Effects of processing with dry heat and wet heat on the antioxidant profile of sorghum.

The effects of domestic processing with dry heat (F2-oven/milling; F3-milling/oven; F4-microwave oven/milling; F5-milling/microwave oven; F6-popped grains/milling) and wet heat (F7-cooking in water/drying/milling) on the antioxidant profile of sorghum flours (F1-raw flour) were evaluated. 3-Deoxyanthocyanidins and total phenolic compounds were stable to dry heat (retention between 96.1% and 106.3%) and reduced with wet heat. All processing with dry heat increased the vitamin E content (2,201.9-3,112.1 µg/100 g) and its retention, and reduced the carotenoids (4.78-17.27 µg/100 g). The antioxidant activity in processed flours with dry heat remained constant (F3 and F6) or increased (F2, F4 and F5) and decreased after processing with wet heat. Overall, the grains milled before processing in oven and in microwave oven retained more vitamin E and less carotenoids than those milled after these processing. In conclusion, dry heat did not affect the phenolic compounds and 3-deoxyanthocyanidins of sorghum, but increased the vitamin E and antioxidant activity, and reduced the carotenoids. The wet heat processing reduced all antioxidant compounds except carotenoids, which increased.

Folates retention in brassica vegetables consumed in Brazil after different cooking methods.

The present study aimed to determine the effects of different traditional cooking methods on folate (tetrahydrofolate - THF, 5-methyltetrahydrofolate - 5- MTHF and 5-formyltetrahydrofolate - 5-FTHF) retention in leafy vegetables. The analysis of folates was carried out by high performance liquid chromatography (HPLC), with detection by fluorescence, using gradient elution, mobile phase of acetonitrile and phosphate buf- fer solution. The retention of isomers in vegetables after cooking ranged from 17.0 % to 87.2 % for THF, 53.4 - 94.1% for 5-MTHF and 39.0 - 107.9% for 5-FTHF. The retention of folates depended on the food matrix, the kind of isomer, and the cooking methods used. It is recommended that one should have more control over the choices for methods and time of cooking and the amount of water used at home and at foodservice as well.