Closing unit associable with a keg type container suitable to contain a beverage, and consisting of two cooperating coaxial containers (11, 12), wherein one external container has anchoring means, or a threaded portion, said closing unit being suitable to cooperate, also stably, with a beverage dispensing unit, wherein the components of the closing unit are made of recyclable plastic material, possibly also in direct union with the containers (11, 12), said closing unit having in reciprocal cooperation: - a valve assembly; - and a closing device, able to be stably anchored to said threaded portion and reciprocally positioning with respect to each other said valve assembly and said two containers, internal and external; wherein said valve assembly comprises: - a mobile sealing unit comprising a female sealing component cooperating with a male sealing component; - a valve body (41; 141) provided with a component (38; 39) of the mobile sealing unit; - a spring device provided with the other component (39; 38) of the mobile sealing unit, wherein said valve body (41; 141) comprises an upper annular portion, an intermediate wall equipped, during use, with a passage aperture, and connected to the upper annular portion by at least one connection element, and a lower extension defining a housing cavity for said spring device, wherein said at least one connection element comprises at least one passage slit or passage channel for a gas, at least one of the following gaskets being present in said valve assembly: a lateral gasket associated with the valve body (41; 141), suitable to act as a seal between the valve body (41, 141) and the internal container and configured to cooperate with a surface of a containing compartment of said internal container, an internal gasket associable, during use, with an internal surface of said internal container and suitable to act as a seal for the mobile sealing unit, an upper gasket, associated with the upper annular portion and associable, during use, with the upper part of said two containers (11, 12). - a valve assembly; - and a closing device, able to be stably anchored to said threaded portion and reciprocally positioning with respect to each other said valve assembly and said two containers, internal and external; wherein said valve assembly comprises: - a mobile sealing unit comprising a female sealing component cooperating with a male sealing component; - a valve body (41; 141) provided with a component (38; 39) of the mobile sealing unit; - a spring device provided with the other component (39; 38) of the mobile sealing unit, - a mobile sealing unit comprising a female sealing component cooperating with a male sealing component; - a valve body (41; 141) provided with a component (38; 39) of the mobile sealing unit; - a spring device provided with the other component (39; 38) of the mobile sealing unit, wherein said valve body (41; 141) comprises an upper annular portion, an intermediate wall equipped, during use, with a passage aperture, and connected to the upper annular portion by at least one connection element, and a lower extension defining a housing cavity for said spring device, wherein said at least one connection element comprises at least one passage slit or passage channel for a gas, at least one of the following gaskets being present in said valve assembly: a lateral gasket associated with the valve body (41; 141), suitable to act as a seal between the valve body (41, 141) and the internal container and configured to cooperate with a surface of a containing compartment of said internal container, an internal gasket associable, during use, with an internal surface of said internal container and suitable to act as a seal for the mobile sealing unit, an upper gasket, associated with the upper annular portion and associable, during use, with the upper part of said two containers (11, 12).