Involved in the digestion of starch (Probable). Endohydrolysis of (1->4)-alpha-D-glucosidic linkages in polysaccharides containing three or more (1->4)-alpha-linked D-glucose units. Binds 1 Ca(2+) ion per subunit. Binds 1 Cl(-) ion per subunit. Monomer. Highly expressed in L2 larvae and adult insect stages, which are the main feeding phases. Low levels are detected in eggs and first instar (L1) stage, whereas a 200-fold increase is observed at the second instar (L2) stage. Expression is significantly reduced during the pupal stage, a period in which the insects do not feed. After ecdysis, the expression increases again 200-fold during the adult stage along with the resumed feeding. A possible target of coffee bean insect pest control. This important digestive enzyme could be for example knocked down using the RNAi method. Belongs to the glycosyl hydrolase 13 family.