Digestive Juices Digestive Juices and Their Functions Salivary Glands Bicarbonate fluid Lubricates food during chewing. Salivary Lipase Prepares fat for digestion. Gastric Secretions Acid Initiates digestion of protein and kills bacteria. Pepsin Aids in initiation of protein digestion. Gastric Lipase Initiates digestion of dietary fat. Mucous Lubricates and protects lining of stomach. Intrinsic Factor Aids in absorption of Vitamin B12 by small intestine. Liver Secretions Bile Acids Detergent that helps dissolve dietary fat. Phospholipids Promotes absorption of fats. Cholesterol Excreted in bile. Immunoglobulins Protect from bacteria and other harmful organisms. Mucus Protects from bacteria.