Salt reduction in bread – Sourdough as a promising solution

The dietary intake of sodium chloride (NaCl) has increased considerably over the last few decades due to changes in the human diet leading to an increase in a number of diseases including hypertension and other cardiovascular health problems [1]. Numerous international health agencies, as well as the food industry, have now recommended a NaCl intake level of about 5–6 g daily, approximately half the average current daily consumption level. Cereal products, and in particular bread, are a major source of NaCl in the human diet of industrialised countries [2]. Therefore, any reduction in the concentration of NaCl in bread would have a major impact on global health. However, NaCl is a critical ingredient in bread production, and its decrease can have a deleterious effect on the production process. This includes an impact on dough handling as well as final bread quality characteristics, such as shelf-life, bread volume and sensory characteristics. In the present study, the impact of NaCl reduction on the dough characteristics was assessed using fundamental and empirical rheological analyses as well as the influence of salt reduction on yeast regarding the aroma profile during proofing. Furthermore, the quality characteristics of the breads were assessed as well as the analyses of the major bread aroma compounds using GC2-MS. Decreasing NaCl addition from current usage levels (1.2 %) 0.6 %, 0.3 % and 0.0 % reduced the dough resistance to extension, extensibility and complex modulus without affecting the ratio of liquid to solid behaviour. An increasing amount of NaCl of 2.0 %, 3.0 % and 4.0 % Changes in gas holding capabilities of doughs with NaCl concentrations between 0.0% and 4.0 % were observed, however affecting the final bread quality for NaCl levels > 0.6 % only. The incorporation of sourdough fermented with Weisella cibaria MG1 and Lactobacillus reuterii FF2 at levels of 10–20 % compensated changes in bread volume and structure. Decreasing amounts of NaCl resulted in major changes regarding microbial shelf-life as well as the analysed aroma compounds. Depending on the amount of NaCl the shelf-life was shortened by 1 to 2 days (NaCl < 1.2 %) and prolonged by 1 to 2 days (NaCl > 1.2 %) respectively. The addition of sourdough fermented with the specific Lactobacillus amylovorus DCM 19280 producing antifungal compounds at a level of 5 % could compensate the lack of salt whereas the addition of 20 % prolonged the shelf-life up to 14 days independent of the NaCl concentration. Differences of aroma profiles could be determined using GC2-MS analyses. The analysis was focused on the compounds which are synthesised through the Ehrlich pathway by yeast cells. With increasing amounts of NaCl in the dough less aroma compounds could be detected. Overall, breads produced with reduced amounts of NaCl (0.3 % and 0.6 %) were found to be comparable to the control (1.2 % NaCl) in terms of dough and bread characteristics and baking performance whereas sensory attributes and aroma profiles showed clear differences between the NaCl concentrations. Sourdough was assesse

Antifungal lactic acid bacteria with potential to prolong shelf-life of low salt bread

Mean daily salt intakes of populations in developed countries are well in excess of dietary needs (ca. 3-4 g salt/day). Hypertension, a causal factor for cardiovascular diseases, was shown to be caused by increased amounts of sodium, which is mainly applied as sodium chloride (table salt). Up to 35 % of the daily salt intake is contributed by cereal products, in particular bread. Hence, low-salt bread is one of the most efficient ways to decrease the daily salt intake. The technological process of bread baking as well as some of the final quality characteristics of bread, in particular shelf‑life is influenced by salt reduction. Chemical preservatives, e.g. calcium propionate (CP) are commonly used as antifungal agents. Alternatively, sourdough can be used to retard mould growth. This work addresses the feasibility of salt reduction in wheat bread from 2.0 %* (standard) to 1.0 % (sodium‑reduced), 0.5 % (low‑sodium) and 0.0 % (sodium‑free) from shelf-life perspective. The results were compared to those obtained using 0.5 %* of CP and 20 %* of sourdough fermented by the antifungal strain L. amylovorus DSM 19280. The antifungal “in situ” tests were performed under bakery environmental conditions as well as using challenge tests against F. culmorum, A. niger and P. expansum. Mould growth on the bread slices was observed throughout 14 days of storage. For the environmental trials, a shelf-life of about 5 days was obtained for standard bread (2.0 % salt) while breads elaborated with lower salt concentration were spoiled after 3 days. Sourdough addition prolongs the shelf-life at least up to 12 days and the addition of 0.5 % CP prolonged the shelf‑life 10‑12 days compared to the respective controls without any significant differences regarding the salt levels. Concerning the fungal challenge tests, the spoilage was influenced, with different extent, by both salt level and the fungi tested. Generally, similar antifungal performance was observed in sourdough breads and CP breads when tested against the indicator moulds. The findings of this study indicate that addition of sourdough fermented with the antifungal L. amylovorus DSM 19280 can replace CP addition needed to assure the safety of low-salt bread

The effect of sourdough and calcium propionate on the microbial shelf-life of salt reduced bread

The consumption of low-salt bread represents an efficient way to improve public health by decreasing cardiovascular health issues related to increased intakes of sodium chloride (NaCl). The reduction of NaCl influences the bread quality characteristics, in particular the shelf-life. Calcium propionate (CP) is commonly used in bread as an antifungal agent. Alternatively, sourdough can be used as a natural preservative. This work addresses the feasibility of NaCl reduction in wheat bread focussing on shelf-life and the compensation using sourdough as well as chemical preservatives. The impact of NaCl reduction and the addition of preservative agents in conjunction with different NaCl concentrations on the shelf-life of bread were tested under ‘environmental’conditions in a bakery as well as using challenge tests against selected fungi. The challenge tests were performed using fungi commonly found in the bakery environment such as Penicillium expansum, Fusarium culmorum and Aspergillus niger. NaCl reduction decreased the shelf-life by 1–2 days. The addition of sourdough with antifungal activity prolonged the shelf-life to 12–14 days whereas the addition of 0.3 % calcium propionate prolonged the shelf-life to 10–12 days only. The fungal challenge tests revealed differences in the determined shelf-life between the different fungi based on their resistance. Similar antifungal performance was observed in sourdough breads and calcium propionate breads when tested against the different indicator moulds. The findings of this study indicate that addition of sourdough fermented using a specifically selected antifungal Lactobacillus amylovorus DSM 19280 can replace the chemical preservative calcium propionate addition and compensate for the reduced level and, therefore, guarantee the product safety of low-salt bread