Premessa: la ricerca ha evidenziato l’importanza della pasta madre realizzata con LAB selezionati e con quelli autoctoni delle farine di farro dicocco e spelta per sfruttare completamente il potenziale di questi “grani antichi”. L’optimum sarà, quindi, partire da una pasta madre con una selezione di lattobacilli (LAB) e rinfrescarla con le farine in oggetto apportando, così, il contributo del Lab presenti nelle stesse farine.
“Lactobacillus brevis 20S, Weissella confusa 24S and Lact. plantarum 31S were used as pool 1 to start spelt flour. Lactobacillus plantarum 6E, Lact. plantarum 10E and W. confusa 12E were used as pool 2 to start emmer flour. ‘Ancient grains’ could serve as an abundant source of protein and soluble fibre, oleic acid and macro- and micro-elements (Bonafaccia et al. 2000; Ruibal-Mendieta et al. 2005). In spite of this increasing interest, few results are available on the microbiota of spelt and emmer and on their suitability for bread making. Selection of starters within endogenous strains was considered the most important pre-requisite. Some recent studies (Di Cagno et al. 2008a,b,c) on fermented vegetable foods, which also included strains of Lact. plantarum, have clearly shown that endogenous strains are preferred to those of the same species isolated from different matrices to promote a rapid and intense process of acidification with a positive influence on nutritional and technological properties. To use, mixed starters was considered functional to completely exploit the potential of spelt and emmer flours. Mixture of strains with dif- ferent carbohydrate metabolism is frequently used because it may guarantee optimal acidification and sensory properties (Gobbetti 1998). Mixed obligate and facultative heterofermentative lactic acid bacteria starters, as selected in pool 1 and 2, ensured rapid growth and acidification, the capacity to liberate FAA and exploited the rheology, sensory and nutritional properties of the raw flours. This was according to a two-step fermentation process. The use of sourdough comprising selected and autochthonous strains of lactic acid bacteria was considered the most suitable biotechnology to exploit the potential of spelt and emmer flour in bread making. Fermentation of spelt, emmer or wheat flours by pool 1 and 2 was allowed according to a two-step fermentation process (Fig. 1). As the general rule, it was possible to keep it lower than 4Æ0 in spelt and emmer sourdoughs, which implied a considerable synthesis of acetic acid (Gobbetti et al. 2005). Acidity of spelt and emmer breads was perceived through sensory analysis and positively influenced the volume and crumb grain of breads. Flavour of bread is known to be influenced by the combination of raw materials, fermentation and baking process (Gobbetti et al. 2005). Spelt and emmer sourdough breads received the highest score for acid taste, and a clear preference for the global taste was assigned to spelt sourdough bread. First, this study showed the suitability of spelt and emmer flours to be used for bread making according to a two-step fermentation process. Sourdough biotechnology based on selected starters was indispensable to completely exploit the potential of these ‘ancient grains’. Spelt and emmer flours were purchased from a local market. The characteristics of emmer flour were water content, 15,0%; protein (N · 5,70), 15,1% of dry matter (d.m.); fat, 2,5% of d.m.; ash, 1,9% of d.m.; and total soluble carbohydrates, 2,6% of d.m. The characteristics of spelt flour were water content, 15,0%; protein (N · 5,70), 19,1% of d.m.; fat, 2,2% of d.m.; ash, 2,0% of d.m.; and total soluble carbohydrates, 2,7% of d.m. Spelt and emmer flours: characterization of the lactic acid bacteria microbiota and selection of mixed starters for bread making. (
R. Coda, L. Nionelli, C.G. Rizzello, M. De Angelis, P. Tossut and M. Gobbetti. 1 Department of Plant Protection and Applied Microbiology, University of Bari, Bari, Italy 2 Puratos N. V., Industrialaan, 25 B-1702z, Groot-Bijgaarden, Belgium. 2009).”
