Effect of exogenous zinc soaking on the growth and nutritional quality of mung bean sprouts

In order to develop a zinc- rich food,mung bean seeds were soaked for 8 h in zinc sulfate solutionsof different concentration of zinc( 0 ~ 200 mg Zn~(2+)/ L) and then cultivated for 96 h with deionized water. The influence of soaking with exogenous zinc on growth,zinc accumulation,phytic acid content and main nutrient components of mung bean sprouts was investigated.The results showed that zinc sulfate solutions in the concentration range of 25 ~ 75 mg Zn~(2+)/ L,especially 50 mg Zn~(2+)/ L,could improve hypocotyl length,root length,biology yield and main nutrient components of mung bean sprouts. Total free amino acid,vitamin C,soluble protein and soluble sugar reached 8.96 mg / g,23.76 mg /100 g,56.82 mg / g,and 6.62 mg / g in this concentration,respectively.Zinc content in mung bean sprouts increased by 90.9% ~ 617.0% within the experimental concentration range.Germination and exogenous zinc soaking resulted in the reduction of the phytic acid content by 61.5% and62.0%,respectively,and there was no significant difference between the two groups( p > 0.05). This study showed that proper concentration of exogenous zinc( < 75 mg Zn~(2+)/ L) can stimulate the germination of mung bean seeds and the growth of mung bean sprouts.In this way,the nutritional value of trace element zinc and the nutritional quality of mung bean sprouts were enhanced.