Human digestive system secreted by innumerable gastric glands in the stomach, to provide a slimy protective layer against the damaging effects of the chemicals on the inner layers of the stomach. At the same time that protein is being digested, mechanical churning occurs through the action of peristalsis, waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. Gastric lipase secreted by the chief cells in the fundic glands in the gastric mucosa of the stomach, is an acidic lipase, in contrast with the alkaline pancreatic lipase. This breaks down
Digestive biscuit packs sold annually. Digestives are also popular in food preparation for making into bases for cheesecakes and similar desserts. Chocolate digestive biscuits are also available, coated on the underside with milk, dark or white chocolate. Originally produced by McVitie's in 1925 in the UK as the Chocolate Homewheat Digestive, other varieties include the basic biscuit with chocolate shavings throughout (chocolate "chips" in the biscuit mix), or a layer of caramel, mint chocolate, orange-flavoured chocolate, or plain chocolate. American travel writer Bill Bryson described the chocolate digestive as "a British masterpiece". The McVitie's chocolate digestive is the most popular biscuit in