Study on the Effect of the Different Heating Processes on the Quality of the Chinese Date

The amount of water, carbohydrate and vitamin C in a Chinese date dried in three different ways were measured quantitatively. Particularly the content of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in the ethyl ether abstract from the same samples were determined by gas chromatography. The following three drying ways were utilized to bake Chinese dates: 1)to increase the temperature of the stove slowly to 55～60℃ during 6～8 hours, then to 68～70 ℃ during 8～10 hours, finally, to decrease temperature to 50 ℃ during 6 hours, the total baking time is 24 hours; 2) to increase the temperature of the stove slowly to 55～60 ℃ during 5～6 hours, then to keep this temperature for 10 hours and finally to decrease temperature to 50℃ during 3～4 hours, the total baking time is 20 hours; 3) to increase the temperature of the stove quickly to 65～68 ℃ during 3～4 hours, then to keep this temperature for 5～6 hours, finally, to decrease temperature to 50 ℃ during 5～6 hours, the total baking time is 18 hours, the quality of the date dried by the first way and the second is better than that by the third way. The formation, measurement of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in date and their influences on the dry date were discussed.