UV-Blocking Film for Food Storage using Titanium Dioxide

TLDR: Hashimoto et al. as discussed by the authors developed a safe UV-blocking coating film using peroxo-modified anatase sol, which was produced by the heating of peroxotitanium acid solution.

Abstract: *To whom correspondence should be addressed. E-mail: a-hashimoto86253@pref.hiroshima.lg.jp Introduction In recent years, the irradiation exposure of foods to fluorescent light has shown an increasing tendency due to the extension of working hours in supermarkets and convenience stores. However, it is difficult to control food deterioration caused by UV light using conventional techniques (Cladman et al., 1998; Vassila et al., 2002; White, 1985). Common light-blocking films such as aluminized films maybe undesirable as packaging materials because they hide the food contents from customers. It is also possible that the migration of certain organic UV absorbers contained in UV-blocking films affects food safety (Pascall et al., 1995). For these reasons, the development of a safe and transparent UV-blocking film is currently required in the food industry (Fanelli et al., 1985; Irissin-Mangata et al., 2000; Schroder et al., 1985; Van Aardt et al., 2001). On the other hand, many organic or inorganic lightblocking materials for UV-blocking coatings have been developed for reconfiguring the substrate film surface (Fanta et al., 2002; Fayet et al., 1995; Hartwig, 1994; Hoffmann et al., 1994; Kelly, 1994; Lippens et al., 1998; Lohwasser et al., 1995; Schiller et al., 1996; Schiller et al., 1998; Schiller et al., 1999; Watanabe et al., 1997). Titanium dioxide has been used as a photocatalyst and UV-blocking agent and, according to the food sanitation law, is allowed as a food additive (e.g., white pigment). Titanium dioxide is also used in fields other than the food industry, for example as a colorant and UV-blocking agent in paint and cosmetics. Titanium alkoxide is a well-known raw material used in the preparation of titanium dioxide coatings on glass or metal surfaces. Titanium dioxide is generated by heating titanium alkoxide through the sol-gel process. Therefore, it is difficult to coat plastic film with titanium dioxide. Ichinose et al. (2001a; 2001b) reported on the preparation method of peroxotitanium acid solution by the addition of hydrogen peroxide solution to peroxotitanium dinuclear complex anions (Ti2O5(OH)x , x > 2). Peroxo-modified anatase sol was produced by the heating of peroxotitanium acid solution. The peroxo-modified anatase sol contained dispersed anatase crystallites (< 30 nm) in spite of its neutral pH. The sol is useful for coating plastic films because anatase titanium dioxide generates fine particles at room temperature. Photocatalytic activity appears on the plastic film surface by simply coating the plastic film with the sol. In the present study, we developed a safe UV-blocking coating film using peroxo-modified anatase sol.