The relationship betwen NaCl concentration and taste perception of saltiness in bread

Background – Sodium (Na+ ) is present in food in the form of sodium chloride (NaCl). There is strong evidence that high dietary Na+ intakes increase the risk of developing various adverse health conditions. Many international organisations encourage Na+ reduction in both the diet and the food supply. One of the major dietary sources of NaCl is bread, where NaCl has the essential function of imparting flavour. At present, no literature has been published examining taste interactions that may play a role in limiting the maximum saltiness perception in bread.
Objective – To determine the extent the physical structure of bread inhibits salty taste perception. Additionally, to determine whether common commercial bread additives suppress saltiness of bread.
Design – Subjects (n=14, 12 females) tasted and rated samples with varying NaCl concentrations in water (0 – 1724 mg NaCl/100 g) and bread (125 – 1550 mg NaCl/100 g) using the general Labelled Magnitude Scale. Psychophysical curves plotting NaCl concentration against NaCl intensity were constructed for water and bread. Breads of fixed NaCl concentration (1125 mg NaCl/100 g) and various common additives (sucrose, soya flour, canola oil, gluten) were also rated to assess perceived saltiness.
Outcomes – There was a significant difference between Na+ psychophysical curves in water and bread (P<0.05) with the bread matrix suppressing maximum possible saltiness by 25% to 70%. Suppression of saltiness was observed after the addition of sucrose (55% decrease) or soya flour (60% decrease) during bread production compared to prototypical bread (both P<0.05).
Conclusions – The physical structure of bread and some common additives have a major influence on perceptual saltiness of bread. The removal of additives that suppress saltiness combined with strategies to modify the texture of bread could lead to significant reduction in dietary Na+, whilst maintaining optimal salty taste.