TaskLets provide a method for producing a fermented black onion which can drastically shorten the production period and can further improve the content of physiologically active ingredients since it is unnecessary for additives and can be rapidly produced in the state of onion as it is .SOLUTION:Transfer the polyphenol-quercetin component of the outer skin to raw onion by applying superheated steam including sterilization for over a specified period of time with superheated steam at a temperature of 170 to 450 ,Next, the onion was bagged and sealed,Production of fermented black onion characterized in that it is allowed to stand for 10 to 20 days at a temperature within the range of 55 to 80 C., fermented and ripened by self fermentation to increase the content of active ingredients in dry sample of onion Method.BACKGROUND OF THE INVENTION【課題】添加物が不要でタマネギそのままの状態で迅速に製造できるために製造期間を大幅に短縮することができ、かつ生理活性成分の含有量をより向上させることができる醗酵黒タマネギの製造方法を提供しようとする。【解決手段】生タマネギを、温度が170~450℃の過熱水蒸気で任意の定められた時間、殺菌を含めて過熱水蒸気をかけることにより外皮のポリフェノール・ケルセチン成分を生タマネギに移行させ、次いで当該タマネギを袋詰めして密封した上、温度が55~80℃の範囲内で10~20日間放置して自己醗酵で醗酵・熟成させ、タマネギの乾燥試料中の有効成分の含有量を増加させたことを特徴とする醗酵黒タマネギの製造方法。【選択図】 図1