The Importance of Lactic Acid Bacteria for Phytate Degradation during Cereal Dough Fermentation

Distaam, Università degli Studi del Molise, Via De Sanctis, 86100 Campobasso, Italy.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 05/2007; 55(8):2993-7. DOI: 10.1021/jf063507n
Source: PubMed


Lactic acid fermentation of cereal flours resulted in a 100 (rye), 95-100 (wheat), and 39-47% (oat) reduction in phytate content within 24 h. The extent of phytate degradation was shown to be independent from the lactic acid bacteria strain used for fermentation. However, phytate degradation during cereal dough fermentation was positively correlated with endogenous plant phytase activity (rye, 6750 mU g(-1); wheat, 2930 mU g(-1); and oat, 23 mU g(-1)), and heat inactivation of the endogenous cereal phytases prior to lactic acid fermentation resulted in a complete loss of phytate degradation. Phytate degradation was restored after addition of a purified phytase to the liquid dough. Incubation of the cereal flours in buffered solutions resulted in a pH-dependent phytate degradation. The optimum of phytate degradation was shown to be around pH 5.5. Studies on phytase production of 50 lactic acid bacteria strains, previously isolated from sourdoughs, did not result in a significant production of intra- as well as extracellular phytase activity. Therefore, lactic acid bacteria do not participate directly in phytate degradation but provide favorable conditions for the endogenous cereal phytase activity by lowering the pH value.

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    • "The possibility of introducing sourdough bread to the gluten-free (GF) diet would increase its nutritional value significantly, because of the unique, healthy properties of it (PoutANEN et al., 2009). Fermentation with lactic acid bacteria (LAB) strongly elevates bioavailability of micro and macroelements due to phytate degradation (rEAlE et al., 2007). Besides, the nutritive value of sourdough bread is elevated as the result of increase in B-group vitamin content as well as exogenic amino acids (PoutANEN et al., 2009). "
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    ABSTRACT: Implementation of sourdough technology would increase nutritional value and attractiveness of gluten-free bread. However, fermentation process requires stimulation. The course of fermentation of gluten-free sourdoughs prepared from maize and soy flours and maize and potato starches, enriched in glucose and casein hydrolysate or soy sprouted seeds used as fermentation enhancers was evaluated. The clearest effect of the supplementation was observed in the case of sourdough prepared from starches only. The addition of glucose in the amounts as low as 0.5% has proved to be enough to enhance fermentation effectively. Supplementation of the sourdoughs with peptides was not very effective; however, when used together with glucose, a synergistic effect could be detected. The addition of sprouted seeds allowed to shorten the fermentation process with up to several hours. These studies have demonstrated possibility to simplify and shorten the process of gluten-free sourdough fermentation by modification of mixtures composition.
    Full-text · Article · Jun 2014 · Acta Alimentaria
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    • "Phytate degradations during fermentation range between 0 and 90% (Kruger, Taylor, & Oelofse, 2012; Reale et al., 2007; Reddy & Pierson, 1994; Towo, Matuschek, & Svanberg, 2006). This seems to be mainly related to the endogenous phytase activity of the plant matrix (Reale et al., 2007), since this correlation is not valid when grains or legumes are first heated before fermentation . It is known that the endogenous phytases are not stable at temperatures of 55 C or higher (Wodzinski & Ullah, 1996) and thus are deactivated during heating, resulting in a limited phytate degradation. "
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    • "Many factors are known to play a role in the rate and the extent to which IP6 is degraded, among which the endogenous phytase activities of the raw materials and the processing conditions like pH, which is known to modulate the activities of both plant and microbial phytases (Greiner & Konietzny, 2006). The higher endogenous phytase activity of flour blends containing barley and wheat is consistent with the results of previous studies showing higher activities for these cereals (Egli, Davidsson, Juillerat , Barclay, & Hurrell, 2002; Reale et al., 2007) and IP6 degradation under the range of optimal pH values observed for barley and wheat phytases (Greiner & Konietzny, 2006). Moreover, the addition of malt in BW-and WrS-injeras possibly helps create a favourable environment for yeasts with phytase activities, indeed some strains of yeast species like Saccharomyces cerevisiae are known to display phytase activity (Vats & Banerjee, 2004). "
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    ABSTRACT: The influence of cereal blends, teff-white sorghum (TwS), barley-wheat (BW) and wheat-red sorghum (WrS), on fermentation kinetics during traditional fermentation of dough to prepare injera, an Ethiopian traditional fermented pancake, was investigated in samples collected in households. Barley malt was used with BW and WrS flours. WrS- and BW-injera sourdough fermentations were characterised by a transient accumulation of glucose and maltose and a two-step fermentation process: lactic acid fermentation and alcoholic fermentation with ethanol as the main end product. Only transient accumulation of glucose was observed in TwS-injera, and equimolar concentrations of lactic acid and ethanol were produced simultaneously. Final α-galactoside concentrations were low in all sourdoughs. Phytic acid (IP6) was completely hydrolyzed in WrS and BW-injeras probably due to the combined action of endogenous malt and microbial phytases. Only 28% IP6 hydrolysis was observed in TwS injera. Ways to improve IP6 hydrolysis in TwS-injera need to be investigated.
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