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This study aimed at investigating the antifungal activity of Wickerhamomyces anomalus and sourdough lactic acid bacteria to extend the shelf life of wheat flour bread. The antifungal activity was assayed by agar diffusion, growth rate inhibition, and conidial germination assays, using Penicillium roqueforti DPPMAF1 as the indicator fungus. Sourdough fermented by Lactobacillus plantarum 1A7 (S1A7) and dough fermented by W. anomalus LCF1695 (D1695) were selected and characterized. The water/salt-soluble extract of S1A7 was partially purified, and several novel antifungal peptides, encrypted into sequences of Oryza sativa proteins, were identified. The water/salt-soluble extract of D1695 contained ethanol and, especially, ethyl acetate as inhibitory compounds. As shown by growth inhibition assays, both water/salt-soluble extracts had a large inhibitory spectrum, with some differences, toward the most common fungi isolated from bakeries. Bread making at a pilot plant was carried out with S1A7, D1695, or a sourdough started with a combination of both strains (S1A7-1695). Slices of the bread manufactured with S1A7-1695 did not show contamination by fungi until 28 days of storage in polyethylene bags at room temperature, a level of protection comparable to that afforded by 0.3% (wt/wt) calcium propionate. The effect of sourdough fermentation with W. anomalus LCF1695 was also assessed based on rheology and sensory properties.The major problem for long-term shelf life of baked goods is contamination with fungi. Although they are used as the main chemical preservatives, salts of propionic, sorbic, and benzoic acids have shown several drawbacks. Reports on the appearance of cancer-like tumors in rats fed with propionic acid at concentrations of up to 4% led to prohibition of the use of calcium propionate in some European countries (31). Prolonged preservation of breads with high concentrations of calcium propionate stimulated the growth of resistant strains of Penicillium roqueforti (42). Since a few years ago, the European directive on preservatives (18) decreased the permitted concentrations of sorbate and propionate to 0.2 and 0.3% (wt/wt), respectively. Ethanol is also permitted as an antifungal preservative (2% [wt/wt]). Its inhibitory effect varies depending on the fungal species, and in some cases, it is not sufficient to prevent contamination (14).Several studies have focused on the antifungal activity of compounds from natural sources and on biopreservation as effective alternatives to chemical preservatives. Several antimicrobial compounds have been identified, especially proteins or peptides from plants, as well as metabolites derived from fermentation by lactic acid bacteria (12,23,25,42,43). Besides acidification during sourdough fermentation, lactic acid bacteria also synthesize a wide range of low-molecular-weight compounds (27), peptides (28), and proteins (10, 37) with antifungal activity. Unfortunately, only a few studies have assessed their inhibitory activity under bread-making conditions. Recent studie...

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Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5, isolated from wheat germ and selected based on the kinetics of acidification, were used as starters for the manufacture of sourdough fermented wheat germ. A bread containing sourdough fermented wheat germ as an ingredient (SFWGB) was compared to breads made with (raw wheat germ bread, RWGB) or without (wheat flour bread, WFB) raw wheat germ. The higher concentration of free amino acids mainly differentiated SFWGB from WFB and RWGB. The in vitro protein digestibility of WFB was the highest, even if sourdough fermentation of wheat germ attenuated the difference. Phytase and antioxidant activities of SFWGB were highest. The specific volume and cell-total areas were also the highest for SFWGB. As determined by texture profile analysis, the values of hardness, resilience and fracturability of breads containing wheat germ were lower than those found in WFB. The crust lightness showed a decrease from WFB to SFWGB. As determined by sensory analysis, SFWGB had mainly acid taste and flavour and resulted more salty. Sourdough fermented wheat germ is an ingredient able to enhance nutritional, texture and sensory properties of bread

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