Abstract: A piston pump for mixing air into a liquid confectionary mixture uses resilient, duck-bill shaped valves in special valve bodies to provide efficient operation, easy assembly and disassembly, and easy cleaning. In one embodiment, a duck-bill valve in a central outlet passageway of a valve body functions as an outlet check valve and has an integral resilient disk portion that fits over a face of the valve body to function as a check valve for a plurality of spaced inlet passageways. In another embodiment, a duck-bill valve within an end of a cylinder of a pump is placed over a central inlet passageway, and a spool with circumferentially spaced holes is positioned about the duck-bill valve to aid in mixing confectionary mixture and air. A separate duck-bill valve as a check valve is positioned in an outlet passageway. By using only duck-bill valves in this embodiment, fruit pulp and seeds in confectionary mixtures can be readily pumped and mixed simultaneously without plugging the valves.