Application of Lemon Oils Prepared by Different Extraction Methods to a Beverage and Stabilities to Sunlight

Abstract

We tried to elucidate the formation of off-flavor in 4 different lemon flavored beverages after sun-light irradiation. As a model, citral flavored beverage (pH 3 by citric acid) was prepared and was irradiated with sun-light for 1, 3, 8, 24 h. Five new peaks were detected on GC of the ether extract of the irradiated beverage. They were identified as photocitral A (1), photocitral B (2), epi-photocitral A (3), 2-(3-methyl-2-cyclopenten-1-y1) 2-methyl propionaldehyde (4), trans-1, 3, 3-trimethyl-bicyclo [3.1.0] hexane carboxaldehyde (5). The amount of compound 4 and 5 were far larger than that of other 3 compounds (1-3). Four kinds of acidic beverage flavored with 4 lemon oils (California In-line, Sicily In-line, Sicily Sfumatrice, and Sicily Pelatrice, C-I, S-I, S-S, S-P respectively) were prepared and were irradiated under the same condition as citral. The tendency of GC results of their ether extract were resembled to that of citral. The results of sensory evaluation gave following order : S-P_??_S-S>S-I>C-I. On the above panel results, the off-flavor depend on the amount of remained citral in lemon oils, not that of 5 compounds after irradiation. These results suggested that citral might mask the off-flavor. Hence, it was considered that the remained amount of citral affected the lemon note of lemon flavored beverage, and original citral amount in each lemon oils affected to the quality of beverages after sun-light irradiation. This conclusion indicated that extraction method of lemon (S-P, S-S, S-I) was important to keep its quality in beverages.