The use of sorghum to produce gluten-free breads (GFB): a systematic review

Abstract

Sorghum is a strategic gluten-free crop cereal for food security due to its tolerance to drought and heat environment, with an interesting composition related to its similarity to corn, aggregated to resistant starch and phenolic compounds in many of the accessions. Sorghum grains should be applied for human consumption in several gluten-free products, such as breads. We assessed application of sorghum to make gluten-free breads (GFB) and to evaluate the advantages already achieved in its use, and what challenges remain. We searched electronic databases and bibliographies published from January 2005 to June 2015 by using the keywords sorghum, bread and gluten-free, and eleven studies on sorghum GFB were included. Sorghum GFB were developed mainly with red and white commercial sorghum flours and little information was provided about accessions. Only one of the studies has explored nutritional advantages of sorghum flour on glycemic index of bread. The other studies have focused on technological approaches to improve bread quality, which involved germination of sorghum grains, high pressure, application of sourdough and the use of starches and additives. Positive results were achieved with the partial application of germinated sorghum flour, sourdough, and lyophilized pressure-treated sorghum batter. Good results with the partial replacement of sorghum flour by starch, mainly native cassava starch, was observed. Concerning additives, emulsifiers were the most successful, but levels optimization were still required. The limited number of sorghum accessions used in the studies in comparison with the high diversity of sorghum and the scarce information on the accessions indicates that the potential of sorghum was not fully investigated for technological application. The use of accessions with quantified tannins and other phenolic compounds and resistant starch should be studied for health benefits, and the technological impacts related to the presence of these compounds must be investigated and overcome. Optimization of additive levels and association of positive results from different studies may contribute to quality improvement. Sensory evaluation and consumer studies are still incipient and very important, especially in countries in which sorghum is not used for human consumption.