Delayed  yellowing  of  broccoli  florets  by  ethanol:Some  physio-biochemical  changesduring  storage

Dewoowoogen  P. Baclayon,; Toshiyuki  Matsui,

Delayed yellowing of broccoli florets by ethanol:Some physio-biochemical changesduring storage

Dewoowoogen P. Baclayon | Toshiyuki Matsui

Abstract:

Harvested broccoli heads rapidly senesces after it is severed from the mother plant due to complex metabolic processes occurring in tissues. Specifically, abrupt increase in ethylene and decline in sucrose were reported. To elucidate further these changes, 25% ethanol was applied in heads prior to storage. The relationship between postharvest yellowing of florets and ethylene production, 1-aminocyclopropane-1- carboxylate oxidase (ACO) activity, sugar contents and respiration rate are determined. Results revealed that the onsets of climacteric rise in ACO activity and ethylene production were a day delayed by ethanol application. These results may suggest that ethanol inhibits ethylene synthesis by slowing down the activity of ACO at earlier storage period only. It is likely that due to volatilization of ethanol, the dilute concentration could be much less effective at overcoming its inhibitory effect on ethylene synthesis during the later stage of storage. Furthermore, the almost constant levels of sucrose from days 1 to 3 in the treated florets could be attributed to less consumption of respiratory substrate as exhibited by lower CO2 production. It is, therefore, likely that the relatively higher level of sucrose in treated florets has influenced the responsiveness of the floral tissue to ethylene. Overall, ethanol application appears to delay the metabolic processes which lead to the climacteric rise in ethylene, thereby delaying the onset of floret yellowing in broccoli. Prior to the appearance of visual sign of quality deterioration, significant changes in ACO activity and sucrose level have occurred. Thus, it is considered that yellowing is a late event in broccoli postharvest senescence preceded by significant physio-biochemical changes.

References:

ABELES, F.B., P.W. MORGAN and M.E. SALVEIT, JR. 1992. Ethylene in Plant Biology (2^nd ed), Acad. Press, Inc., San Diego, CA, USA.
AHARONI, N., S. PHILOSOPH-HADAS and R. BARKAI-GOLAN. 1985. Modified atmospheres to delay senescence and decay of broccoli. Proc. 4^th Natl. Controlled Atmosphere Conf., Dept. of Hort. Sci., Raleigh, N.C. Hort. Rpt. 126: 169-177.
FERNANDEZ-MACULET, J.C. and S.F. YANG. 1992. Extraction and partial characterization of the ethylene-forming enzyme from apple fruit. Plant Physiol. 99:751-754.
HEINS, R.D. 1980. Inhibition of ethylene synthesis and senescence in carnation by ethanol. J. Amer. Soc. Hort. Sci. 105: 141-144.
HYODO, H., S. MOROZUMI, C. KATO, K. TANAKA and H. TERAI. 1995. Ethylene production and ACC oxidase activity in broccoli flower buds and the effect of endogenous ethylene on their senescence. Acta Hort. 394: 191-198.
IRVING, D.E. and P.L. HURST. 1993. Respiration, soluble carbohydrates and enzymes of carbohydrate metabolism in tips of harvested asparagus spears. Plant Sci. 94: 89-97.
LANCASTER, J.E., C.E. LISTER, P.F. REAY and C.M. TRIGGS. 1997. Influence of pigment composition on skin color in a wide range of fruit and vegetables. J. Amer. Soc. Hort. Sci. 122: 594-598.
LIU, X.J., R. NAKANO, Y. KUBO and A. INABA. 2000. Extraction and properties of 1-aminocyclopropane-1-carboxylate synthase in banana fruit. J. Jpn. Soc. Hort. Sci. 69:696-701.
LURIE, S. 2006. The effect of high temperature treatment on quality of fruits and vegetables. Proc. IVth IC on MQUIC. Acta Hort. 712: 165-173.
MCGUIRE, R.G. 1992. Reporting of objective color measurements. HortScience 27: 1254-1255.
MLIKOTA, GF., J.L. SMILANICK, J.M. GHOSOPH and D.A. MARGOSAN. 2005. Impact of postharvest hot water or ethanol treatment of table grapes on gray mold incidence, quality and ethanol content. Plant Disease 89: 309-316.
NISHIKAWA, F., T. IWAMA, M. KATO, H. HYODO, Y. IKOMA and M. YANO. 2005.Effect of sugars on ethylene synthesis and responsiveness in harvested broccoli florets. Postharvest. Biol. Technol. 36: 157-165.
PRAMANIK, B.K., T. MATSUI, H. SUZUKI and Y. KOSUGI. 2004a. Changes in acid invertase activity and sugar distribution during postharvest senescence in broccoli. Pakistan J. Biol. Sci. 7: 679-684.
SALVEIT, M.E., JR. and A.R. SHARAF. 1992. Ethanol inhibits ripening of tomato fruit harvested at various degrees of ripeness without affecting subsequent quality. J. Amer. Soc. Hort. Sci. 117: 793-798.
SALVEIT, M.E., JR. and F. MENCARELLI. 1988. Inhibition of ethylene synthesis and action in ripening tomato fruit by ethanol vapors. J. Amer. Soc. Hort. Sci. 113: 572-576.
SITTHIWONG, K., T. MATSUI, N. OKUDA and Y. KOSUGI. 2007. Cloning and sequencing of sucrose synthase cDNA from vegetable soybean and its expression during storage at 20°C. Biotechnology 6: 184-192.
SUTHUMCHAI, W., T. MATSUI, K. KAWADA and Y. KOSUGI. 2007. Sugar metabolizing enzymes activities in lettuce head during low temperature storage. Asian J. Plant Sci. 6:568-576.
TIAN, M.S., C.G. DOWNS, R.E. LILL and G.A. KING. 1994. A role for ethylene in the yellowing of broccoli. J. Amer. Soc. Hort. Sci. 119: 276-281.
TIAN, M.S., T. ISLAM, D.G. STEVENSON and D.E. IRVING. 1997. Color, ethylene production, respiration and compositional changes in broccoli dipped in hot water. J. Amer. Soc. Hort. Sci. 122: 112-116.
WANG, C.Y. 1977. Effect of aminoethoxy analog of rhizobitoxine and sodium benzoate on senescence of broccoli. HortScience 12:54-56.