บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Interaction of oxygen, carbon dioxide, ethylene and 1-MCP in controlling physiological deterioration of fresh-cut lettuce.

Rodov V., Vinokur Y., Horev B., Goldman G., Aharoni N.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 25

2004

บทคัดย่อ

Interaction of oxygen, carbon dioxide, ethylene and 1-MCP in controlling physiological deterioration of fresh-cut lettuce.   Shredded lettuce is prone to enzymatic oxidative browning (EOB), which reduces its marketing appeal and nutritional value.White tissues of the leaf base around the midrib are especially susceptible to the EOB.Modified atmosphere (MA) packaging with 0.5 to 3 kPa of oxygen is commonly used to reduce the severity of EOB.However, these conditions may lead to oxygen depletion in the package and off-flavour development.An alternative way to control EOB in fresh-cut lettuce was sought in this work.

Keeping ‘Iceberg’ lettuce in sealed packages containing super atmospheric oxygen concentration (above 75 kPa) was found to effectively reduce the EOB in lettuce tissues without the risk of oxygen depletion.At the same time, these conditions increase the incidence of dark discoloration in small primordial leaves of lettuce, most probably due to the damaging effect of elevated carbon dioxide accumulation which reached 10 to 25 kPa, depending o­n storage temperature.Absorption of carbon dioxide from the high-oxygen atmosphere by calcium hydroxide surprisingly resulted in the appearance of severe russet spotting, anotherphysiological disorder of lettuce firmly associated with ethylene effect.It might be suggested that synthesis and/or effect of ethylene were enhanced in the absence of carbon dioxide, which is well known as ethylene antagonist.Application of 1-MCP durably blocks the effect of ethylene, alleviates russet spotting in lettuce and therefore can reduce the negative effect of CO2 absorption in high-oxygen MA.

The combined effect of 1-MCP treatment, high oxygen atmosphere and carbon dioxide absorption improved the appearance of shredded ‘Iceberg’ lettuce.Possible physiological mechanisms of the interaction will be discussed.