Improvement of Bean Sprouts Production by the Intermittent Treatment of Ethylene Gas

Studies on Cultivation and Keeping Quality of Bean Sprouts Part VII

Abstract

Aiming at efficient production of bean sprouts having heavier (thick) hypocotyls, intemittent ethylene treatment was investigated. Soybeans, mung beans, and adzuki beans were soaked in 30°C-water for 5 hours and planted on sprouting beds in the dark at 30°C. Water was sprayed for 15 minutes at intervals of 4 hours, and air containing 10, 50, or 100ppm of ethylene was flushed for 60 minutes once every day starting 12 hours after planting. The ethylene treatment showed striking effects on the growth and the quality of bean sprouts. The treatment with 100ppm ethylene resulted in unfavorable effects such as retardation of hypocotyl elongation, hardening and yellowing of hypocotyl, and growth promotion of lateral roots, while it increased weight and vitamin C content most strikingly. With 50ppm of ethylene, elongation and thickening of hypocotyl were properly enhanced, and marked increases of weight and vitamin C content were found as compared with nontreated materials. Yellowing and hardening of hypocotyls and growth promotion of lateral roots occurred by the treatment, but they were not serious problems when harvested at a suitable time. The treatment with 10ppm ethylene showed a similar but inferior effects to that of 50ppm. With the treatment of 50ppm ethylene, cultiVation period was shortened by 2-3 days. Thus the intermittent treatment with 50ppm ethylene seems to be useful for producing efficiently the heavier hypocotyl bean sprouts which are rich in vitamin C.