Abstract: A vacuum processing apparatus includes a decompressable process container; a supply port configured to supply, to the process container, an ionic liquid that absorbs an oxidizing gas; and a discharge port configured to discharge the ionic liquid supplied to the process container. A recess is provided at a joint portion between members constituting the process container. The supply port is configured to supply the ionic liquid to the recess, and the discharge port is configured to discharge the ionic liquid supplied to the recess.

Abstract: A quality improver for producing bread, comprising at least one component (i) selected from malt, rice fermentation product, and wheat fermentation product and (ii) biotin. Preferably it further contains mevalonolactone and/or mevalonic acid or a lactic acid fermentation product of soy bean. A seed dough is obtained by kneading cereal powder, yeast, and the quality improver for producing bread and subjecting the mixture to primary fermentation. The bread has a sufficient volume, a good shape, a soft feeling upon eating, a good flavor (fragrance and taste), excellent storage stability and contains vitamins, proteins and minerals abundantly. The seed dough containing the quality improver can be circulated.