The fate of thiamin and riboflavin during the preparation of couscous

Couscous is an agglomerated and steamed product usually made from durum semolina. The processing of couscous consists of traditional or commercial manufacture followed by preparation in the home prior to consumption. The proximate and particle size analysis of five traditional and four commercial samples is given. Characteristically, the commercial samples were less homogeneous than the traditional ones. The initial thiamin content for both sets of samples was similar (0.26 ± 0.07 mg/100 g and 0.22 ± 0.02 mg/100 g). The riboflavin content of the traditional sun-dried samples tended to be lower than that of the commercial samples (0.037 ± 0.006 g/100 g and 0.066 ± 0.01 μg/100 g). e losses during steaming amounted to 15.4 ± 2.7% for thiamin and 36.1 ± 5.7% for riboflavin. It is suggested that eye problems common in supra-Saharan Africa are caused by the sun-drying of couscous which is the cereal staple.