Effect of Hot-water Dipping on Inhibiting Red Discoloration of Basal Part in Chicon

초록

Hot water dipping test was conducted for chicon to restrict red discoloration of its basal part which impairs the product value during sales. Hot water dipping treatment was given to chicon for 4 min and for 8 min at 38 degrees C and for 2 min and 4 min at 42 degrees C, and for 1 min and 2 min at 45 degrees C, along with control (for one min at 20 degrees C). The red discoloration indices of basal part of chicon during sensory evaluation on the sixth day of storage under the storage temperature at 10 degrees C was lower at 42 degrees C for 2 min, 42 degrees C for 4 min and 45 degrees C for 1 min treatments. The color change value of the basal part in chicon measured by colorimeter showed that the lowest Delta a* and Delta h were maintained in the basal part of chicon treated at 42 degrees C for 2 mm. Whereas, color changes in 42 degrees C for 2 min and 45 degrees C for 1 min treatments were significantly low as compared with that of control. The contents of total phenolic compounds which are the substances that cause red discoloration of basal part in chicon were lowest at 42 degrees C for 2 min, 42 degrees C for 4 min and 45 degrees C for 1 min treatments. The activity of phenylalanine ammonia lyase (PAL) resposible for in the synthesis of phenolic substances was the least in 42 degrees C for 2 min treatment. Whereas, PAL activity of the chicons treated at 42 degrees C for 2 min and at 45 degrees C for 1 min were significantly lower than that of control. However, red discoloration was progressed as similar level with that of control in the basal part of chicon at 45 degrees C for 2 mm. The contents of total phenolic compounds and PAL activity in this treatment were not significantly different from those in control. The polyphenol oxidase (PPO) activity which causes red discoloration of cut tissues was low in all the treatments including 42 degrees C and 45 degrees C treatment at which no inhibition effects of the red discoloration of basal part of chicon were observed. When the correlation coefficient between each investigated index was tested, most of them showed high correlation except the PPO activity and particularly and the red discoloration index and sensory evaluation Delta h values, and PAL activity and total phenolic compounds content were r = 0.927**, and r = 0.942**, respectively.

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