Agents such as citric acid, fumaric acid, adipic acid, tartaric acid, and/or malic acid may be used to provide tartness.Additional ingredients in the form of analgesics (e.g. aspirin), mild stimulants (e.g. caffeine), or relaxants, may be added in specialized product applications.To provide stability, the carbonated protein drink typically includes an antifoaming agent such as dimethylpolysiloxane