Chapter 13
Inhibition of Citral Deterioration 1
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Hideki Masuda , Toshio Ueno , Shuichi Muranishi , Susumu Irisawa , and Chi-Tang Ho Downloaded by COLUMBIA UNIV on April 19, 2015 | http://pubs.acs.org Publication Date: March 4, 2002 | doi: 10.1021/bk-2002-0807.ch013
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Material R&D Laboratories, Ogawa & Company, Ltd., 15-7, Chidori, Urayasushi, Chiba 279-0032, Japan Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520
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Citral is a very important component of lemon flavor. However, citral is liable to be deteriorated by contact with various agents including light, heat, oxygen, and acid. Therefore, the inhibition of deterioration of citral is considered to be an important problem for the stabilization of citrus drinks. For the purpose of inhibiting the deterioration of citral during UV light irradiation under acidic conditions, the ability of UV light absorption and the radical scavenging activity of a variety of additive compounds are studied.
Citral is well-known as the most characteristic component of lemon flavor. The value of citrus drinks containing lemon flavor is dependent on the stability of citral (/). However, citral is deteriorated through acid-catalyzed or oxidation mechanisms (2-7). The potent off-flavor components formed from citral under acidic and heated conditions have been clarified by aroma extract dilution analysis (AEDA) (8). In recent years, longer storage times and displays using transparent containers under fluorescent lamps in stores have significantly increased and citral is easily deteriorated by UV lightfromfluorescentlamps.
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© 2002 American Chemical Society In Free Radicals in Food; Morello, M., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002.
Downloaded by COLUMBIA UNIV on April 19, 2015 | http://pubs.acs.org Publication Date: March 4, 2002 | doi: 10.1021/bk-2002-0807.ch013
177 The off-flavor components of citral due to UV light or sunlight have also been studied (9-14). Taking into account the instability of citral, it is important for many flavor and food companies to use food additives which inhibit the deterioration of citral. However, the relationship between the stability of citral and the kinds of additive compounds inhibiting its deterioration has scarcely been reported (ISIS). In addition, in spite of the wide use of ascorbic acid, the degraded components derived from it can lower the value of a citrus drink (19-21). Therefore, it was necessary to find effective additive compounds that inhibit the deterioration of citral. This study focuses on the effects of the additive compounds on both the stabilization of citral and the reduction of reaction products derived from citral due to UV light.
Experimental 0.1 g of 1% (w/w) solution of each additive compound prepared by dissolving in 50% (w/w) ethanol, was mixed with a 0.1 M citric acid-sodium citrate buffer (99.9 g, pH 3.5 or 7.0) containing 10000 ppb citral. Therefore, the concentration of additive compound in each solution was 10000 ppb. The glass bottle was irradiated at 10°C in a Eyela LST-300 light box with an fluorescent lamp consisting of 3 wavelength-type 40 W>
