STUDIES ON CULTIVATION AND KEEPING QUALIT Y OF BEAN SPROUTS .16. CHANGES IN NUTRIENTS OF THICK BEAN SPROUTS AFTER PHYTOHORMONE-TREATED CULTURES

We cultured thick bean sprouts by immersion in a 10 ppm phytohormone s olution of auxin (IAA), cytokinin (CBA), abscisic acid (ABA), or gibbe rellin (GA(3)), and evaluated changes in the content of each nutrient at the time of harvesting in comparison with conventional culture meth ods as a control. After cultivation by the phytohormone treatment, bot h soybean and mung bean thick sprouts showed a similar state of growth . In both types of thick bean sprouts, changes in the contents of nutr ients were affected by the growth state after sprouting. Compared with the control method, the contents of nutrients increased after the cul ture with IAA or CBA with growth inhibitory effects but decreased afte r the culture with ABA or GA(3), with growth promoting effects. The co ntents of major nutrients (protein, lipids, sugars, fibers, and ash) g radually decreased in the early period of culture (1-3 days) but marke dly decreased in the middle period (4-5 days) appropriate for harvesti ng and the terminal period (6-7 days) showing root growth and cotyledo n formation. The contents of moisture and vitamin C (L-AsA) showed rec iprocal changes to those of the major nutrients, increasing with cultu re period. Niacin and vitamins B-1 and B-2 as water-soluble vitamins d ecreased from the early to middle period of culture but were slightly increased in the terminal period, reaching a peak. The major nutrients and L-AsA increased after the culture with IAA or CBA but decreased a fter the culture with ABA or GA(3) suggesting disadvantages of the lat ter phytohormone cultures. The contents of niacin and vitamin B-1 and B-2 did not markedly differ between the phytohormone-treated and contr ol cultures. Phytohormone treatment of cultures produced differences i n the contents of nutrients in thick bean sprouts according to the deg ree of involvement of each phytohormone in growth after sprouting. Aft er the culture with IAA or CBA which inhibit growth, nutrient degradat ion and synthesis became slow, and growth-associated nutrient consumpt ion decreased. On the other hand, after culture with ABA or GA(3) whic h promote growth, the reverse phenomenon occurred; i.e. the contents o f nutrients decreased compared with controls.