Abstract
Niraki is the general term for salted preserves described in some ancient records including the “Engi-Shiki”, the Laws and Regulations issued in A. D.908. Together with salt, smashed bark of elm was added as an indispensable ingredient for preparing niraki. Presently, the purpose of its addition is not known.
Niraki of daikon, Japanese radish, was prepared according to the recipe described in the ancient references by using the smashed barks of aki-nire,, or autumn elm (Ulmus Parvifolia) and haru-nire, or spring elm (Ulmus davidiana var. Japonica) and subjected to chemical analysis and bacterial tests. It was found that the concentration of glutamic acid in the acid hydrolyzate of the aki-nire-niraki, haru-nire-niraki and the control (salted preserves without the powdered barks) were about 3,8 and 5 times greater than those without the acid hydrolysis, respectively. A greater amount of glutamic acid, the well-known umami substance, was found in aki-nire niraki than in haru-nire niraki.
The water-soluble acetone extract of aki-nire inhibited the growth of B. subtilis and E. coli. It is suggested that the elm bark powder plays an antiseptic role in the salted preserves.
