As one of the basic food staples around the world, bread also contributes to the daily salt intake. Lowering dietary sodium chloride levels is a priority worldwide, but its vital role in bread’s quality should not be overlooked when lowering and replacing its levels.

 Bread is one of the oldest foods in the world. It is a part of the foodstuffs that are the basis of many people’s diets due to its nutritional value and the low price, a reflection of both the raw materials used and the technology applied. Nutrition experts define bread as an essential part of the food pyramid’s base due to its rich content in carbohydrates, fiber, proteins, B vitamins and mineral salts, and its very low-fat content (Silow et al., 2016).

Nowadays, the dietary sodium chloride intake is higher than the daily-recommended levels, especially due to its prominent presence in food products. This may cause an increase in high blood pressure leading to cardiovascular diseases. In most European countries, bread is the most important source of salt, its contribution to salt intake ranging between 19.1% in Spain to 28% in France (Gebski et al., 2019).  Considering a standard bread recipe (60g water, 2g salt and 100g flour), the aqueous phase contained in the bread has the same salt content as seawater (ca. 33g/l); in other words, eating 100g of bread is the equivalent of an intake of 38ml of seawater (in terms of saltiness intake); quite shocking, isn’t it? Salt reduction is, therefore, a great stake for all health authorities over the world. However, salt is a critical ingredient in bread making, and its reduction can have a negative impact on bread quality (Codina et al., 2021).

Salt (sodium chloride) plays a major role in bread making. It contributes to bread palatability, water holding and also to setting a visco-elastic network. All steps of the bread-making process are impacted by salt. Fermentation, for example, is delayed due to osmotic stress, resulting in reduced yeast activity. Salt also contributes to the shelf life of bread, which is extended with increasing salt content. Finally, salt contributes to the organoleptic qualities of bread.

This paper presents an investigation carried out during the Ph.D. project of Doina Crucean under the supervision of Dr.Patricia Le-Bail (INRAE-BIA-Nantes-France), Prof. Alain Le-Bail (ONIRIS-GEPEA Nantes-France) and Dr. Gervaise Debucquet (AUDENCIA-Nantes-France), with the objective of developing bread reduced in salt using choline chloride (CC) and to assess the consumer’s acceptance of such bread. The challenge of this strategy is to solve the technological and sensory problems caused by sodium chloride removal from bakery products recipes.

 Choline Chloride is able to act as a substitute for salt (NaCl). Choline (E1001) is presented as an emulsifier in the additive list of the EU commission. It also includes B4 vitamin. Nutritionally, choline chloride is an essential nutrient of vital biological importance. Choline holds 3 European Health Claims (UE 432/2012); it “Contributes to the metabolism of homocysteine”, “Contributes to lipid metabolism” and “Contributes to hepatic function”. It is thus an ingredient beneficial to health. Choline is marketed under different salts, such as choline-chloride (CC) (E1001iii), which has been used for this project. CC is temperature-resistant (melting temperature 247°C) and is therefore adapted to baking. It is acknowledged as ‘Generally Recognized as Safe’ (‘GRAS’) by the FDA.

 The impact of Choline Chloride on the main characteristics of bread

Locke and Fielding (1994) first pointed out the interest of CC to reduce salt in food. Le-Bail et al (2013) showed that 50% salt reduction was possible in pizza dough by adding 25% of nominal salt. Based on this study, a similar recipe has been used in this project.

Choline chloride allowed a significant reduction of salt and had less impact on yeast activity. In an aqueous solution, the CC behaves like an ionic liquid and causes a reorganization of the internal structure of the starch grain. The staling study highlighted the positive effect of CC on bread texture and the retrogradation of starch. Indeed, the CC restricts the recrystallization of amylopectin due to less availability of water in the medium and decreases the staling kinetics of the bread. Choline chloride may also act as an anti-staling ingredient since it behaves as an ionic liquid in an aqueous solution and may contribute to starch depolymerization. An in-depth study was done to assess the anti-staling effect with different levels of CC concentration. Several technics were used (X-ray diffraction, calorimetry) with a kinetics approach to assess the impact of CC on starch during mixing, baking and storage/staling.

Conclusion

The use of choline chloride as a salt substitute has the potential to provide improvements in breadmaking, due to its effect on the gelatinization of starch and its power to increase the perception of salty taste. So far, only two studies have demonstrated the possibility of using choline chloride to enhance the salty taste of foods (Locke & Fielding, 1994; Le Bail et al., 2013), and no study had been carried out on its use in actual production.

Among the main results, we note that choline chloride causes a reorganization of the internal structure of the starch grain; it restricts the recrystallization of amylopectin due to the reduced availability of water in the medium and decreases the rate of stale bread. On the sensory level, it increases the perception of salty taste, but in a moderate way. Thus, the obstacles to the societal acceptability of CC bread are found both on the sensory and on the cultural level.

Acknowledgments: This project was co-funded by ONIRIS (Ministry of agriculture), INRA-BIA and ONIRIS-GEPEA within the ID4FOOD program.

 Authors:

P. LE-BAIL a,c, D. CRUCEAN b,c, C. JONCHERE a,c, B. PONTOIRE a,c, G. DEBUCQUET d, A. LE-BAIL b,c,

a INRAE-BIA, UR-1268 Biopolymères Interactions et Assemblages, rue de la Géraudière, 44316 NANTES, France

b ONIRIS, GEPEA, UMR CNRS 6144, rue de la Géraudière, CS 82225, 44322 NANTES CEDEX 3, France

c SFR 4204, Ingénierie des Biopolymères pour la Structuration des Matrices et des Matériaux (IBSM), 44316 NANTES, France

d Audencia Business School, 8 Route de la Joneliere, BP 31222, F-44312 Nantes, France

Read more about the paper in Baking  + Biscuit International, Issue 6 – 2021.