椪柑冷藏之研究

Cold Storage Studies of Ponkan Oranges (Citrus reticulata, Blanco)

椪柑為臺灣重要外銷柑桔之一，自日本開放進口以後，地位更顯重要。惟因不耐貯運，外銷腐損率甚高，致使外商卻步，不敢大量進口。椪柑在國內及海外華僑社會春節期間消費甚多，然須於冬至前採收，以避免霜害。本實驗旨在研究冷藏對控制椪柑腐敗及延長市場供應之效果。供試果實於採收前於一星期全株噴布TBZ或Benlate藥劑1000ppm。採收後逐果套以無孔塑膠袋，置於相對濕度為85-90%，溫度為0, 5, 10, 15及20℃之冷藏庫中12星期。每隔2-4星期檢查果實之腐爛率、失重率、傷風和著色率。茲將結果摘要如下：（1）果實腐爛率與貯藏溫度成正比。果實貯藏期為一個月時，20℃即有良好的防腐效果；貯藏二個月者溫度不可高於15℃；但貯藏三個月之久者，以10℃為最好。Benlate及TBZ藥劑在採收前施用對控制採收後腐敗有良好的效果，尤以Benlate效果顯著，但其藥效不及TBZ持續。（2）果實套袋與否，對失重率影響甚大，未套袋果失重約8-10倍於套袋果。置於溫度10℃以上之果實，失重更為顯著。（3）果實於5及0℃貯藏達六星期時，即有傷風現象發生，而套袋果實較無套袋者嚴重，果實經三個月貯藏後，幾全罹水腐病（Watery Breakdown）之傷風。溫度在10℃以上則無傷風之現象。（4）果實著色率與溫度成正比，貯藏10℃以上之果實皆能正常著色。果實置於5℃及0℃者著色緩慢，並於六星期貯藏後，著色機能因遭傷風破壞而無法呈現橙色。概言之，柑桔於採收前噴佈TBZ及Benlate等藥劑，對貯藏效果有良好影響，因其操作簡便，似值得推薦使用。柑桔行短期貯藏時，如不超過一個月，可貯藏在20℃，如貯藏期長達二個月，溫度須低於15℃；如長達三個月則以10℃為佳，但不可低於10℃。

The effects of various temperatures, poly-wrappere and two fungicides on the storgae life of Ponkan oranges were studied. Test fruits were sprayed with 1000 ppm of Henlate or TBZ one week before harvest by hand-clipping and were then individually placed in non-perforated unsealed polyethylene bags in the storage maintained at 85-90% R. H. and 32, 41, 50, 59 and 68° F. The rates of decay, chilling injury, weight toss and coloring were investigated at intervals of 1, 2, and 3 months. The rate of total decay was low in the lots stored below 68° F, during the first month of storage and, at the end of three months in storage, was low only in the tots stored below 50° F. Chilling injury as visualized by pitting, scald, and watery breakdown began to show up after 6 weeks in storage at both 32 and 41° F. Fruits wrapped with polyethylene film had less pitting but more watery breakdown than the unwrapped. The rate of weight loss and degreening was in proportional to the storage temperature. The fruit wrapped with polyethylene film had a superior control on water loss than the un-wrapped fruit. The rate of degreening was very slow at 32 and 41° F., and woo rapid at temperatures above 50° F. Thus, we would recommand to treat Pankan oranges with either Benlate or TBZ one week before picking and then hold the fruit at a temperature not higher than 68° F. for short term storage up. to one month; 59° F. up to two months; and not lower than 68° F. for long term storage up to three months.