Abstract
The effects of using soup-extraction bags on the flavor and extractable components of soup stock from niboshi powder and of different materials for the bags on the extraction process were evaluated. Sensory tests showed that the aroma of the soup stock was improved and the fishy smell was weakened, and that the bitterness and astringency were reduced with no change in the umami taste when using polyester and cupra extraction bags to make soup stock from niboshi powder. There was no clear difference in the results of sensory tests according to the material used for the bag. Soup stock prepared by using an extraction bag resulted in the acidity, amino nitrogen contents and total extractable components of the soup stock reaching equilibrium after 2 min of boiling, the level tending to be less than that in the soup stock prepared without using an extraction bag. The 5'-IMP, 5'-AMP, and free amino acid concentrations also nearly reached equilibrium after 2 min of boiling when using an extraction bag. Compared with the soup stock prepared without using an extraction bag, the amount of these components had reached nearly the same level after 2 min of boiling when a polyester bag was used, but did not reach the level when a cupra bag was used, probably because the hydrophilic cupra fibers absorbed these components. The better aroma and weaker fishy smell of the soup stock prepared by using an extraction bag are considered to have been due to the absorption of lipid and the characteristic smell derived from the oxidation and decomposition of lipid by the extraction bag.
