香蕉密封包裝用乙烯吸收劑之研究

Studies on the Ethylene Absorbents in Sealed Polyethylene Box-liners of Bananas

把一磅純溴素澆於四磅活性碳上混和之，可以制成溴化活性碳，約含溴素20%。把粒狀的活性氧化鋁或蛭石浸在含2.8%過錳酸鉀1%碳酸鈉的溶液中過夜，而後淋乾，再在105℃烘乾（切忌易於氧化之容器），即成過錳酸鉀活性氧化鋁或過錳酸鉀蛭石，前者含過錳酸鉀1.25%，後者含5.39%。以上三種製劑均能自空氣中吸收乙烯，使其濃度降低至不致影響香蕉後熟的程度，故可與香蕉同裝於塑膠袋內作為乙烯吸收劑，約可使香蕉的貯運壽命平均增加一倍。三種乙烯吸收劑中，以過錳酸鉀蛭石比較輕便而經濟，且不致大量奪取香蕉水份；如以白色蛭石為賦形劑，尚可自示過錳酸鉀之顏色變化及其對乙烯之吸收能力。

Three ethylene absorbents were prepared in the laboratory, tested for ability of removing ethylene from air, and packed with bananas of poor keeping quality in sealed polyethylene bags (0.03-0.05 mm) to study the effect of ethylene removal on the storage life of the fruit. All the experiments were carried out at 20℃. Brominated activated carbon was prepared by drenching and mixing four pounds of BPL granular carbon (Pittsburgg Activated Carbon) with one pound of pure bromine. The finished product contains 20% of bromine. For potassium permanganate, activated alumina and vermiculite were used as carriers. These two carriers were soaked overnight in a solution containing 2.8% of potassium permanganate and 1% of sodium carbonate, and then drained and dried at 105℃. The finished product ”KMnO4 on Activated Alumina” contains 1.25% KMnO4 and ”KMnO4 on Vermiculite” contains 5.39% KMnO4. After the air containing 1.0 ppm of ethylene is filtered through an absorber with any of the three ethylene absorbents, it no longer alters the ripening behavior as compared with the fruit stored in air without ethylene. 20 grams of brominated activated carbon, 50 grams of KMnO4 on activated alumina, and 10 grams of KMnO4 on vermiculite were packed with three kilograms of banana fingers in each of the sealed polyethylene bags. Oxygen and carbon dioxide in the sealed bags were occasionly analyzed. The time that elapsed before the carbon dioxide concentrations in the sealed bag abruptly rose was taken as the length of pre-climacteric phase of the fruit, and was based upon to compare the effect of treatment. On this basis, it is found that the average storage life of the bananas packed with any of the three ethylene absorbents was doubled as compared with the fruit packed without ethylene absorbent in the sealed polyethylene bags. When brominated activated carbon is used, it must be securely isolated from the fruit to avoid chemical injuries. Potassium permanganate is safe n this respect. It is recommended to use white carriers for potassium permanganate because of their self-indication effect. White vermiculite is about the best because of economy, light weight and low moisture absorbing.