Investigation of the suitability of Western and Southern Cape wheat flour for production of traditional South African steamed bread
Due to a lack of electrical ovens, it is often found that in the households of the lower-income communities, a home-made steamed bread is prepared in a saucepan on a gas cooker or an open fire. The requirements of flour used to produce high-quality steamed bread are poorly defined. The suitability of Western and Southern Cape wheat for steamed bread production was, therefore, investigated. A marked increase in the nutritive value of steamed bread was reported compared to that of conventionally baked bread, mainly due to the loss of available lysine during conventional baking. Samples of three spring wheat cultivars that were produced during the 1995 and 1996 seasons in the Western and Southern Cape were selected. Flour protein content of these samples varied between 8 and 16%. Flour protein content, Falling Number determinations, gluten content, Mixograph, Alveograph and Rheofermentometer measurements and the 10 g baking test were performed on each of the flours. Steamed and conventionally baked breads were prepared for each cultivar at the four selected flour protein levels, respectively. Total bread volume, weight, height and texture, crust and crumb colour and lysine availability were measured for each loaf of bread. None of the Rheofermentometer measurements correlated significantly with flour protein content or any of the analytical and rheological measurements performed on the flour. All the crust colour parameters of conventionally baked bread correlated significantly with flour protein content. Even though significant correlation was observed for three crust colour parameters of steamed bread, the correlation was lower compared to that of conventionally baked bread. At the four different protein levels, more variation was observed in the elasticity of conventionally baked bread compared to the steamed bread, the texture of the steamed bread was finer and firmer and the crumb was more sticky. The browning reaction occurring in conventionally baked bread results in less available lysine than would be the case for steamed bread. In this study, higher availability of lysine was only the case when steamed bread was produced from high protein flour. Western and Southern Cape spring wheat, irrespective of protein content are, therefore, suitable for the production of good quality steamed bread.