The Keeping Quality of Chinese Chive (Allium tuberosum Rottler) by Low Temperature and Seal-packaging with Polyethylene Bag

Abstract

Chinese chive is in demand as a seasoning vegetable all the year round. But, the deteriorations such as yellowing, rotting and wilting are very rapid at high temperatures. Thus, the shelf life is only one or two days in summer season, which is becoming a serious problem. Prevention of the deterioration by precooling combined with the seal-packaging with polyethylene bag was studied in this experiment. Precooling combined with the seal-packaging was very effective in preventing yellowing, rotting and wilting as well as in reducing respiration and losses of some components such as chlorophyll, reduced ascorbic acid and carotene. The seal-packaging alone was fairly effective in preventing the deterioration, but at high temperatures, it caused the metabolic abnormality resulting in visible injuries and abnormal odors. In such cases, making a few pin-holes in polyetylene bag prevented the abnormality, and prolonged the shelf life in some extent.
Based on these results, a recommendable shipping system was established and applied practically. It may be summarized as follows.
1. Chinese chives are prepared and bundled with a rubber band by about 110g.
2. Ten bundles are seal-packaged in a polyethylene bag (size: about 30×45cm, film thickness: about 0.025mm, with or without a few pin-holes).
3. Four seal-packaged bags are vertically packed in a corrugated box (size: about 26×30×36cm, with side vents), and precooled to about 5°C by room cooling method within a day.
4. The precooled produce is shipped generally by trucks with insulated box or sheets.
In this system, strict adherence to optimums in precooling and transit can be relaxed a little because of modified atomosphere effects by the seal-packaging.