The seed endosperms of Afzelia africana and Detarium microcarpum are known materials for soup thickening in Southeast and some other parts of Nigeria. The hydrocolloids responsible for the thickening effect were isolated from the seed endosperms and characterised using GC-MC technique. The volatile fraction of A. africana seed hydrocolloids showed the presence of seventeen constituents consisting of aromatic (0.80%), hydrocarbons (7.67%), phenolic (0.39%), esters (10.19%), fatty acids (36.35%), alcohols (42.24%) and steroid (2.36%). On the other hand, twenty two compounds were identified in the seed hydrocolloids of D. microcarpum. They consist of hydrocarbons (20.32 %), aromatics (2.14 %), aldehyde (0.49%), phenolic (0.37%), fatty acids (67.80%), esters (5.09 %) and alcohol (3.80%). This investigation reveals that the two hydrocolloids contain appreciable amount of volatile phytochemicals that could provide certain physiological benefits to the body. Hydrocolloids from D. microcarpum contain more volatile phytochemicals than that of A. africana.