Biochemical and technological characterization of C4 Cycle Gluten Free Cereals: ERAGOSTIS TEF and SORGHUM BICOLOR

The objective of this study was to evaluate five sorghum genotypes, one for zootechnical use and four food-grade hybrids, and two commercial teff genotypes (brown and white grain), for their technological, biochemical and nutritional traits, comparing them with a durum wheat cultivar as control, in order to identify the most suitable for the formulation of innovative wholegrain, gluten free products of high qualitative value to develop a sustainable agri-food chain. The data concerning kernel and flours properties of the sorghum food-grade, on average, reported lower values than durum wheat control for kernel weight (-56%), test weight (-14%), sedimentation test (-56%), falling number (-16%) and yellow index (-19%), whereas brown index was higher (+38%) and kernel hardness (+0.5%) comparable to control. Furthermore, teff genotypes showed lower values than durum wheat control for kernel weight (-99%), sedimentation test (-50%), falling number (-18%), yellow index (-11%), whereas brown index was higher (+90%) and test weight (+2%) was comparable to control. The results showed that, on average, sorghum food-grade hybrids had higher contents of resistant starch (RS) and RS/TS (Total Starch) ratio (about 6 times higher), yellow pigments, free polyphenol and anthocyanin contents (+600%, +400% and +100% than the control, respectively). Teff genotypes, on average, were comparable to durum wheat for resistant starch content, RS/TS ratio, yellow pigments and anthocyanin contents, whereas total starch and folate contents were higher (+6 % and +40%) than in wheat. Furthermore, the beverage transformations of these two gluten free cereals revealed malts with low amylase activity, typical of low-alcohol drinks, and useful for light and gluten-free beer market. Otherwise, the malts produced could be used in combination with other malts for the production of innovative fermented beverages, not yet available on the market. Finally, the teff-based "Tigelle", typical Italian unleavened focaccias from Emilia Romagna, presented good overall acceptance scores from the hedonic analysis carried out by not-expert people, with higher scores for crumb and crust color in white teff bread, whereas the sample with malt was preferred for its aroma and taste. In conclusion, the data of this study showed that the four food-grade sorghum hybrids and the two teff genotypes examined have technological and nutritional characteristics comparable with the durum wheat, used as control, for the most of the parameters examined. When the analyzed lines showed lower values than wheat, they are still acceptable for the transformation processes. The data obtained in this study, highlighted as sorghum and teff can constitute promising alternative ingredients in the gluten free market. Furthermore, given their resilience to both drought and heat stress, teff and sorghum could be one of the answer to global sustainability on food and nutrition security.