Thiamin content and activity of antithiamin factor in vegetables of southern Thailand

Fourteen types of vegetable commonly consumed by people in southern Thailand were analyzed for content of endogenous free-form thiamin and activity of antithiamin factor (ATF). The mean of endogenous free-form thiamin content (μg/g vegetable) ranged from 0 in phak kuad (Diplazium esculentum (Retz.) SW.) and khanun (Artocarpus heterophyllus Lamk.) to 2.8 in sato (Parkia speciosa Hassk.). Activity of heat-stable ATF incubated for 3 h (percent thiamin destroyed/g vegetable) ranged from 2.3 in sato to 100 in phak kuad and khanun. Among the analyzed samples, activity of heat-stable ATF above 50% was found in 10 types. Activity of heat-labile ATF above 40% was found only in four types and the rest were below 15.7%. Furthermore, samples with a high activity of ATF tended to have low thiamin content.