The vinegar fermentation by batch culture used in the
present study was rather inefficient in terms of productiv-
ity due to its long duration (7). To overcome this draw-
back, the development of a continuous onion vinegar
fermentation system is ongoing.
In conclusion, it was found that vinegar could be suc-
cessfully produced from the juice extracted from onions
using yeast and Acetobacter. Although the sugar con-
tent in onions was slightly low for the production of nor-
mal vinegar, it could easily be supplemented by adding
sugar to the onion juice. The nutrition analyses revealed
that onion vinegar has high contents of organic acids,
amino acids, and minerals. This new type of vinegar is
expected to become a worthy condiment produced from
worthless onions.