Department of Horticulture, Kangwon National University1
Agricultural and Life Science Research Institute, Kangwon National University2
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°C and for 2 min and 4 min at 42°C, and for 1 min and 2 min at 45°C, along with control (for one min at 20°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°C was lower at 42°C for 2 min, 42°C for 4 min and 45°C for 1 min treatments. The color change value of the basal part in chicon measured by colorimeter showed that the lowest △a* and △h were maintained in the basal part of chicon treated at 42°C for 2 min. Whereas, color changes in 42°C for 2 min and 45°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°C for 2 min, 42°C for 4 min and 45°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°C for 2 min treatment. Whereas, PAL activity of the chicons treated at 42°C for 2 min and at 45°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°C for 2 min. 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°C and 45°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 △h values, and PAL activity and total phenolic compounds content were r = 0.927**, and r = 0.942**, respectively.
1. Bae, J.H., K.W. Park, and H.M. Kang. 2005. Effects of packing materials, light condition and storage temperature on MAP storage of chicon. J. Bio-Environment Cont. 14:67-75.
2. Berset, C. and P. Caniaux. 1983. Relationship between color evaluation and chlorophyllian pigment content in dried parsley leaves. J. Food Sci. 48:1854-1857.
3. Charles, F., C. Guillaume, and N. Gontard. 2008. Effect of passive and active modified atmosphere packaging on quality changes of fresh endives. Postharvest Biol. Technol. 48:22-29.
4. Castañer, M., I.G. María, M.V. Ruíz, and F. Artés. 1999. Browning susceptibility of minimally processed baby and romaine lettuces. Eur. Food Res. Technol. 209:52-56.
5. Hong, S.I., S.M. Son, H.H. Lee, and D.M Kim. 2004. Effect of hot water treatment on storage quality of minimally processed onion. Kor. Food Sci. Technol. 36:239-245.
6. In, B.C. and J.G. Kim. 2008. Effect of precooling and harvesting at different times on respiration, browning and microbial growth of fresh-cut iceberg lettuce. Kor. J. Hort. Sci. Technol. 26:258-264.
7. Jung, H.J., H.T. Seo, I.L Choi, T.J. Yoo, J.S. Son, J.H. Won, I.S. Kim, and H.M. Kang. 2010. Effect of Precooling Treatments on the Storability of Chicon during MA storage. J. Bio- Environment Cont. 19(4):360-365.
8. Kavrayan, D. and T. Aydemir. 2001. Partial purification and characterization of polyphenol oxidase from peppermint (Mentha piperita). Food Chem. 74:147-154.
9. Kang, H.M. and M.E. Saltveit. 2003. Wound-induced PAL activity is suppressed by heat-shock treatments that induce the synthesis of heat-shock proteins. Physiologia Plantarum 119:450-455.
10. Ke, D. and M.E. Saltveit. 1989. Wound-induced ethylene production, phenolic metabolism and susceptibility to russet spotting in iceberg lettuce. Physiol. Plant. 76:412-418.
11. Loaiza-Velarde, J.G., F.A. Toma´s-Barbera´n, and M.E. Saltveit. 1997. Effect of intensity and duration of heat-shock treatments on wound-induced phenolic metabolism in iceberg lettuce. J. Am. Soc. Hortic. Sci. 122:873-877.
12. Luh, B.S. and B. Phithakpol. 1972. Characteristics of poly-phenoloxidase related to browning in cling peaches. J. Food Sci. 37:264-268.
13. Park, K.W. 1994. Western vegetable. Korea Univ. Publishing, Seoul, Korea. p. 271-281.
14. Peiser, G., G. Lo´pez-Ga´lvez, M. Cantwell, and M.E. Saltveit. 1998. Phenylalanine ammonia lyase inhibitors control browning of cut lettuce. Postharvest Biol. Technol. 14:171-177.
15. Rivero, R.M., J.M. Ruiz, P.C. García, L.R. López-Lefebre, E. Sánchez, and L. Romero. 2001. Resistance to cold and heat stress: Accumulation of phenolic compounds in tomato and watermelon plants. Plant Sci. 160:315-321.
16. Rodríguez-López, J.N., L.G. Fenoll, M.J. Penalver, P.A. García- Ruiz, R. Varón, F. Martínez-Ortíz, and F. García-Cánovas. 2001. Tyrosinase action on monophenols; Evidence for direct enzymatic release of o-diphenol. Biochemica Biophysica Acta. 1548:238-256.
17. Saltveit, M.E. 2000. Wound induced changes in phenolic metabolism and tissue browning are altered by heat shock. Postharvest Biol. Technol. 21:61-69.
18. Saltveit, M.E. and L. Qin. 2008. Heating the ends of leaves cut during coring of whole heads of lettuce reduces subsequent phenolic accumulation and tissue browning. Postharvest Biol. Technol. 47:255-259.
19. Salman, A., P. Goupil, H. Filgueiras, F. Charles, G. Ledoigt, and H. Sallanon. 2008. Controlled atmosphere and heat shock aVect PAL1 and HSP90 mRNA accumulation in fresh-cut endive (Cichorium intybus L.). Eur. Food Res. Technol. 227: 721-726.
20. Takahashi, T., K. Abe, and K. Chachin. 1996. Studies on the physiological and chemical changes in shredded cabbage, 3: Effect of air-exposure at low temperature on physiological activities and browning of shredded cabbage. J. Japan. Soc. Food Sci. Technol. 43:663-667.
21. Van Gelder, C.W.G., W.H. Flurkey, and H. Wichers. 1997. Sequence and structural features of plant and fungal tyrosinases. Phytochem. 45:1309-1323.
22. Vanstreels, E., J. Lammertyn, B.E. Verlinden, N. Gillis, A. Schenk, and B.M. Nicolaı. 2002. Red discoloration of chicory under controlled atmosphere conditions. Postharvest Biol. Technol. 26:313-322.