【０００１】
【発明の属する技術分野】
本発明は、長期間乳化系の安定で、十分な粘度を有するジグリセリド含有酸性水中油型乳化物の製造法に関する。
【０００２】
【従来の技術】
近年、ジグリセリドが肥満防止作用、体重増加抑制作用等を有することが明らかにされるに至り（特許文献１参照）、これを各種食品に配合する試みがなされている。そして、ジグリセリドを高濃度に含むグリセリド混合物を油相に用いれば、脂肪量を低減した場合においても豊かな脂肪感を有し、風味が良好な食用水中油型乳化物が得られることが報告されている（特許文献２参照）。
【０００３】
しかしながら、ジグリセリドを高濃度で含有する油相を卵黄で乳化したマヨネーズ等の酸性水中油型乳化物は、保存中に亀裂が発生し、離水が滲出し、更に光沢がなく組織が荒れた外観となる等の問題が生じることが判明した。これを解決する技術として、例えば酸性水中油型乳化物中の全リン脂質に対しその１５％（リン量基準）以上をリゾリン脂質とすることにより、これらの問題が解決することが報告されている（特許文献３参照）。
【０００４】
【特許文献１】
特開平４−３００８２８号公報
【特許文献２】
特許第２８４８８４９号公報
【特許文献３】
特開２００１−１３８号公報
【０００５】
【発明が解決しようとする課題】
ところで、マヨネーズ類の酸性水中油型乳化物の長期保存安定性を向上させたり、商品として必要な粘度を得るためには増粘剤等の増量や新たな添加剤の添加も考えられ、ジグリセリドを高濃度で含有する油相を用いた場合にも、同様の効果を得ることはできる。しかし、風味や食感が損なわれる等の問題がある。
【０００６】
従って、本発明は、ジグリセリドを高濃度で含有する油相を用いた場合にも、増粘剤等の増量や新たな添加剤の添加なしに、長期間乳化系の安定で、十分な粘度を有する酸性水中油型乳化物の製造法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
そこで本発明者は、前記のジグリセリド含有酸性水中油型乳化物特有の問題を解決すべく種々検討したところ、通常は酸性物質の全量を水相中に添加した後に油相と混合するが、油相と混合する前の水相成分中の酸性物質の添加量を一定量以下に抑え、水相成分と油相とを混合した後に残りの食酢等の酸性物質を添加し、ｐＨを１以上低下させて乳化すると、安定性と粘度が顕著に向上することを見出した。また、酸性物質の多くを最後に添加することによる安定性と粘度の向上効果は、トリグリセリドを油相とする酸性水中油型乳化物ではほとんど得られず、ジグリセリドを含有する油相とする酸性水中油型乳化物特有の効果であることも見出した。
【０００８】
更に、工業化レベルの大量処理では、水相と油相を配合混合し予備乳化を行った後、精乳化工程を経て製造されている。しかし、精乳化工程で粘度を上げる負荷が高いと、せん断エネルギーが高くなりすぎ、Ｏ／Ｗ乳化物からＷ／Ｏ乳化物に転相してしまうことがあり、長期間の安定生産が困難となる。油相として通常の油脂（トリグリセリド）を用いた場合には、Ｏ／Ｗ乳化物を形成し易い性質があるため、転相現象は現れにくい。しかし、油脂にジグリセリドを含有する場合、油−水の界面張力が低くＷ／Ｏ乳化物を形成し易いことから、転相が起こり易い。そこで、この工程を採ると予備乳化物の粘度が上昇するため、精乳化工程で粘度を上げる負荷を低減でき、結果として転相を起こさずに安定生産でき、かつ長期間乳化系の安定で、粘度を向上させた酸性水中油型乳化物となることも見出した。
【０００９】
すなわち、本発明は、ジグリセリドを２０重量％以上含む油剤と水相を混合した後、酸性物質を添加し、ｐＨを１以上低下させる酸性水中油型乳化物の製造法を提供するものである。
【００１０】
【発明の実施の形態】
本発明方法においては、まずジグリセリドを２０重量％（以下、単に％で示す）以上含有する油相と水相とを混合する。このとき、油相と混合する前の水相中に添加する酸性物質を一定量以下に抑えることがポイントである。特に、酸性物質の中でも食酢（１０％酢酸含有）については、水相に添加する量は全系１００％に対して２％以下、好ましくは１％以下、更に好ましくは０％とし、残りは油相と混合した後に添加するのが好ましい。ここで油相は、ジグリセリドを２０％以上含有する油脂であり、低融点のものが好ましい。
【００１１】
当該ジグリセリドも、低融点であることが好ましく、具体的には、構成脂肪酸残基の炭素数が８〜２４、特に１６〜２２であることが好ましい。また不飽和脂肪酸残基の量は、全脂肪酸残基の５５％以上が好ましく、７０％以上がより好ましく、９０％以上が特に好ましい。ジグリセリドは、植物油、動物油等とグリセリンとのエステル交換反応、又は上記油脂由来の脂肪酸とグリセリンとのエステル化反応等任意の方法により得られる。反応方法は、アルカリ触媒等を用いた化学反応法、リパーゼ等の油脂加水分解酵素を用いた生化学反応法のいずれでもよい。本発明の酸性水中油型乳化物の油相中のジグリセリド含量は、脂質代謝改善食品（中性脂肪蓄積抑制）としての有効性の観点から２０％以上、更に３０％以上、特に３５％以上が好ましい。油相には、ジグリセリド以外に、トリグリセリド、モノグリセリド、遊離脂肪酸等を含有していてもよい。尚、乳化物の安定化等のため、油相中に高融点油脂、特に室温で固体である油脂を含有させてもよい。
【００１２】
また油相中には、更に血中コレステロール低下作用を有する植物ステロールを含有させてもよい。ジグリセリドと植物ステロールの併用により、血中コレステロール低下作用は、相乗的に高まり、脂質代謝改善食品としての有用性を更に高めることができる。植物ステロールとしては、例えばα−シトステロール、β−シトステロール、スチグマステロール、エルゴステロール、カンペステロール等が挙げられる。またこれらの脂肪酸エステル、フェルラ酸エステル、配糖体を用いることもできる。本発明においては、これらを一種以上用いることができる。酸性水中油型乳化物中の、植物ステロールの含有量は、１．２〜１０％、特に２〜５％が好ましい。
【００１３】
水相には、酸性物質以外の成分、すなわち、水；食塩；卵黄；グルタミン酸ソーダ等の調味料；砂糖、水飴等の糖類；酒、みりん等の呈味料；各種ビタミン；香辛料；キサンタンガム、ジェランガム、グァーガム、タマリンドガム、カラギーナン、ペクチン、トラガントガム等の増粘多糖類；馬鈴薯澱粉等の澱粉類、それらの分解物及びそれらの化工澱粉類；水溶性多糖類；ショ糖脂肪酸エステル、ソルビタン脂肪酸エステル、ポリグリセリン脂肪酸エステル、ポリソルベート等の合成乳化剤、大豆タンパク質、乳タンパク質、小麦タンパク質等、あるいはこれらタンパク質の分離物や分解物等のタンパク質系乳化剤、レシチン又はその酵素分解物等の天然系乳化剤；牛乳等の乳製品；各種リン酸塩等を配合することができる。本発明においては、目的とする組成物の粘度、物性等に応じて、これらを適宜配合できる。
【００１４】
本発明において、卵黄は、生、凍結、粉末、加塩、加糖等任意の形態でよく、また卵白を含んだ全卵の形態で配合してもよい。組成物中の卵黄の含有量は、風味向上の観点から、液状卵黄換算で５〜２０％が好ましく、７〜１７％がより好ましく、８〜１５％が特に好ましく、１０〜１５％が最も好ましい。また、卵黄は酵素処理卵黄を用いてもよい。卵黄の酵素処理に用いる酵素としては、エステラーゼ、リパーゼ、ホスホリパーゼが好ましく、リパーゼ、ホスホリパーゼがより好ましく、ホスホリパーゼが特に好ましい。ホスホリパーゼの中でも、ホスホリパーゼＡ、すなわちホスホリパーゼＡ１及び／又はＡ２が最も好ましい。
酵素処理条件は、卵黄の全部に酵素処理卵黄を用いる場合、リゾ比率（全リン脂質中のリゾリン脂質の比率）がリン量基準で１５％以上となるような条件を適宜選択すればよい。具体的には、酵素添加量は、酵素活性が１００００ＩＵ／ｍＬの場合、卵黄に対して０．０００１〜０．１％、特に０．００１〜０．０１％が好ましく、反応温度は２０〜６０℃、特に３０〜５５℃が好ましく、反応時間は１時間〜３０時間、特に５時間〜２５時間が好ましい。また卵黄の一部に酵素処理卵黄を用いる場合、酵素未処理卵黄と酵素処理卵黄の合計のリゾ比率が上記範囲となるように酵素処理条件を選択すればよい。かかる酵素処理は、各原料を混合して乳化処理する以前の段階で行うことが好ましい。
【００１５】
酵素処理卵黄は、酵素処理液をそのまま用いてもよいし、殺菌、凍結、粉末化、加塩、加糖など任意の処理や任意の形態で用いてもよい。また、卵白や全卵を配合してもよい。
【００１６】
また、本発明の酸性水中油型乳化物において、風味及び外観の点で含有する全リン脂質中のリゾリン脂質の比率（以下、リゾ比率と記載する）がリン量基準で１５％以上であるのが好ましく、より好ましくは２５％以上、特に２９〜７５％が好ましい。リゾリン脂質は、その一部又は全部が卵黄や大豆由来であることが好ましく、卵黄由来であることが特に好ましい。
【００１７】
油相と水相の重量比は、１０〜８０：９０〜２０が好ましく、３５〜７５：６５〜２５が特に好ましい。
【００１８】
次に、前記水相と油相を混合した後に、酸性物質を添加してｐＨを１以上低下させる。ここに用いる酸性物質としては、米酢、酒粕酢、リンゴ酢、ブドウ酢、穀物酢、合成酢等の食酢；クエン酸、コハク酸等の有機酸及びその塩；レモン果汁等の各種野菜又は果実の搾汁液等が挙げられる。このうち、食酢を主成分とするのが特に好ましい。なお、酢を含有しない酸性物質は、油相と混合する前の水相に添加することが好ましい。
【００１９】
当該酸性物質は、ｐＨを１以上低下させる量添加すればよく、例えば食酢（１０％酢酸含有）の場合乳化物中に３〜１０％、特に５〜８％となるように添加するのが好ましい。
【００２０】
酸性物質添加後の水相のｐＨは、風味と保存性のバランスの観点から２〜６、特に３〜５が好ましい。
【００２１】
酸性物質添加後は、均一混合乳化を行い予備乳化を完了し、均質化（精乳化）することにより、酸性水中油型乳化物を得ることができる。均質機としては、例えばマウンテンゴウリン、マイクロフルイダイザー等の高圧ホモジナイザー、超音波式乳化機、コロイドミル、アジホモミキサー、マイルダー等が挙げられる。各種原料の混合乳化は、攪拌槽などで行うバッチ式の生産システムと連続的に各種原料を混合機に送る連続式生産システムがあるが、バッチ式システムのほうが効果は高い。また、一般の市販されているマヨネーズの粘度は約１８０Ｐａ・ｓ程度であることから、最終製品となるマヨネーズの粘度も、１６０から２２０Ｐａ・ｓの範囲になるものが好ましい。
【００２２】
本発明方法によれば長期間乳化安定性が保持された酸性水中油型乳化物を得ることができる。当該酸性水中油型乳化物としては、例えば日本農林規格（ＪＡＳ）で定義されるドレッシング、半固体状ドレッシング、乳化液状ドレッシング、マヨネーズ、サラダドレッシング、フレンチドレッシング等が挙げられるが、特にこれらに限定されるものではなく、広くマヨネーズ類、ドレッシング類といわれるものが該当する。
【００２３】
【実施例】
実施例１
表１に示す組成の油相及び水相を次の方法に従って調製した。まず、精製塩、上白糖、グルタミン酸ナトリウム、からし粉、クエン酸を水に分散させたさせたもの（「調味分散水」という。以下同じ。）と酵素処理卵黄を攪拌翼を有するミキサーに添加し、２０℃に温度調整しながら減圧下（２０ｋＰａ）、攪拌翼の最外周速が６ｍ／ｓとなる条件で１５分撹拌処理を行った。次に、２％分の油相（ジグリセリド高含有油）に大豆多糖類を分散させたものをミキサーに添加し、同上の攪拌速度で３分攪拌し均一混合した。次に、攪拌周速を３ｍ／ｓにし残りの油相を攪拌しながら添加した。この時の乳化物のｐＨは５．５であった。その後１０％醸造酢を添加混合し、ｐＨが４．１の予備乳化物を得た。これを、コロイドミル（ＭＺ８０：ＦＲＹＭＡ社製）を使用して４２００ｒ／ｍｉｎ、クリアランス０．２５ｍｍで精乳化し、平均乳化粒子径２．１μｍのマヨネーズを製造した。
【００２４】
比較例１
調味分散水と酵素処理卵黄と食酢を攪拌翼を有するミキサーに添加し、２０℃に温度調整しながら減圧下（２０ｋＰａ）、攪拌翼の最外周速が６ｍ／ｓとなる条件で１５分撹拌処理を行った。次に、２％分の油相（ジグリセリド高含有油）に大豆多糖類を分散させたものをミキサーに添加し、同上の攪拌速度で３分攪拌し均一混合し、攪拌周速を３ｍ／ｓにし残りの油相を攪拌しながら添加し、予備乳化物を得た。これを、実施例１と同じコロイドミルを用い、４２００ｒ／ｍｉｎ、クリアランス０．４５ｍｍで精乳化し、平均乳化粒子径２．８μｍのマヨネーズを製造した。
【００２５】
比較例２
比較例１と同じ配合、装置及び撹拌条件で予備乳化を行い、実施例１と同じコロイドミルを使用し、同じ設定条件で精乳化を行ったが、精乳化時に水中油型から油中水型への転相が起こり、良好なマヨネーズを得ることができなかった。
【００２６】
【表１】
【００２７】
〔酵素処理卵黄の調製〕
食塩濃度１０％の卵黄液７５０ｇ、水１５０ｇ、及び食塩１５ｇを混合し、反応温度で十分予熱した後、卵黄液に対して表２に示す量のホスホリパーゼＡ２を添加し、酵素分解卵黄を得た。反応時間、反応温度、リゾ化率を表１に示す。尚、リゾ化率は以下の方法により算出した。まず反応物をクロロホルム／メタノール（３：１）混合溶媒により繰り返し抽出を行い、反応物中の全脂質を得た。得られた脂質混合物を薄層クロマトグラフィーに供し、一次元＝クロロホルム：メタノール：水（６５：２５：４９）、二次元＝ブタノール：酢酸：水（６０：２０：２０）による二次元薄層クロマトグラフィーにより、各種のリン脂質を分取したリン脂質のリン量を市販の測定キット（過マンガン酸塩灰化法、リン脂質テストワコー、和光純薬工業株式会社製）を用いて算出した。リゾ化率（％）は（リゾリン脂質画分リン合計量／全リン脂質画分リン合計量）×１００により算出した。
【００２８】
【表２】
【００２９】
〔ｐＨ測定法〕
ｐＨメーターに「ＰＨコントローラー ＦＤ−０２（東京ガラス機械社製）」を用い、２０℃で通常の使用方法にて乳化物のｐＨを測定した。
【００３０】
〔安定性評価法〕
マヨネーズ（精乳化物）の乳化安定性の評価は、製造後２０℃で１ヶ月保存したマヨネーズを、５０ｍＬ用の遠心管に３０ｇ精秤し１５０００ｒ／ｍｉｎ、３０ｍｉｎの条件で遠心分離を行った後、上層に遊離した油量を計量し、次式に従ってオイルオフ量として算出した。
オイルオフ量（％）＝遠心分離後の遊離油量（ｇ）／（遠心管に精秤したマヨネーズ量（ｇ）×油相量（６７％））×１００（％）
【００３１】
【表３】
【００３２】
表３から明らかなように、醸造酢を先に添加した場合は予備乳化物の粘度が向上せず、精乳化時にコロイドミルのクリアランスを転相しない範囲とすると乳化粒子が大きくなり、結果として安定性が悪く（比較例１）、また通常のクリアランスとすると転相が生じ（比較例２）、何れも良好な乳化物は得られなかった。一方、醸造酢を後添加した場合、粘度と安定性が顕著に向上していることがわかる。
【００３３】
【発明の効果】
本発明によれば、新たな添加物を添加することなく、乳化安定性の良好で、十分な粘度を有するジグリセリド含有酸性水中油型乳化物を得ることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a diglyceride-containing acidic oil-in-water emulsion having stable and sufficient viscosity of an emulsion system for a long period of time.
[0002]
[Prior art]
In recent years, it has been revealed that diglyceride has an obesity-preventing action, a weight-gain suppressing action, and the like (see Patent Document 1), and attempts have been made to mix it with various foods. And it is reported that if a glyceride mixture containing diglyceride at a high concentration is used for the oil phase, an edible oil-in-water emulsion having a rich taste even when the amount of fat is reduced and having a good flavor can be obtained. (See Patent Document 2).
[0003]
However, acidic oil-in-water emulsions such as mayonnaise in which the oil phase containing a high concentration of diglycerides is emulsified with egg yolk, cracks occur during storage, syneresis is exuded, and the appearance is rough and the texture is rough. It turned out that problems such as becoming occur. As a technique for solving this problem, for example, it has been reported that these problems can be solved by using lysophospholipid as 15% or more (based on phosphorus amount) of the total phospholipid in the acidic oil-in-water emulsion. (See Patent Document 3).
[0004]
[Patent Document 1]
JP-A-4-300828 [Patent Document 2]
Japanese Patent No. 2848849 [Patent Document 3]
JP, 2001-138, A
[Problems to be solved by the invention]
By the way, in order to improve the long-term storage stability of the acidic oil-in-water emulsion of mayonnaise, and to obtain the viscosity required as a product, it is conceivable to increase the amount of a thickener or to add a new additive. The same effect can be obtained when an oil phase containing a high concentration is used. However, there are problems such as loss of flavor and texture.
[0006]
Therefore, the present invention, even when using an oil phase containing a high concentration of diglyceride, without increasing the amount of thickeners and the addition of new additives, stable emulsion system for a long time, sufficient viscosity It is an object of the present invention to provide a method for producing an acidic oil-in-water emulsion having the same.
[0007]
[Means for Solving the Problems]
Therefore, the present inventor has conducted various studies to solve the problems specific to the above-mentioned diglyceride-containing acidic oil-in-water emulsion, and usually mixed with the oil phase after adding the entire amount of the acidic substance to the aqueous phase. Reduce the amount of acidic substances in the aqueous phase component before mixing with the phase to a certain level or less, add the remaining acidic substances such as vinegar after mixing the aqueous phase component and the oil phase, and lower the pH by 1 or more. It has been found that when emulsified by the above, the stability and viscosity are significantly improved. In addition, the effect of improving the stability and viscosity by adding most of the acidic substance at the end is hardly obtained in the acidic oil-in-water emulsion using triglyceride as an oil phase, and is hardly obtained in an acidic water containing an oil phase containing diglyceride. It was also found that the effect was peculiar to an oil-type emulsion.
[0008]
Further, in a large-scale processing at an industrialization level, an aqueous phase and an oil phase are mixed and preliminarily emulsified, followed by a fine emulsification step. However, when the load for raising the viscosity in the fine emulsification step is high, the shear energy becomes too high, and the phase may be changed from the O / W emulsion to the W / O emulsion, and it is difficult to perform stable production for a long time. Become. When ordinary fats and oils (triglycerides) are used as the oil phase, an O / W emulsion is easily formed, so that the phase inversion phenomenon hardly appears. However, when diglycerides are contained in fats and oils, the phase transition is likely to occur because the interfacial tension of oil-water is low and a W / O emulsion is easily formed. Therefore, if this step is adopted, the viscosity of the pre-emulsion increases, so that the load of raising the viscosity in the fine emulsification step can be reduced, resulting in stable production without causing phase inversion, and stable emulsification system for a long time, It was also found that an acidic oil-in-water emulsion having improved viscosity was obtained.
[0009]
That is, the present invention provides a method for producing an acidic oil-in-water emulsion in which an oil containing 20% by weight or more of diglyceride is mixed with an aqueous phase, and an acidic substance is added to lower the pH by 1 or more.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In the method of the present invention, an oil phase containing at least 20% by weight of diglyceride (hereinafter simply referred to as%) and an aqueous phase are mixed. At this time, the point is to suppress the amount of acidic substances added to the aqueous phase before mixing with the oil phase to a certain amount or less. In particular, for vinegar (containing 10% acetic acid) among the acidic substances, the amount added to the aqueous phase is 2% or less, preferably 1% or less, more preferably 0%, based on 100% of the whole system, and the remainder is oil. It is preferably added after mixing with the phase. Here, the oil phase is an oil or fat containing 20% or more of diglyceride, and preferably has a low melting point.
[0011]
The diglyceride also preferably has a low melting point, and specifically, the constituent fatty acid residue preferably has 8 to 24 carbon atoms, particularly preferably 16 to 22 carbon atoms. The amount of unsaturated fatty acid residues is preferably 55% or more, more preferably 70% or more, and particularly preferably 90% or more of the total fatty acid residues. Diglyceride can be obtained by any method such as transesterification of glycerin with vegetable oil, animal oil or the like, or esterification of glycerin with fatty acids derived from the above-mentioned fats and oils. The reaction method may be any of a chemical reaction method using an alkali catalyst or the like, and a biochemical reaction method using an oil hydrolase such as lipase. The diglyceride content in the oil phase of the acidic oil-in-water emulsion of the present invention is preferably at least 20%, more preferably at least 30%, especially at least 35% from the viewpoint of the effectiveness as a lipid metabolism-improving food (suppression of neutral fat accumulation). preferable. The oil phase may contain triglycerides, monoglycerides, free fatty acids and the like in addition to diglycerides. In order to stabilize the emulsion, the oil phase may contain a high melting point fat, especially a fat which is solid at room temperature.
[0012]
The oil phase may further contain a plant sterol having a blood cholesterol lowering effect. The combined use of diglyceride and plant sterol synergistically increases the blood cholesterol lowering effect, and can further enhance the usefulness as a food for improving lipid metabolism. Examples of plant sterols include α-sitosterol, β-sitosterol, stigmasterol, ergosterol, campesterol and the like. In addition, these fatty acid esters, ferulic acid esters, and glycosides can also be used. In the present invention, one or more of these can be used. The content of the plant sterol in the acidic oil-in-water emulsion is preferably 1.2 to 10%, particularly preferably 2 to 5%.
[0013]
The aqueous phase contains components other than acidic substances, ie, water; salt; egg yolk; seasonings such as sodium glutamate; sugars such as sugar and starch syrup; flavors such as sake and mirin; various vitamins; spices; xanthan gum; Guar gum, tamarind gum, carrageenan, pectin, tragacanth gum and the like; starches such as potato starch, their decomposed products and their modified starches; water-soluble polysaccharides; sucrose fatty acid esters, sorbitan fatty acid esters, Synthetic emulsifiers such as polyglycerin fatty acid ester and polysorbate; protein-based emulsifiers such as soybean protein, milk protein, wheat protein and the like, and separated and decomposed products of these proteins; Dairy products; various phosphates and the like. In the present invention, these can be appropriately compounded depending on the viscosity, physical properties, and the like of the target composition.
[0014]
In the present invention, the yolk may be in any form such as raw, frozen, powdered, salted, and sweetened, and may be mixed in the form of whole egg including egg white. The content of egg yolk in the composition is preferably 5 to 20%, more preferably 7 to 17%, particularly preferably 8 to 15%, and most preferably 10 to 15% in terms of liquid egg yolk, from the viewpoint of improving flavor. . The yolk may be enzyme-treated yolk. As the enzyme used for the enzyme treatment of egg yolk, esterase, lipase and phospholipase are preferred, lipase and phospholipase are more preferred, and phospholipase is particularly preferred. Among phospholipase, phospholipase A, that is the most preferred phospholipase A 1 and / or A 2.
When the enzyme-treated egg yolk is used for the whole of the yolk, the conditions for the lyso ratio (the ratio of the lysophospholipid in all the phospholipids) to be 15% or more based on the phosphorus amount may be appropriately selected. Specifically, when the enzyme activity is 10,000 IU / mL, the amount of the enzyme added is preferably 0.0001 to 0.1%, particularly preferably 0.001 to 0.01% with respect to the egg yolk, and the reaction temperature is 20 to 60%. C., preferably 30 to 55.degree. C., and the reaction time is preferably 1 to 30 hours, particularly preferably 5 to 25 hours. When enzyme-treated egg yolk is used as a part of the egg yolk, the enzyme treatment conditions may be selected so that the total lyso ratio of the enzyme-untreated egg yolk and the enzyme-treated egg yolk is within the above range. Such an enzyme treatment is preferably performed at a stage before mixing and emulsifying each raw material.
[0015]
The enzyme-treated egg yolk may use the enzyme-treated solution as it is, or may be used in any treatment or in any form such as sterilization, freezing, pulverization, salt addition, and sugar addition. Egg white or whole eggs may be blended.
[0016]
Further, in the acidic oil-in-water emulsion of the present invention, the ratio of lysophospholipids in the total phospholipids contained in terms of flavor and appearance (hereinafter, referred to as lyso ratio) is 15% or more based on the phosphorus amount. Is more preferable, more preferably 25% or more, and particularly preferably 29 to 75%. The lysophospholipid is preferably partially or entirely derived from egg yolk or soybean, and particularly preferably derived from egg yolk.
[0017]
The weight ratio of the oil phase to the aqueous phase is preferably from 10 to 80:90 to 20, and more preferably from 35 to 75:65 to 25.
[0018]
Next, after mixing the water phase and the oil phase, an acidic substance is added to lower the pH by one or more. Examples of acidic substances used here include vinegar such as rice vinegar, sake lees vinegar, apple vinegar, grape vinegar, grain vinegar, and synthetic vinegar; organic acids and salts thereof such as citric acid and succinic acid; various vegetables and fruits such as lemon juice Juice and the like. Among them, vinegar is particularly preferable. The acidic substance not containing vinegar is preferably added to the aqueous phase before being mixed with the oil phase.
[0019]
The acidic substance may be added in such an amount as to lower the pH by 1 or more. For example, in the case of vinegar (containing 10% acetic acid), it is preferable to add the acidic substance so that it becomes 3 to 10%, particularly 5 to 8% in the emulsion. .
[0020]
The pH of the aqueous phase after the addition of the acidic substance is preferably from 2 to 6, particularly preferably from 3 to 5, from the viewpoint of the balance between flavor and storage stability.
[0021]
After the addition of the acidic substance, the mixture is uniformly mixed and emulsified to complete the preliminary emulsification and homogenized (finely emulsified) to obtain an acidic oil-in-water emulsion. Examples of the homogenizer include a high-pressure homogenizer such as mountain gourin and microfluidizer, an ultrasonic emulsifier, a colloid mill, an azihomomixer, and a milder. For mixing and emulsifying various raw materials, there are a batch-type production system in which a stirring tank or the like is used and a continuous-type production system in which various raw materials are continuously sent to a mixer. The batch-type system is more effective. Further, since the viscosity of general commercially available mayonnaise is about 180 Pa · s, it is preferable that the viscosity of mayonnaise as a final product is also in the range of 160 to 220 Pa · s.
[0022]
According to the method of the present invention, it is possible to obtain an acidic oil-in-water emulsion in which the emulsion stability is maintained for a long time. Examples of the acidic oil-in-water emulsion include, but are not limited to, dressing, semi-solid dressing, emulsified liquid dressing, mayonnaise, salad dressing, French dressing, etc. as defined by the Japanese Agricultural Standards (JAS). It is not something that is widely referred to as mayonnaise or dressing.
[0023]
【Example】
Example 1
An oil phase and an aqueous phase having the compositions shown in Table 1 were prepared according to the following method. First, a purified salt, white sugar, sodium glutamate, mustard powder, and citric acid dispersed in water (hereinafter referred to as “seasoning dispersion water”; the same applies hereinafter) and an enzyme-treated egg yolk are added to a mixer having a stirring blade. Then, while controlling the temperature at 20 ° C., a stirring treatment was performed for 15 minutes under reduced pressure (20 kPa) under the condition that the outermost peripheral speed of the stirring blade was 6 m / s. Next, a soybean polysaccharide dispersed in a 2% oil phase (oil containing a large amount of diglyceride) was added to the mixer, and the mixture was stirred at the same stirring speed for 3 minutes and uniformly mixed. Next, the stirring peripheral speed was set to 3 m / s, and the remaining oil phase was added while stirring. The pH of the emulsion at this time was 5.5. Thereafter, 10% brewed vinegar was added and mixed to obtain a pre-emulsion having a pH of 4.1. This was finely emulsified using a colloid mill (MZ80: manufactured by FRYMA) at 4200 r / min with a clearance of 0.25 mm to produce mayonnaise having an average emulsified particle diameter of 2.1 μm.
[0024]
Comparative Example 1
Add the seasoning dispersion water, enzyme-treated egg yolk and vinegar to a mixer having stirring blades, and stir for 15 minutes under reduced pressure (20 kPa) while adjusting the temperature to 20 ° C. under conditions where the outermost peripheral speed of the stirring blades is 6 m / s. Was done. Next, a soybean polysaccharide dispersed in an oil phase (oil containing a large amount of diglyceride) of 2% was added to a mixer, and the mixture was stirred at the same stirring speed for 3 minutes and uniformly mixed, and the stirring peripheral speed was 3 m / s. The remaining oil phase was added with stirring to obtain a pre-emulsion. This was finely emulsified using the same colloid mill as in Example 1 at 4200 r / min with a clearance of 0.45 mm to produce mayonnaise having an average emulsified particle size of 2.8 μm.
[0025]
Comparative Example 2
Pre-emulsification was carried out under the same composition, equipment and stirring conditions as in Comparative Example 1, and the same colloid mill was used as in Example 1, and fine emulsification was performed under the same setting conditions. Phase inversion occurred, and good mayonnaise could not be obtained.
[0026]
[Table 1]
[0027]
(Preparation of enzyme-treated egg yolk)
Salt concentration of 10% egg yolk solution 750 g, water 150 g, and mixed salt 15 g, was preheated sufficiently at the reaction temperature, adding the amount of phospholipase A 2 as shown in Table 2 with respect to liquid egg yolk, to obtain enzymatic decomposition yolk Was. Table 1 shows the reaction time, reaction temperature, and lyso conversion. The lyso conversion was calculated by the following method. First, the reaction product was repeatedly extracted with a mixed solvent of chloroform / methanol (3: 1) to obtain all lipids in the reaction product. The obtained lipid mixture was subjected to thin-layer chromatography, and one-dimensional = chloroform: methanol: water (65:25:49), two-dimensional = two-dimensional thin-layer chromatography using butanol: acetic acid: water (60:20:20). The amount of phosphorus in the phospholipids obtained by fractionating various phospholipids was calculated by using a commercially available measurement kit (permanganate ashing method, phospholipid test Wako, manufactured by Wako Pure Chemical Industries, Ltd.). The lysolation ratio (%) was calculated by (total amount of phosphorus in lysophospholipid fraction / total amount of phosphorus in total phospholipid fraction) × 100.
[0028]
[Table 2]
[0029]
(PH measurement method)
Using "PH Controller FD-02 (manufactured by Tokyo Glass Machinery Co., Ltd.)" as a pH meter, the pH of the emulsified product was measured at 20 ° C by a usual use method.
[0030]
(Stability evaluation method)
Evaluation of emulsification stability of mayonnaise (finely emulsified product) was performed after 30 g of mayonnaise stored at 20 ° C. for one month after production was precisely weighed in a 50 mL centrifuge tube, and centrifuged at 15000 r / min for 30 min. The amount of oil released to the upper layer was measured and calculated as an oil-off amount according to the following equation.
Oil-off amount (%) = free oil amount after centrifugation (g) / (mayonnaise amount (g) precisely weighed in a centrifuge tube × oil phase amount (67%)) × 100 (%)
[0031]
[Table 3]
[0032]
As is clear from Table 3, when brewed vinegar is added first, the viscosity of the pre-emulsion does not improve, and when the clearance of the colloid mill is set so as not to invert the phase during the fine emulsification, the emulsified particles become large, resulting in stable The properties were poor (Comparative Example 1), and phase inversion occurred with normal clearance (Comparative Example 2), and no good emulsion was obtained in any case. On the other hand, when the brewed vinegar is added later, it is found that the viscosity and the stability are significantly improved.
[0033]
【The invention's effect】
According to the present invention, a diglyceride-containing acidic oil-in-water emulsion having good emulsion stability and sufficient viscosity can be obtained without adding a new additive.
