The present disclosure pertains to a laminate membrane for sealing an inner compartment in a packaging container comprising a top member and a bottom member. The top and bottom members are laminated sheet materials. The top member has a thickness, a top member first surface and a top member second surface facing the bottom member. The bottom member has a bottom member first surface facing the top member second surface and a bottom member second surface. The laminate membrane is provided with a valve for allowing gas in the inner compartment of the packaging container to exit therefrom. The valve has a valve outer edge and is arranged on the bottom member first surface. The valve is arranged within an opening in the top member such that an opening edge encircles the valve. A surface area of the opening is greater than a surface area of the valve.