Pigment changes in spinach-added fried products during storage under dark

초록

Chlorophyll and carotenoids contents changes in spinach (Spinacia oleracea) powder added (5, 15 or 25%) fried products during storage at 60℃ under dark were determined by high performance liquid chromatography and spectrophotometry after the separation by column chromatography, respectively. Dough with weak flour, freeze-dried spinach powder (5, 15 and 25%) and distilled water was sheeted at 0.1 cm thickness and then was cut to a square (2×2 cm) shape before frying. Frying was performed in soybean oil at 160℃ for 1 min and repeated every 20 min for 2 h. Fried samples were put in a glass serum bottle and the bottles were tightly sealed with teflon-coated septa and aluminum caps. The bottles were covered with aluminum foil and stored in a 60℃ incubator for 12 days. Fried samples contained chlorophylls (a and b), pheophytins (a and b), carotenes, monohydroxy carotenoids, dihydroxy carotenoids including lutein and other carotenoids. Chlorophylls, carotenes and monohydroxy carotenoids were the major parts. Contents of pigments in the spinach powder added fried products decreased with storage time and carotenoids were much more stable than chlorophylls. Chlorophyll a was completely disappeared after 2 day storage, however, about 50% of chlorophyll b was still remaind, indicating that chlorophyll b was more stable than chlorophyll a during storage under dark. Contents of pheophytins in the fried products increased and then remained relatively constant with storage time. These results suggested that chlorophylls were converted to pheophytins during storage and pheophytins were much more stable than chlorophylls. Decrease in carotene contents with storage time was lower than that in monohydroxy or dihydroxy carotenoids. This indicates that carotenes were the most stable among carotenoids present in spinach during 12 day storage and they can exert a role of antioxidants to improve storage stability of the fried products.