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ID 11128
Eprint ID
11128
FullText URL
Title Alternative
Physiological Aspect of Postharvest Handling Conditions in Horticultural Crops
Author
Nakamura, Reinosuke
Abstract
The physiological responses of fruits and vegetables toransit conditions such as vibration, temperature, humidity and air composition were investigated as a basic problem of postharvest handling of horticultural crops. Temperature: The respiratorry metabolism of some fruits and vegetables was disturbed by rapid change of ambient temperature exceeding the range of 20℃. Quality deterioration of some vegetables under fluctuating temperatures was rapid compared to those held under constant temperature. These effects of temperature on the physiology and keeping quality of horticultural crops were different depending on the kind of commodity and its developmental stage. Air composition: Critical O2 concentration estimated by extinction point, the lowest O2 level at which the respiratory quotient remains at 1.0, was different for the various horticultural crops. The respiratory responses of fruits and vegetables to high CO2 were different and depended on the kind of commodity and its developmental stage. In non-climacterric fruits and several vegetables, in which ethlene evolution was not detected, high CO2 had litter or no effect at all on respiration. In some vegetables such as cucumber and lettuce treated with high CO2, ethylene evolution was induced during or after treatment and them respiration increased. These results indicate that the respiratory response of fruits and vegetables to high CO2 might be mediated through the effects of CO2 on ethlene synthesis and/ or action. Humidity: The respiratory responses of horticultural crops to relative humidity seemed to be classified into three groups; accelerative, inhibitive and insensitive at low humidity. In climacteric fruit such as bananas, ripening was accelerated under low humidity. Softening was observed in some fruits and vegetables nuder low humidity. The induction of softening seemed to be independent of endogenous ethylene concentration. These results may indicate that polygalacturonase activity is induced and then degradation of cell wall polysaccharides is initiated by water deficit stress under low humidity. Vibration: Some fruits and vegetables were physiologically sensitive to artificial vibrating conditions which were not sufficient to produce direct injury. Through intensive vibration, some metabolic pathways were suppressed while others were activated. AS a result, intensive vibration above the critical point for every fruit and vegetable caused quality deterioration. Based on the above observations, improvement of postharvest handling techniques of horticultural crops are discussed from a physiological point of view.
Abstract Alternative
園芸生産物の流通工程が時間的・距離的に長くなるに従って、この間での管理が品質保持の上で重要な課題になってくる。本研究は、主として輸送工程に焦点を絞りながら、技術改善の基礎資料を得ることを目標として実施されたものである。まず、現実の輸送環境の実態調査を行い、問題点の指摘を行った上で、それらに基づいてシミュレーション研究を実施し、振動、温度、湿度及び空気組成環境ごとに生産物の生理的反応を再整理して、技術改善の方向性について生理学的見地から論じようとした。温度:較差20℃にも及ぶような急激な温度変動は生理的にみて好ましくないこと、小さな周期的変動も定温に比べて鮮度低下が大きいことを明らかにした上、いずれも種類によって耐性が異なることを示唆した。空気組成:呼吸商1を維持する最小酸素濃度である消滅点からみた酸素濃度の限界点は種類によって異なった。高炭酸ガスと呼吸活性との関係をみると、種類によって抑制されるもの、変化がないもの、逆に促進されるものがあり、抑制されるものはエチレン生成の抑制を伴っていることが明らかとなった。このことから、高炭酸ガスの鮮度保持効果は、直接的に呼吸活性を抑制するのではなく、エチレン生成の抑制を介してあらわれるものと思われた。温度:低湿に伴う萎れによって、種類によって呼吸活性が抑制される場合、変化がない場合、促進される場合があった。クライマリテリック型果実では低湿で成熟促進がみられた。急激な萎れによってエチレン生成が誘導された。さらに、萎れによって肉質軟化が促進され、これはエチレン生成とは無関係に萎れストレスによって直接PG活性が誘導されることが一因であることを示唆した。振動:振動によって呼吸活性の増大がみられた。振動刺激が一定強度以上になると生理的に変調が誘発され、ひいては食味低下に連なることを示した。以上の成果に基づいて、主として生理的側面から輸送工程を含めて流通技術改善の方向について論じた。
Keywords
horticultural crops
postharvest handling
postharvest physiology
respiration
ethlene biosynthesis
Published Date
1998-02
Publication Title
岡山大学農学部学術報告
Publication Title Alternative
Scientific reports of the Faculty of Agriculture, Okayama University
Volume
volume87
Issue
issue1
Publisher
岡山大学農学部
Publisher Alternative
Faculty of Agriculture,Okayama University
Start Page
251
End Page
264
ISSN
0474-0254
NCID
AN00033029
Content Type
Departmental Bulletin Paper
language
日本語
File Version
publisher
Refereed
False
Eprints Journal Name
srfa