Delivery assembly for a coffee beverage extracted under pressure by means of water through a substrate of powdered coffee, said assembly comprising: - an extractor body which has a passage circuit from an entry aperture for the water to a delivery aperture of the coffee beverage, there being present, along said passage circuit, a first seating in which a selectively removable filter is provided which defines an extraction chamber to receive said substrate of powdered coffee made downstream of said entry aperture and, downstream of said first seating, a second seating communicating with said delivery aperture, the delivery assembly being characterized by - a proportional membrane valve selectively adjustable to control the delivery flow of said coffee beverage at exit from said extraction chamber and able to be housed in said second seating, said valve comprising: - a valve body in which a segment of the passage circuit is present, in communication on one side with said extraction chamber defined in said filter and on the other side with said delivery aperture; - a shutter assembly on which a mobile membrane is mounted and provided with an actuation element associated with said membrane; said valve body being releasably coupled with said shutter assembly, so as to selectively present a first mounted condition, defining an interception chamber present between said valve body and said shutter assembly in which said membrane is mobile to selectively intercept said segment of the passage circuit of the valve body, maintaining said segment separate from the actuation element of the shutter assembly, in said first mounted condition said valve being positioned in said second seating in order to control the flow of extracted coffee beverage delivered through said extraction chamber and a second disassembled condition, in which said shutter assembly is disassembled from said valve body for the purposes of cleaning said valve. - an extractor body which has a passage circuit from an entry aperture for the water to a delivery aperture of the coffee beverage, there being present, along said passage circuit, a first seating in which a selectively removable filter is provided which defines an extraction chamber to receive said substrate of powdered coffee made downstream of said entry aperture and, downstream of said first seating, a second seating communicating with said delivery aperture, the delivery assembly being characterized by - a proportional membrane valve selectively adjustable to control the delivery flow of said coffee beverage at exit from said extraction chamber and able to be housed in said second seating, said valve comprising: - a valve body in which a segment of the passage circuit is present, in communication on one side with said extraction chamber defined in said filter and on the other side with said delivery aperture; - a shutter assembly on which a mobile membrane is mounted and provided with an actuation element associated with said membrane; said valve body being releasably coupled with said shutter assembly, so as to selectively present a first mounted condition, defining an interception chamber present between said valve body and said shutter assembly in which said membrane is mobile to selectively intercept said segment of the passage circuit of the valve body, maintaining said segment separate from the actuation element of the shutter assembly, in said first mounted condition said valve being positioned in said second seating in order to control the flow of extracted coffee beverage delivered through said extraction chamber and a second disassembled condition, in which said shutter assembly is disassembled from said valve body for the purposes of cleaning said valve. - a valve body in which a segment of the passage circuit is present, in communication on one side with said extraction chamber defined in said filter and on the other side with said delivery aperture; - a shutter assembly on which a mobile membrane is mounted and provided with an actuation element associated with said membrane;