Application of low doses of ionizing radiation in the Brazilian fruit tucuma (Astrocaryum vulgare Mart.)

The tucuma (Astrocaryum vulgare Mart.) is a native fruit of Amazonia, occurring mainly in the state of Para, but also found in the Brazilian northeast states and in the Brazilian central-western states. The tucuma is considered an excellent source of carotenoids with a very high concentration of β-carotene, which is a precursor of vitamin A. In addition to carotenoids it is an important source of vitamin B2 (riboflavin) in fruits. This study aimed to analyze the effects of gamma radiation on the nutritional value of tucuma. The fruits were irradiated at doses of 0.5, 1.0 and 2.0 kGy irradiator with a source of cesium 137. The carotenoids were determined by spectrophotometry. The analysis of α and β-carotene, thiamine, riboflavin were carried out by high performance liquid chromatography (HPLC). The β-carotene accounts for 80% of total carotenoids in tucuma, and with a dose of 2 kGy, it showed the highest reduction of β-carotene, about 7.5% in relation to the control. The tucuma fruit showed high levels of riboflavin from 0.183 to 0.222 μg 100 g-1, and maintained stability after the gamma radiation process. However, it had low levels of thiamine from 0.050 to 0.033 μg 100 g-1, and irradiated at a dose of 2 kGy showed significant reductions of thiamine, about 34% in relation to the control. (author)