Soft faecal pellets of partially digested food are excreted and generally consumed immediately. Dietary fibers are plant carbohydrates which cannot be digested by mammalian enzymes. This blood contains nutrients and toxins extracted from digested contents. Carbohydrates are usually taken into cells once they have been digested into monosaccharides. The potato is rarely eaten raw because raw potato starch is poorly digested by humans. However fats are mainly digested in the small intestine. When the chyme is fully digested, it is absorbed into the blood. The ingested material is then digested in the phagosome. Xylose is a sugar that does not require enzymes to be digested. Like sucrose, isomaltulose can be digested to glucose and fructose. In bacteria and some animals, sucrose is digested by the enzyme invertase. These nutrients help feed the juveniles after the yolk sac has been digested. Without sufficient enzymatic function, these GAGs cannot be digested properly. The settled solids are anaerobically digested, reducing the volume of solids. The free signal peptides are then digested by specific proteases.