Thiamin fortification of bread-making flour: Retention in bread and levels in Australian commercial fortified bread varieties

In Australia, thiamin is mandatorily added to bread-making flour with the main purpose of fortification and reducing the prevalence of Wernicke–Korsakoff syndrome. This study aims to measure the retention of added thiamin through laboratory-scale bread processing and provide an update on thiamin contents in commercially fortified bread and flatbread varieties since the introduction of the program in 1991. Even though baking caused degradation loss of thiamin (approximately 16%), the laboratory fortified white bread had a 25% higher thiamin content than its corresponding flour, and laboratory fortified wholemeal bread showed a 16% increase (p < 0.05). Thiamin levels in commercially fortified bread and flat bread varieties ranged between 0.24 and 1.9 mg/100 g (dry weight basis). It can be suggested that most of the bread varieties were made from flour fortified at the minimum mandated level (0.64 mg/100 g flour). Samples of flat bread varieties (white without yeast, wholemeal with yeast and wholemeal without yeast) showed low thiamin levels (0.24–0.49 mg/100 g, dry weight basis). The results suggest that the flat bread varieties were likely made from either commercially under-fortified flour or unfortified general-purpose flour, as only bread-making flour is fortified with thiamin.