Assessment of iron bioavailability from different bread making processes using an in vitro intestinal cell model

Area of Science:

• Food Science and Technology
• Human Nutrition
• Biochemistry

Background:

• Myo-inositol hexakisphosphate (IP6), also known as phytic acid, is a primary iron chelator found in cereals and bread.
• Phytic acid can inhibit iron absorption, impacting nutritional value, especially in iron-fortified products.

Purpose of the Study:

• To evaluate the impact of sourdough, conventional yeast, and Chorleywood Bread Making Process (CBP) baking on IP6 content in wholemeal bread.
• To assess the effect of these baking processes on iron uptake and bioavailability in Caco-2 cells.
• To determine the potential of sourdough bread in improving iron nutrition.

Main Methods:

• Analysis of IP6 content in wholemeal flour and bread produced via three different commercial baking processes.
• In vitro simulated digestion of bread samples to measure iron release.
• Assessment of iron uptake and ferritin production in Caco-2 cells following simulated digestion and iron addition.

Main Results:

• Sourdough process completely degraded IP6; CBP and conventional yeast reduced IP6 by 75% compared to wholemeal flour.
• Iron release after simulated digestion was 8-fold higher in sourdough bread compared to other bread types.
• Sourdough bread significantly increased ferritin response (4.8-fold) in Caco-2 cells when iron was added, unlike other breads.

Conclusions:

• The sourdough baking process effectively eliminates IP6, leading to higher iron release.
• While cellular iron uptake showed no difference, sourdough bread demonstrated superior potential to enhance iron bioavailability.
• Sourdough bread consumption may contribute positively to iron nutrition due to its processing advantages.