jf5b03080_si_001.pdf (261.93 kB)
Soybean Ferritin Forms an Iron-Containing Oligomer in Tofu Even after Heat Treatment
journal contribution
posted on 2015-10-14, 00:00 authored by Taro MasudaFerritin,
a multimeric iron storage protein distributed in almost
all living kingdoms, has been highlighted recently as a nutritional
iron source in plant-derived foodstuffs, because ferritin iron is
suggested to have high bioavailability. In soybean seeds, ferritin
contributes largely to the net iron contents. Here, the oligomeric
states and iron contents of soybean ferritin during food processing
(especially tofu gel formation) were analyzed. Ferritin was purified
from tofu gel as an iron-containing oligomer (approximately 1000 Fe
atoms per oligomer), which was composed of two types of subunits similar
to the native soybean seed ferritin. Circular dichroism spectra also
showed no differences in α-helical structure between native
soybean ferritin and tofu ferritin. The present data demonstrate that
ferritin was stable during the heat treatment (boiling procedure)
in food processing, although partial denaturation was observed at
temperatures higher than 80 °C.