Introduction
Mean daily salt intakes of the population in developed countries are well in excess of their dietary needs (ca. 3–4g salt/day) (European Food Safety Authority 2005). One of the effects of the high salt intake is hypertension, which is seen as a causal factor for cardiovascular diseases (Elliott et al. 1996). Up to 35 % of the daily NaCl intake is attributed to cereal products, where bread plays the most important role (Angus 2007). Hence, low-salt bread is one of the most efficient ways to decrease the daily NaCl 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 NaCl level. Bread is known as a high moisture product with aw values between 0.96 and 0.98 (Smith et al. 2004). As demonstrated by Doerry (1990), microbial spoilage is the main cause for shelf-life issues in intermediate and high moisture food products. Nowadays, mould growth is still a cause of high losses to the bread-producing industry (Legan 1993; Corsetti et al. 1998; Smith et al. 2004; Pateras2007).
Many references show that fungal spoilage is not a current problem in baking industry but causing trouble and losses since decades (Jarvis 1972; Knight and Menlove 1961; Legan 1993; Filtenborg et al. 1996; Pateras2007; Samapundo et al. 2010). Knight and Menlove (1961) could show that mould spores are killed during the baking process and the issue limiting the long-term shelf-life of bread is a post-baking fungal contamination. Sodium chloride (NaCl), commonly called salt, acts as a preservative agent in bread due to its ability to reduce the water activity (aw). Increased osmotic pressure causes cells to lose water to the environment, thus inhibiting cell growth. Up to date, research on NaCl reduction was mostly focussed on changes in flavour and the impact on dough properties influencing the production process. Hence, little is reported about influences on microbial shelf-life of bread due to reduction of NaCl. The present work aims to determine the influence of NaCl reduction on the microbial shelf-life of wheat bread as well as to present some possible feasible solutions.
IntroductionMean daily salt intakes of the population in developed countries are well in excess of their dietary needs (ca. 3–4g salt/day) (European Food Safety Authority 2005). One of the effects of the high salt intake is hypertension, which is seen as a causal factor for cardiovascular diseases (Elliott et al. 1996). Up to 35 % of the daily NaCl intake is attributed to cereal products, where bread plays the most important role (Angus 2007). Hence, low-salt bread is one of the most efficient ways to decrease the daily NaCl 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 NaCl level. Bread is known as a high moisture product with aw values between 0.96 and 0.98 (Smith et al. 2004). As demonstrated by Doerry (1990), microbial spoilage is the main cause for shelf-life issues in intermediate and high moisture food products. Nowadays, mould growth is still a cause of high losses to the bread-producing industry (Legan 1993; Corsetti et al. 1998; Smith et al. 2004; Pateras2007).Many references show that fungal spoilage is not a current problem in baking industry but causing trouble and losses since decades (Jarvis 1972; Knight and Menlove 1961; Legan 1993; Filtenborg et al. 1996; Pateras2007; Samapundo et al. 2010). Knight and Menlove (1961) could show that mould spores are killed during the baking process and the issue limiting the long-term shelf-life of bread is a post-baking fungal contamination. Sodium chloride (NaCl), commonly called salt, acts as a preservative agent in bread due to its ability to reduce the water activity (aw). Increased osmotic pressure causes cells to lose water to the environment, thus inhibiting cell growth. Up to date, research on NaCl reduction was mostly focussed on changes in flavour and the impact on dough properties influencing the production process. Hence, little is reported about influences on microbial shelf-life of bread due to reduction of NaCl. The present work aims to determine the influence of NaCl reduction on the microbial shelf-life of wheat bread as well as to present some possible feasible solutions.
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