Changes in color of calcium enriched apple slices irradiated with UV-C light.

GÓMEZ, PAULA; SALVATORI, D.; ALZAMORA, S.

Chicago, IL.

Congreso; The 2010 Institute of Food Technologists Annual Meeting (IFT).; 2010

Institute of Food Technologists

In the last years there has been a growing interest in designing functional foods using vegetable matrices impregnated with bioactive components. Previous studies have demonstrated the feasibility of incorporation of calcium in fresh fruit matrices by impregnation processes. The development of these products of high humidity requires the application of appropriate conservation technologies to ensure microbiological safety during storage without compromising quality. Shortwave ultraviolet light (UV-C) is an emerging technology that can be used to extend the shelf life of these products. The objective of this work was to study color changes in calcium enriched apple slices irradiated with UV-C light and to evaluate the use of an antibrowning pretreatment in order to minimize enzymatic browning during refrigerated storage. Apple slices (3 cm diameter, 0.6 cm thickness) were impregnated at atmospheric pressure in aqueous solutions containing 12.6 % w/w glucose and 5.4 % w/w calcium salts. Prior to impregnation, samples were treated with an antibrowning solution (1% w/v ascorbic acid + 0.1 w/v calcium chloride). For UV-C irradiation, slices were placed at 10 cm distance from two germicidal lamps (253.7 nm, 15 W) at different exposure times (2-20 min) (UV-C dose: 1-11 kJ/m2). Impregnated and irradiated samples (with or without immersion in antibrowning solution) were compared to a control (fresh apple) throughout storage (a week at 4-5ºC). At selected intervals (0, 3 and 7 days), tristimulus color measurements were made on ten treated samples for each condition. Apple slices impregnated with calcium and irradiated with UV-C light showed a significant increase in surface browning during storage (slightly higher as UV-C dose increased) as compared with control and only irradiated fruit. The antibrowning pretreatment was effective to reduce browning. Changes in color of apple slices caused by calcium impregnation process and UV-C radiation can be minimized applying a suitable antibrownig pretreatment.