Difference in the Chemical Changes Between the Food Products.

Plain flour goes through more gelatinization and gluten development as compared to wholemeal flour due to the presence of fiber in the wholemeal flour.

*Gelatinization = swelling of starch granules and migration of some amylose into the cooking water when starch is heated in water to thicken various food products.

*Gluten development = Complex of gliadin and glutenin that develops in wheat flour mixtures when water is added and the batter is manipulated by stirring, beating or kneading.

Wholemeal flour contains the bran of the grain as said earlier under the nutritional comparison. The fiber present in the flour absorbs water. Therefore when the flour is mixed with the liquid ingredients which contain water such as the egg and milk, the fiber absorbs the water leaving less water available in the surrounding of the flour for gelatinization to occur. This causes the plain bun using the wholemeal flour to have a weaker structure. Gelatinization occured when the batter was baked in the oven.

Also, the plain bun using the wholemeal flour does not have the 'fuller' shape and has a weaker structure is due to the reduction in gluten development. Because water is also required for this chemical process to occur. Therefore with the fiber from the bran absorbing the surrounding water, there would be less water for the starch to form gluten. The gluten is formed when the mixture was mixed to the dropping consistency.

taken from : Foods Experimental Perspectives sixth edition by Margaret McWilliams