乙烯及貯藏條件對採收復蘆筍嫩莖長度、重量及老化之影響

Effects of Ethylene and Storage Conditions on the Length, Weight and Toughening of Post Harvest Asparagus Spears

本文主旨在探討目前臺灣多數蘆筍加工廠對採收後蘆筍之處理方式是否妥善。實驗內容包括研究在不同乙烯濃度環境中，貯藏溫度、筍基浸水與否及貯藏日數對白、綠二種蘆筍嫩莖長度、重量及老化之影響。本文試圖解答二個問題：一、採收後之蘆筍是否應當浸水？二、乙烯是否為促進採收後蘆筍老化的最主要因子？結果顯示單獨因子中，僅浸水會顯著影響綠蘆筍嫩莖長度及重量的增加。當各因子相互作用時，則浸水和溫度配合亦有顯著影響， 而乙烯濃度及貯存日數屬於次要。就乙烯而言，蘆筍嫩莖之累積乙烯釋放量與溫度成正比，且一般以綠蘆筍在相等重量時可放出較大量乙烯。生統分析結果顯示，白蘆筍中，除乙烯以外，其他單獨各因子，如貯存日數＞溫度＞浸水依次顯著影響用以表示老化程度之截切值。故知貯存環境中的乙烯顯然不是影響蘆筍嫩莖老化的主要因子。在對照組及高乙烯濃度處理組，貯存二天之內反而以浸水組較不浸水組質地粗硬，故知短時間貯存，如一或二天之內，自蘆筍以不浸水為宜，但一定要用低溫，且越快加工品質越佳。綠蘆筍質地之老化則僅受浸水與否顯著影響。因室溫貯存雖不影響老化，但易使筍基受微生物侵擾而腐爛，故建議採收後之綠蘆筍應在低溫下（5°C）貯存，並且筍基浸水，才可保筍莖之幼嫩。

The main purpose of this paper was to study whether the post-harvest treatment method applied by most of the food processing companies in Taiwan for asparagus was proper? Storage conditions refered to storage temperature, soaking of spear base in water and days of storage. Effects of ethylene and storage conditions on the length, weight and toughening of post harvest asparagus spears were studied. This paper attempted to answer two questions: 1. Is it necessary to soak spear base in water? 2. Is ethylene the most important factor in the toughening of post-harvest asparagus spears? The results indicated that among single factors, only soaking treatment showed significant effect on the increase of length and weight of the spears. But in the combination of factors, soaking and temperature also showed significant effect. While ethylene concentration and days of storage were less important. For ethylene, the results indicated that the amount of accumulated ethylene evolution increased with temperature. But generally green asparagus evolved more ethylene than the same weight of white asparagus. Statistical analysis pointed out that in white asparagus, factors other than ethylene such as days of storage, temperature, and soaking, in this order, all significantly affected shear press value which was the indicator of the degree of toughening. Thus it was concluded that ethylene was evidently not the main factor in the toughening process. In both control and high ethylene concentration treatments of white asparagus, soaking samples were tougher than the non-soaked within two days of storage. Therefore, it was recommended for better quality of white asparagus, it should be processed as soon as harvested. If it has to be stored for one day or two, low temperature without soaking was required for reducing the toughening process. For green asparagus, only soaking treatment was significantly related to the toughening. Although temperature was not the main factor in toughening, room temperature storage usually led to the decay of the spear base by the attack of microorganism. Thus low temperature and soaking were recommended for the storage of green asparagus spears.