43].