JP4407788B2 - Sterilization packaging method for shellless raw eggs - Google Patents

Description

【００１１】
次いで、中川らにより示されている殻付き生卵の殻付き卵のｐＨ経時変化のデータ（文献：養鶏の友 No.332, P36-40, 1989、Egg Science and Technology, W.J. Stadelman, 1955）を基に、上記と同様な方法により１日後、３日後、７日後、１４日後のそれぞれのｐＨ値からそれぞれの時点における残存炭酸ガス量を計算して求めた。その結果を図４における線図ａに示す。
【００１２】
図４の線図ａに示すように、経時日数に対する残存炭酸ガス量の変化曲線が、図３に示す経時日数に対するハウユニットと略同様な傾向にあることが確認された。このことから、生卵の鮮度と炭酸ガス放出量は密接な関係があり、殻から出した生卵であっても、その卵白からの炭酸ガスの放出を少なくとも殻付き卵のままで放出する放出量よりも少なくなるように（即ち、図４に示すグラフにおいて、経時日数―残存炭酸ガス量変化曲線が殻付き生卵の場合の線図ａよりも上方にくるように）制御することができれば、殻付き卵のままよりも鮮度よく保存することが可能であることが分かる。
【００１３】
ところで、生卵の殻は、卵殻に９〜２９μｍの気孔が存在し、さらにその内側に細孔０．５〜１μｍを有する２層の卵殻膜が存在する構造となっており、これらの細孔及び気孔を通して外部の炭酸ガス濃度に対応して炭酸ガス及び水分を放出している。そのため、その炭酸ガス透過機構がプラスチック容器の場合と異なり、直接計算では求めることはできないので、上記生卵の殻に対応する要件を満たすプラスチック容器の条件を上記結果から直接得ることはできない。そこで、本発明者らは、種々の材料で生卵充填容器を試作し、上記生卵の経時日数−残存炭酸ガス量との関係と同様な関係を有する生卵充填容器を実験により求めた。その結果、後述する条件のもとで、１５０μｍ厚さのポリプロピレンで製作した容器の場合が、図４に線図ｂで示すように、生卵の場合と殆ど同様な関係を有することを発見した。ポリプロピレンの炭酸ガス透過度は、分圧差１ａｔｍで８５００ｍｌ／２５μｍ・ｍ^２・24hrであるから、この容器の単位炭酸ガス透過量は、１４１７ｍｌ／ｍ^２・24hr（分圧差１ａｔｍ）であった。したがって、この単位炭酸ガス透過量を基準にして、単位炭酸ガス透過量がそれ以下の容器であれば、上記課題を満たす容器を得ることができる。
【００１４】
本発明は、上記知見に基づきなされたもので、本発明で得られた無殻包装卵は、生卵を無殻状態で収容する収容部からなる容器本体と、該容器本体の開口部を覆う蓋材からなる生卵無殻包装用容器に密封包装された無殻包装生卵であって、前記容器本体及び／又は前記蓋材は透視可能な合成樹脂材料で形成され、単位炭酸ガス透過量が高圧側と低圧側の気体分圧差１ａｔｍ換算で、１４１７ｍｌ／ｍ^２・24hr以下となるように形成され、有殻状態で殻外周面を洗浄し且つ殻を殺菌した生卵を無菌雰囲気内で割り、無菌雰囲気で洗浄殺菌済みの前記容器本体の収容部に充填・密封され、生卵の卵白の盛り上がり状態を新鮮な状態に維持して外部より観察できるようにしてなる無菌化充填無殻包装生卵であることを特徴とするものである。
【００１５】
前記炭酸ガス透過量の条件を満たすには、容器本体及び／又は蓋材は、炭酸ガス透過度が８５００ｍｌ／ｍ^２・24hr・atm／２５μｍより小さい合成樹脂材料で構成されていることが望ましい。このような条件を満たすものであれば、容器本体及び／又は前記蓋材の材料は特に限定されないが、例えば、ＰＥＴ等のポリエステル系樹脂、ナイロン等のポリアミド系樹脂、エチレンビニルアルコール共重合体等のポリビニルアルコール系樹脂、塩化ビニル系樹脂、塩化ビニリデン系樹脂、フッ素系樹脂などから選択される一種の単層または複数の組み合わせからなる複合材が採用できる。その包装形態も特に限定されないが、容器本体は、殻から出した生卵を１個づつ充填し、外部からその状態が個々に観察できるようになっているのが望ましく、透明又は半透明な材料で形成され、複数の収容部が蓋材シール部の一部で互いに隣接する収容部と連結されて一体に構成され、連接部で切断することによって個々の密封収容部に切り離し可能に構成しているのが望ましい。そして、その包装は、無殻生卵が無菌雰囲気で充填・密封された無菌化充填無殻包装生卵であること、及び又は無殻生卵の充填時に容器本体の収容部に炭酸ガスを供給してヘッドスペースのガスを炭酸ガス置換して包装することによって、より高品位の無殻包装生卵を得ることができる。
【００１６】
また、無殻包装生卵を得る本発明の無殻包装生卵の無菌化包装方法は、生卵を有殻状態で殻外周面を洗浄殺菌する殻付き卵洗浄殺菌工程、生卵を無殻状態で収容する収容部と蓋材シール部とからなり、透視可能な合成樹脂材料で形成され、単位炭酸ガス透過量が高圧側と低圧側の気体分圧差１ａｔｍ換算で、１４１７ｍｌ／ｍ^２・24hr以下となるように形成された容器本体の内周面及び外周面を洗浄殺菌する容器本体洗浄殺菌工程、有殻状態で殻外周面を洗浄し且つ殻を殺菌した生卵を無菌雰囲気内で割り、洗浄殺菌済み容器本体の収容部に充填する生卵無殻無菌化充填工程、無殻生卵充填済みの容器本体の収容部を蓋材でシールして密封する密封工程からなり、無殻の生卵の卵白の盛り上がり状態を新鮮な状態に維持して外部より観察でき、且つリゾチームの抗菌活性効果の低下を抑制するように包装してなることを特徴とするものである。前記生卵無菌化充填工程は、必要に応じて所定濃度の炭酸ガス無菌雰囲気で行われ、容器本体内の空気を所定置換率で炭酸ガスに置換して包装する。炭酸ガス置換率は、１０〜８８％の範囲内が望ましい。
【００１７】
【発明の実施の形態】
以下、本発明の実施形態に係る無殻包装生卵の実施形態を図面を基に詳細に説明する。
図１及び図２は、本発明の実施形態に係る無殻包装生卵パックを示し、図１はその斜視図、図２は図１のＡ−Ａ断面図である。
無殻包装生卵パック１は、単位パック５が容器本体２と蓋材３とからなり、図の実施形態では容器本体２が卵１個つづ収容可能な単位パック５が６個連接して構成されている。各単位パック５は、家庭用冷蔵庫の卵入れにそのまま収納できるように、下方が半球状となって上方が開口している円筒部からなる収容部６と、開口部外周面に形成された蓋材シールフランジ７とから構成され、隣接する各単位パック５が互いにフランジの接線部近傍が繋がって連通部８となり、該連接部を介して一体成形して構成されている。一方、蓋材３は、後述する密封工程で蓋材フィルムが蓋材シールフランジ７及び連通部８にヒートシールされ、蓋材シールフランジ７から外方にはみ出す部分は、ヒートシール工程と同時又は後工程で切断除去され、図示のように、単位パックの開口部を覆って連通部８を介して連通している。なお、図中９は卵の黄身、１０は卵の白身を表している。さらに蓋材は成形蓋であってもよい。
【００１８】
上記容器本体２及び蓋材３の材質は、容器内に密封された無殻生卵を、▲１▼殻付き生卵の場合よりもその炭酸ガス保持の経時的減少が少なくなるように保持できる条件を満たすものでなければならず、且つ▲２▼内部に収納した生卵の状態が外部より観察できるように透視可能でなければならない。上記▲１▼の条件を満たすものとして、本発明では生卵を充填密封した状態で、容器の単位炭酸ガス透過量が、高圧側と低圧側の気体分圧差１ａｔｍ換算で、１４１７ｍｌ／ｍ^２・24hr以下となるようにその容器を構成した。単位炭酸ガス透過量が、１４１７ｍｌ／ｍ^２・24hr以上であると、生卵の殻と比較して炭酸ガスバリヤ性に劣り、殻付き生卵以上のＨＵ値抑制効果を得れないので、それ以下、望ましくは１４０ｍｌ／ｍ^２・24hr以下である。そして、その条件を満たす材料として、炭酸ガス透過度が８５００ｍｌ／ｍ^２・24hr以下で、且つ内部が透視可能な透明又は半透明の材料を選択した。
【００１９】
上記条件を満たす材料としては、ＰＥＴ、ポリ塩化ビニル、エチレンビニルアルコール共重合体等を含む単層又は多層材料が採用できる。容器本体は、これらの材料から射出成形し、蓋材はこれらの材料からなるフィルムで構成されるが、容器本体と蓋材は必ずしも同じ材料とは限らず、異種材料の組合せでも良いが、蓋材と容器本体のシール面は易ヒートシール性の材料で構成するのが望ましい。
【００２０】
上記無殻包装パックは、無菌化無殻包装パックにすることによって、充填包装時の無菌化とその後の細菌侵入阻止により、殻付き生卵と比べてより微生物的に安全であり、低温流通で新鮮卵の長期間の流通を可能にする。無菌化包装パックの製造は、まず、生卵を有殻状態で殻外周面を洗浄し且つ殻を殺菌する。一方、容器本体の内周面及び外周面は、容器本体洗浄殺菌工程にて殺菌し、蓋材は蓋材殺菌工程で殺菌しておく。そして、前記洗浄殺菌済み生卵を無菌雰囲気内で割り、洗浄殺菌済み容器本体の収容部に充填し、次いでヘッドスペースの空気を無菌化した炭酸ガスで置換して蓋材をヒートシールすることによって、無殻生卵充填済みの容器本体の収容部を密封して無殻無菌化包装生卵を得る。それらの各工程は、何れも雰囲気空気を清浄化した無菌化ブース内で行われるが、各工程のブース間の空気の流れを阻止するように工夫することによって、例えば殻付き卵洗浄殺菌工程、容器本体洗浄殺菌工程及び蓋材殺菌工程が行われるブース内の空気が充填工程及び密封工程の行われるブース内に流入することを防止することによって、より無菌化の高い無殻無菌化包装生卵を得ることができる。
【００２１】
【実施例】
本発明の作用効果を確認するために、底部がドーム形状の容器本体からなる卵１個充填用の単位容器のみからなる容器本体をＰＥＴで蓋材はアルミ箔積層体を用いて複数個製作した。容器本体及び蓋材の各寸法は次の通りである。
容器：
開口口部直径 ４．３３ｃｍ
底部ドーム部半径 ２．０ ｃｍ
高さ ５．５ ｃｍ
容器体積 ７０．３ ｃｍ^３
表面積（全体） ８７．４ ｃｍ^２
表面積（蓋部） １４．７ ｃｍ^２
表面積（胴部） ７２．７ ｃｍ^２
胴部肉厚 ０．１５ｍｍ
上記容器に、卵重６０ｇ、体積５２．２ｃｍ^３の卵を無殻状態でそれぞれ充填密封した。各容器に充填する生卵は、測定開始時にそれに含まれている初期炭酸ガス量が各卵とも同じとなるように、前述のように炭酸ガス置換したアルミ箔積層フィルムで製作した袋内に密封して１週間保存したものを使用した。蓋材はアルミ箔積層フィルムを用いた。したがって、この場合、蓋材からの炭酸ガス透過はなく、炭酸ガスは専ら容器本体から透過するとみなされる。
【００２２】
以上のようにして得た無殻包装生卵を室内に保管温度２５℃で保存し、包装直後、１日経過後、３日経過後、７日経過後及び１４日経過後に、それぞれ容器から出してＨＵ値を測定した。また、比較例として容器本体がＰＰからなる他は、上記各寸法が前記実施例と全く同様になるように作製された容器に上記条件と同じ無殻生卵を充填密封して無殻包装生卵を製造し、同様にして所定日数経過ごとにＨＵ値を測定して、ハウユニットの経時変化を調べた。その結果を前述した殻付き卵の場合一緒に図３に示す。図３において、線図ｃが、ＰＥＴで製造した実施例であり、その場合は図から明らかなように、ハウユニットの経時変化は殆どなく、１４日経過後でも僅かな減少しか認められず、殻付き生卵の場合と比べて明らかに鮮度保持に優れていることが分かる。これに対して、比較例のＰＰで形成された容器の場合(線図ｂ)は、殻付き卵と比べて経時変化は少ないが、ＨＵ値減少抑制効果が少なかった。
【００２３】
次に、これら容器入り生卵の残存炭酸ガス量の経時変化を調べた。容器内の炭酸ガス濃度が大気中の炭酸ガス濃度とつりあうまで容器内から外部へ炭酸ガスの透過によって残存炭酸ガス量は漸減していくが、容器からの炭酸ガス透過量は容器内と大気中の炭酸ガス分圧差によって影響されるので、実測が困難であるため、実験では次の計算式に基づきコンピュータシミュレーションによって、容器内の残存炭酸ガス量の経時変化を調べた。
プラスチック容器の場合、容器内の逐次的な炭酸ガス濃度は、次式で表すことができる。
ＣＡ（ｎ＋１）＝ＣＡ（ｎ）＋ΔＱ／Ｖ（ｎ） （２）
ここで、ＣＡ（ｎ＋１）：一定時間後の炭酸ガス濃度
ＣＡ（ｎ）：ある時間における炭酸ガス濃度
ΔＱ：ある時間における炭酸ガス透過量
Ｖ（ｎ）：ある時間におけるヘッドスペース体積
また、容器の炭酸ガス透過量は、次式で表すことができる。
ΔＱ＝Ｒ×Ｓｑ×（Ａｃｏ_２−Ｐｃｏ_２） （３）
ここで、Ｒ ：炭酸ガス透過度
Ｓｑ：容器透過面積
Ａｃｏ_２：大気中炭酸ガス分圧
Ｐｃｏ_２：ある時間における容器内炭酸ガス分圧
【００２４】
そこで、容器内炭酸ガス量は、ある一定時間（本実験では１２時間）ごとに容器内炭酸ガス濃度を計算し、その時間内に透過した炭酸ガス量を逐次加算することにより求めた。その結果を図４に示す。その結果、材質がＰＰである比較例の場合は、経時日数に対する残存炭酸ガス量の変化が、図示に示すように、略一致している。この場合、比較例の単位炭酸ガス透過量は次式で計算することができる。

したがって、比較例が殆ど殻付き生卵の場合と一致値していることを考慮すれば、この単位炭酸ガス透過量を基準にして、単位炭酸ガス透過量がそれ以下であれば良いことが分かる。また、容器本体をＰＥＴで製作した比較例の場合は、単位炭酸ガス透過量は、５７ｍｌ／ｍ^２・24hr(分圧差１ａｔｍ)であった。そして、この場合は、図示のように、経時日数に対する残存炭酸ガス量の低下も僅かであった。そして、ハウユニットの経時変化も図３の線図（ｃ）に示すように、殻付き卵と比べて殆ど減少が少なく、鮮度保持に特段の効果があることが確認された。なお、実施例及び比較例の場合、経時変化に対してハウユニットが増大して部分が見られるが、それは次のような原因によると推測される。生卵の場合は殻から水分透過があるため、重量変化があり、その都度の重量に基づいて測定している。しかしながら、実施例及び比較例の場合、水分の透過がないため重量変化がないので初期の殻付き生卵の重量で計算したことによる誤差のために生じたと推測される。
【００２５】
以上、本発明の実施形態及び実施例について説明したが、本発明は上記実施例にかぎるものでなく、その技術的思想の範囲内で種々の設計変更が可能である。例えば、上記実施形態では容器本体の収納部には生卵１個だけ充填するようにしたが、各収容部への充填個数は任意であり、それに合わせて収容部の大きさを選択することができる。また、単位炭酸ガス透過量が前記条件を満足するものであれば、その材質や肉厚は特に限定されない。
【００２６】
【発明の効果】
以上のように、本発明によれば、生卵を単位炭酸ガス透過度が卵の殻よりも少ない透明又は半透明の容器に無殻状態で充填密封することによって、生卵の鮮度を長期間に亘って維持できて商品価値を高めることができるとともに、生卵の白身や黄味状態が外部から直接判別できるので、消費者はその鮮度を確認して安心して購入することができる。また、上記包装により、卵の白身に多く含まれているリゾチームが最も強い抗菌活性を示す中性領域にｐＨ値を維持することができ、リゾチ−ムの抗菌活性の低下を抑制することができる。さらに、無菌化包装することによって、殻付き生卵に比べて細菌に汚染されるおそれがなく、安心である。さらに、容器包装であるので、流通段階での取り扱いも容易である。また、殻がないので調理に際して殻を割る必要がなく、中身の取り出しが容易であり、且つその都度殻の廃棄物が発生しないなどの格別な効果を奏するものである。
【図面の簡単な説明】
【図１】本発明の実施形態に係る無殻包装生卵の斜視図である。
【図２】そのＡ−Ａ断面図である。
【図３】殻付き生卵及び無殻包装生卵におけるハウユニットの経時日数に対する変化を示す線図である。
【図４】殻付き生卵及び無殻包装生卵における残存炭酸ガス量の経時日数に対する変化を示す線図である。
【図５】ｐＨ値から炭酸ガス初期値を推定するための水素イオン−炭酸ガス量線図である。
【符号の説明】
１ 無菌包装生卵パック ２ 容器本体
３ 蓋材 ５ 単位パック
６ 収容部 ７ 蓋材シールフランジ
８ 連通部 ９ 黄身
１０ 白身[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sterilization method of packaging a shell-less packaging raw eggs it possible to circulate while maintaining the freshness for a long time in a state of being sealed observable container externally out fresh raw egg from the shell .
[0002]
[Prior art]
Conventionally, raw eggs are packed in plastic packs or pulp slurry molding packs with shells, and are distributed so as to protect the shells from cracking. However, since these containers do not have rigidity, there is a problem that care is taken in handling such as transportation. In addition, since the contents cannot be observed from the outside in a shelled state, consumers cannot find a defective egg until it breaks the egg, or the storage period of raw eggs is about several days, and the storage period is short There was a problem such as. In order to solve these problems, eggs in a packaging container in which the shell is removed from the egg and only the contents are contained in a plastic container and sealed are proposed (for example, Japanese Patent Laid-Open No. 2001-301860, Japanese Patent Laid-Open No. 1). No. 199809, JP-A 63-185353).
[0003]
The proposed shellless packaged raw eggs are sealed without providing a headspace during packaging, sealed by replacing the air in the headspace with an inert gas, or evacuated from the housing or doubled out of the container. By sealing the gap with a vacuum, the oxygen in the container is removed to increase the shelf life of the egg.
[0004]
[Problems to be solved by the invention]
By the way, in the case of raw eggs with shells, the carbon dioxide contained in the eggs is released from the pores of the eggshell as time elapses, and the pH value of the egg white rises, resulting in a decrease in the thick egg white. It is known that watery egg white increases and the antibacterial activity of lysozyme contained in egg white decreases. Therefore, a fresh egg can know the freshness degree of the egg by observing the rising state of egg white. From that point of view, conventionally, a how unit value (hereinafter referred to as HU value) calculated from the weight of the egg and the height of the thick egg white is generally known as an index indicating the freshness of the egg.
[0005]
Therefore, if the HU value can be kept high, the freshness of the egg can be maintained. Therefore, when the raw egg is distributed from the shell and packaged in a container, the freshness of the raw egg should be maintained as long as the HU value can be reduced as compared with the case where the raw egg is distributed in a shelled state. Can increase the commercial value of eggs. However, all of the above conventional shellless packaged eggs in a container are capable of long-term storage by removing oxygen in the container and ensuring a barrier property against oxygen in the container to prevent oxidative degradation of raw eggs. It has been made from a viewpoint, and no one based on the technical idea of the effect of suppressing the decrease in the HU value of a raw egg from a conventional shell has been proposed yet. For this reason, the conventional shellless packaged eggs in a container have not been able to satisfactorily exhibit the effect of maintaining the fresh state of the egg whites of raw eggs and suppressing the decrease in the antibacterial activity of lysozyme.
[0006]
Therefore, the present invention is intended to solve the above-mentioned problems in conventional shellless packaged eggs in containers, can maintain a high HU value by maintaining a fresh state of egg white of raw eggs, and and to provide a sterilization method of packaging containers shell-packaging eggs can be maintained for a long time an effect of suppressing the decrease of the antimicrobial activity of lysozyme.
[0007]
[Means for Solving the Problems]
The present inventor paid attention to the relationship between the decrease in the HU value of shelled raw eggs and the amount of carbon dioxide gas released in the research for obtaining the unshelled packaged eggs in a container that has the effect of suppressing the decrease in the HU value to solve the above problems Then, the relationship between the change in the number of days elapsed and the HU value of the raw eggs with shells, and the change in the number of days elapsed with the raw eggs in shells and the amount of residual carbon dioxide gas was examined.
At that time, the inside of the bag formed of the aluminum foil laminated film is replaced with carbon dioxide so that all the shelled raw eggs can start from the same conditions, and the shelled eggs are sealed in the bag and stored for one week. Thus, the carbon dioxide replacement rate in all eggs was made constant. Then, it preserve | saved in air | atmosphere with a temperature of 22 degreeC and a humidity of 60%, and measured HU value immediately after preservation | save after 1 day, 3 days, 7 days, and 14 days. The HU value was obtained by actually measuring H (m) and W (g), and using the following simplified formula.
HU value = 100 × log (H−1.7W ^0.37 + 7.6) (1)
However, H (m): Thick egg white height 2 (cm) away from the yolk in the major axis direction W (g): Egg weight The result is shown by a diagram a in FIG. As shown in the figure, the HU value was 77.2 at the start of actual measurement, but decreased inversely according to the number of days elapsed. Particularly, the freshness decreased sharply by the seventh day of age. I understand that.
[0008]
Next, the relationship between the number of days elapsed and the amount of carbon dioxide released in the egg was examined on the assumption that the cause of the decrease in HU value, that is, the decrease in freshness was correlated with the amount of carbon dioxide released from the raw eggs. The amount of carbon dioxide released from a shelled raw egg can be determined by measuring the amount of carbon dioxide remaining for each elapsed time of the shelled raw egg, but it is difficult to directly measure the amount of carbon dioxide released from the shelled raw egg. Therefore, the initial pH value at the start of measurement was measured by the following method, and the initial amount of carbon dioxide was estimated from the measured value of pH 7.00.
[0009]
The relationship between the pH in the egg, the bicarbonate ion concentration, and the carbonate ion concentration when the CO2 environmental concentration is changed is clarified by Brooks and Pace et al. (Reference: Proc. Royal. Soc. London, Ser. B126 196-210, 1938) From this relationship, based on the raw test egg data shown in Table 1, the amount of carbon dioxide ionized in the egg and the amount of hydrogen ions in the egg are obtained by calculation, as shown in FIG. From the results, the initial carbon dioxide gas amount of 1.17 cc / piece of the test egg was determined.
[0010]
[Table 1]

[0011]
Next, the data of changes in the pH of shelled eggs of shelled raw eggs shown by Nakagawa et al. (Reference: Chicken Friend No.332, P36-40, 1989, Egg Science and Technology, WJ Stadelman, 1955) Based on the same method as described above, the amount of residual carbon dioxide gas at each time point was calculated from each pH value after 1 day, 3 days, 7 days, and 14 days. The result is shown in the diagram a in FIG.
[0012]
As shown in the diagram a of FIG. 4, it was confirmed that the change curve of the amount of residual carbon dioxide gas with respect to the number of elapsed days has a tendency similar to that of the how unit with respect to the elapsed days shown in FIG. For this reason, the freshness of raw eggs and the amount of carbon dioxide released are closely related, and even a raw egg released from a shell releases carbon dioxide from the egg white at least as a shelled egg. If it can be controlled to be less than the amount (that is, in the graph shown in FIG. 4, the change in the number of days elapsed—the remaining carbon dioxide amount change curve is above the diagram a in the case of a shelled raw egg) It can be seen that it can be preserved better than a shelled egg.
[0013]
By the way, the shell of the raw egg has a structure in which the pores of 9 to 29 μm are present in the eggshell, and two layers of eggshell membranes having pores of 0.5 to 1 μm are present on the inside thereof. In addition, carbon dioxide gas and moisture are released through the pores in accordance with the external carbon dioxide gas concentration. Therefore, unlike the case of the plastic container, the carbon dioxide permeation mechanism cannot be obtained by direct calculation, so the condition of the plastic container that satisfies the requirements corresponding to the raw egg shell cannot be obtained directly from the above result. Therefore, the present inventors made a prototype of a raw egg filling container using various materials, and experimentally obtained a raw egg filling container having a relationship similar to the relationship between the number of days elapsed of the raw egg and the amount of residual carbon dioxide. As a result, it was discovered that under the conditions described later, a container made of polypropylene having a thickness of 150 μm has almost the same relationship as that of a raw egg as shown by a line b in FIG. . Since the carbon dioxide gas permeability of polypropylene is 8500 ml / 25 μm · m ² · 24 hr at a partial pressure difference of 1 atm, the unit carbon dioxide gas permeability of this container was 1417 ml / m ² · 24 hr (partial pressure difference of 1 atm). Therefore, if the unit carbon dioxide permeation amount is a container having a unit carbon dioxide permeation amount lower than the unit carbon dioxide permeation amount, a container satisfying the above-described problems can be obtained.
[0014]
The present invention has been made on the basis of the above knowledge, and the shellless packaged egg obtained in the present invention covers a container body composed of a housing part for housing raw eggs in a shellless state, and an opening of the container body. A shellless packaged raw egg hermetically packaged in a raw egg shellless packaging container made of a lid, wherein the container body and / or the lid is formed of a transparent synthetic resin material and has a unit carbon dioxide gas permeation amount There a gas partial pressure difference 1atm conversion high pressure side and low pressure side, is formed to be equal to or less than 1417ml / m 2 ^· 24hr, raw egg was sterilized washed and shells shells outer peripheral surface in a closed shell condition in a sterile atmosphere The sterilized filled shellless packaging that is filled and sealed in the container body container that has been split and cleaned and sterilized in a sterile atmosphere so that the swelled state of raw egg white can be kept fresh and can be observed from the outside. It is characterized by being a raw egg.
[0015]
In order to satisfy the condition of the carbon dioxide permeation amount, it is desirable that the container main body and / or the lid material be made of a synthetic resin material having a carbon dioxide gas permeability of less than 8500 ml / m ² · 24 hr · atm / 25 μm. As long as these conditions are satisfied, the material of the container body and / or the lid is not particularly limited. For example, polyester resins such as PET, polyamide resins such as nylon, ethylene vinyl alcohol copolymers, and the like A composite material composed of a single layer or a combination of plural types selected from polyvinyl alcohol resins, vinyl chloride resins, vinylidene chloride resins, fluorine resins, and the like can be employed. Although the packaging form is not particularly limited, it is desirable that the container body is filled with raw eggs taken out of the shell one by one, and the state can be individually observed from the outside. Transparent or translucent material A plurality of accommodating portions are integrally formed by being connected to adjacent accommodating portions at a part of the lid seal part, and can be separated into individual sealed accommodating portions by cutting at the connecting portions. It is desirable. The packaging is a sterilized filled shellless raw egg filled and sealed in a sterile atmosphere and / or carbon dioxide gas is supplied to the container body container when filling the shellless raw egg. Then, by replacing the headspace gas with carbon dioxide gas and wrapping it, a higher quality shellless raw egg can be obtained.
[0016]
Moreover, the sterilization packaging method for shellless packaged raw eggs of the present invention for obtaining shellless packaged raw eggs is a shelled egg cleaning and sterilization process for cleaning and sterilizing the outer peripheral surface of shells in a shelled state, It is made of a synthetic resin material that can be seen through. The unit carbon dioxide gas permeation amount is 1417 ml / m ² · 24 hr in terms of gas partial pressure difference of 1 atm between the high pressure side and the low pressure side. A container body cleaning and sterilization process for cleaning and sterilizing the inner and outer peripheral surfaces of the container body formed as follows, and the raw eggs with the shell outer surface cleaned and sterilized in a shelled state are divided in a sterile atmosphere. , raw egg shell-sterilized filling step of filling the housing portion of the washing sterilized container body, the housing portion of the shell-live egg filled container body consists sealing step of sealing by sealing with a lid member, the Mukara Keep the swell of fresh egg white fresh and observe from outside And it is characterized in by comprising and packaged so as to suppress a reduction in antimicrobial activity effect of lysozyme. The raw egg sterilization filling step is performed in a carbon dioxide gas aseptic atmosphere of a predetermined concentration as necessary, and the air in the container body is replaced with carbon dioxide gas at a predetermined replacement rate and packaged. The carbon dioxide gas replacement rate is desirably in the range of 10 to 88%.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a shellless packaged raw egg according to an embodiment of the present invention will be described in detail based on the drawings.
1 and 2 show a shellless packaged raw egg pack according to an embodiment of the present invention, FIG. 1 is a perspective view thereof, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
The shellless packaged raw egg pack 1 is composed of a unit pack 5 comprising a container body 2 and a lid 3, and in the embodiment shown in the figure, the container body 2 is constructed by connecting six unit packs 5 that can each contain one egg. Has been. Each unit pack 5 has a housing portion 6 formed of a cylindrical portion having a hemispherical lower portion and an upper portion opened, and a lid formed on the outer peripheral surface of the opening portion so that the unit pack 5 can be stored in an egg holder of a household refrigerator. The adjacent unit packs 5 are connected to each other in the vicinity of the tangential portion of the flange to form a communication portion 8 and are integrally formed through the connection portion. On the other hand, the lid material 3 is heat-sealed to the lid material seal flange 7 and the communication portion 8 in a sealing process, which will be described later, and the portion protruding outward from the lid material seal flange 7 is the same as or after the heat sealing process. It is cut and removed in the process, and as shown in the figure, the opening of the unit pack is covered and communicated via the communication portion 8. In the figure, 9 represents egg yolk and 10 represents egg white. Further, the lid material may be a molded lid.
[0018]
The container body 2 and the lid material 3 can hold the shellless raw egg sealed in the container so that the decrease in the retention of carbon dioxide gas with time is less than in the case of (1) shelled raw egg. (2) It must be transparent so that the state of the raw eggs stored inside can be observed from the outside. As satisfying the above condition (1), in the present invention, with the raw egg filled and sealed, the unit carbon dioxide permeation amount of the container is 1417 ml / m ² · in terms of a gas partial pressure difference of 1 atm between the high pressure side and the low pressure side. The container was configured to be 24 hr or less. If the unit carbon dioxide permeation amount is 1417 ml / m ² · 24 hr or more, the carbon dioxide gas barrier property is inferior to that of a raw egg shell, and the effect of suppressing the HU value over the shelled raw egg cannot be obtained. It is preferably 140 ml / m ² · 24 hr or less. Then, a transparent or translucent material having a carbon dioxide gas permeability of 8500 ml / m ² · 24 hr or less and capable of seeing through the inside was selected as a material satisfying the condition.
[0019]
As a material satisfying the above conditions, a single layer or multilayer material including PET, polyvinyl chloride, ethylene vinyl alcohol copolymer, or the like can be employed. The container body is injection-molded from these materials, and the lid is composed of a film made of these materials. However, the container body and the lid are not necessarily the same material, and may be a combination of different materials. It is desirable that the sealing surface of the material and the container body is made of an easily heat-sealable material.
[0020]
The above shellless packaging pack is sterilized shellless packaging pack, which is microbially safer than shelled raw eggs by sterilization during filling packaging and subsequent prevention of bacterial invasion. Allows long-term distribution of fresh eggs. In the manufacture of the sterilized packaging pack, first, the outer peripheral surface of the shell is washed in a shelled state and the shell is sterilized. On the other hand, the inner peripheral surface and the outer peripheral surface of the container body are sterilized in the container body cleaning and sterilization process, and the lid material is sterilized in the lid material sterilization process. Then, by dividing the cleaned and sterilized raw egg in an aseptic atmosphere, filling the container body of the cleaned and sterilized container body, and then substituting the air in the head space with sterilized carbon dioxide and heat sealing the lid material Then, the container body filled with the shellless raw egg is sealed to obtain a shellless sterilized packaged raw egg. Each of these steps is performed in a sterilization booth where ambient air is cleaned, but by devising to prevent the flow of air between the booths of each step, for example, a shell egg washing sterilization step, By preventing the air in the booth where the container body washing and sterilization process is performed from flowing into the booth where the filling process and the sealing process are performed, a shellless sterilized packaging raw egg with higher sterility Can be obtained.
[0021]
【Example】
In order to confirm the operation and effect of the present invention, a plurality of container bodies made only of unit containers for filling one egg whose bottom part is made of a dome-shaped container body were made using PET and a cover material using an aluminum foil laminate. . The dimensions of the container body and the lid are as follows.
container:
Opening port diameter 4.33cm
Bottom dome radius 2.0 cm
Height 5.5 cm
Container volume 70.3 cm ³
Surface area (overall) 87.4 cm ²
Surface area (lid) 14.7 cm ²
Surface area (torso) 72.7 cm ²
Body thickness 0.15mm
Each container was filled and sealed with eggs having an egg weight of 60 g and a volume of 52.2 cm ³ in a shellless state. The raw eggs to be filled in each container are sealed in a bag made of an aluminum foil laminated film substituted with carbon dioxide as described above so that the initial amount of carbon dioxide contained in each egg is the same for each egg. And what was preserve | saved for one week was used. The lid material was an aluminum foil laminated film. Therefore, in this case, there is no carbon dioxide permeation from the lid material, and carbon dioxide is considered to be transmitted exclusively from the container body.
[0022]
The shellless packaged raw eggs obtained as described above are stored indoors at a storage temperature of 25 ° C., immediately after packaging, after 1 day, after 3 days, after 7 days, and after 14 days, the HU value is taken out from the container. Was measured. Further, as a comparative example, except that the container body is made of PP, a container made so that each of the above dimensions is exactly the same as the above example is filled and sealed with a shellless raw egg having the same conditions as described above, Eggs were produced, and the HU value was measured every predetermined number of days in the same manner to examine the change over time of the how unit. The results are shown in FIG. 3 together with the shell eggs described above. In FIG. 3, a diagram c is an example manufactured with PET. In this case, as is clear from the figure, there is almost no change in the how unit with time, and a slight decrease is observed even after 14 days. It can be seen that the freshness is clearly superior to that of the fresh egg. On the other hand, in the case of the container formed of PP of the comparative example (line b), the change with time was small compared with the shelled egg, but the effect of suppressing the decrease in the HU value was small.
[0023]
Next, the change with time of the amount of residual carbon dioxide of these raw eggs in the container was examined. Until the carbon dioxide concentration in the container matches the carbon dioxide concentration in the atmosphere, the amount of carbon dioxide remaining gradually decreases due to the permeation of carbon dioxide from the inside of the container to the outside. Since it is affected by the difference in partial pressure of carbon dioxide gas, it is difficult to actually measure. Therefore, in the experiment, the temporal change in the amount of residual carbon dioxide gas in the container was examined by computer simulation based on the following calculation formula.
In the case of a plastic container, the sequential carbon dioxide concentration in the container can be expressed by the following equation.
CA (n + 1) = CA (n) + ΔQ / V (n) (2)
Where CA (n + 1): carbon dioxide concentration CA (n) after a certain time: carbon dioxide concentration ΔQ at a certain time ΔQ: carbon dioxide permeation amount V (n) at a certain time: head space volume at a certain time The amount of carbon dioxide gas permeation can be expressed by the following equation.
ΔQ = R × Sq × (Aco ₂ −Pco ₂ ) (3)
Here, R: Carbon dioxide permeability Sq: Container permeation area Aco ₂ : Carbon dioxide partial pressure in the atmosphere Pco ₂ : Carbon dioxide partial pressure in the container at a certain time
Accordingly, the amount of carbon dioxide in the container was obtained by calculating the concentration of carbon dioxide in the container every certain time (12 hours in this experiment) and sequentially adding the amount of carbon dioxide permeated within that time. The result is shown in FIG. As a result, in the case of the comparative example in which the material is PP, the change in the amount of residual carbon dioxide gas with respect to the number of days elapsed substantially matches as shown in the figure. In this case, the unit carbon dioxide gas permeation amount of the comparative example can be calculated by the following equation.

Therefore, considering that the comparative example is almost the same value as that of the shelled raw egg, it is understood that the unit carbon dioxide permeation amount should be less than that on the basis of this unit carbon dioxide permeation amount. . Further, in the case of the comparative example in which the container body was made of PET, the unit carbon dioxide gas permeation amount was 57 ml / m ² · 24 hr (partial pressure difference 1 atm). In this case, as shown in the figure, the decrease in the amount of residual carbon dioxide with respect to the number of days elapsed was also slight. As shown in the diagram (c) of FIG. 3, the change over time of the how unit is hardly reduced as compared with the shell eggs, and it has been confirmed that there is a special effect in maintaining freshness. In addition, in the case of an Example and a comparative example, although a how unit increases with respect to a time-dependent change, it is estimated that this is due to the following causes. In the case of a raw egg, there is moisture permeation from the shell, so there is a change in weight, and the measurement is based on the weight each time. However, in the case of the example and the comparative example, there is no change in weight because there is no permeation of moisture, so it is assumed that the error occurred due to the calculation based on the initial weight of the shelled raw egg.
[0025]
While the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described examples, and various design changes can be made within the scope of the technical idea. For example, in the above embodiment, the container body is filled with only one raw egg, but the number of fillings in each container is arbitrary, and the size of the container can be selected accordingly. it can. In addition, as long as the unit carbon dioxide gas permeation amount satisfies the above conditions, the material and thickness thereof are not particularly limited.
[0026]
【The invention's effect】
As described above, according to the present invention, the freshness of raw eggs is increased for a long time by filling and sealing raw eggs in a transparent or translucent container having a unit carbon dioxide permeability less than that of egg shells in a shellless state. The product value can be increased over time, and the white and yellowish state of the raw egg can be directly discriminated from the outside, so that the consumer can purchase it with peace of mind by checking its freshness. In addition, the packaging can maintain a pH value in a neutral region where lysozyme, which is contained in a large amount in egg whites, exhibits the strongest antibacterial activity, and can suppress a decrease in the antibacterial activity of lysozyme. . Furthermore, by sterilizing and packaging, there is no risk of being contaminated with bacteria compared to raw eggs with shells, and it is safe. Furthermore, since it is a container package, handling at the distribution stage is also easy. Further, since there is no shell, there is no need to break the shell during cooking, the contents can be easily taken out, and the shell waste is not generated each time.
[Brief description of the drawings]
FIG. 1 is a perspective view of a shellless packaged raw egg according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA.
FIG. 3 is a diagram showing changes in howe units with respect to days of aging in raw eggs with shells and raw eggs without shells.
FIG. 4 is a diagram showing changes in the amount of residual carbon dioxide gas with respect to the number of elapsed days in shelled raw eggs and shellless raw eggs.
FIG. 5 is a hydrogen ion-carbon dioxide gas quantity diagram for estimating an initial value of carbon dioxide from a pH value.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Aseptic packaging raw egg pack 2 Container body 3 Lid material 5 Unit pack 6 Storage part 7 Lid material seal flange 8 Communication part 9 Yolk 10 White

Claims (2)

It consists of a shelled egg cleaning and sterilization process that cleans and sterilizes the outer peripheral surface of the shell in a shelled state, a housing part that stores the raw egg in a shellless state, and a lid seal part. Cleaning the container body that cleans and sterilizes the inner and outer peripheral surfaces of the container body formed so that the unit carbon dioxide gas permeation amount is 1417 ml / m ² · 24 hr or less in terms of the gas partial pressure difference between the high pressure side and the low pressure side Raw egg shell sterilization and filling process, shelled raw eggs that have been washed in shelled state and shells are sterilized and divided into aseptic atmosphere and filled into the container of the container body that has been cleaned and sterilized It consists of a sealing process that seals and seals the container of the egg-filled container body with a lid. It keeps the freshness of the egg white of the shellless raw egg fresh and can be observed from the outside, and the antibacterial activity of lysozyme Wrapped so as to suppress a decrease in activity effect Sterilization packaging method Mukara packaging raw eggs characterized and. The raw egg sterilization filling process is carried out with carbon dioxide gas sterile atmosphere, sterilization and packaging method of shell-less packaging raw egg according to claim 1, wherein the packaging by replacing the air in the container body into carbon dioxide.

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