The major salivary glands are the largest and most important salivary glands. They produce most of the saliva in your mouth. There are three pairs of major salivary glands: the parotid glands, the submandibular glands, and the sublingual glands. parotid glands produce a serous, watery secretion. submaxillary (mandibular) glands produce a mixed serous and mucous secretion. sublingual glands secrete a saliva that is predominantly mucous in character.