Functional salt substitute: Salt reduction in bread using choline chloride

A MULTIFUNCTIONAL SALT SUBSTITUTE

Salt reduction in bread using choline chloride

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.

CC 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 temperatureresistant (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 (Figure 1).

RECIPES

Figure 1: The CC Bread was reduced in salt by 50%

Choline chloride allowed a significant reduction of salt and had less impact on yeast activity than salt. 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. The impact of CC on staling (evolution of the amount of retrograded amylopectin during storage) and evolution of texture of bread are shown in Figure 2 below showing the interest of CC in improving the softness of bread using CC in their formulation.

Other tests were done with a mixing cell (SETARAM, Caluire France) used in differential scanning calorimetry (DSC) to measure the thermal effect of water, salt and CC on starch during mixing. This technique made it possible to determine not only the heat of rearrangement of the amylopectin molecules of starch, but also the energy related to the dissolution of choline chloride at room temperature, and to conclude that in the presence of choline chloride in the mixture, CC took priority over the starch in front of the water.

Source: Locke and Fielding (1994)

Impact of Choline Chloride on the sensory and societal acceptability of CC bread

On a sensory level, it has been shown that there is an increasing trend in the perception of salty taste with the increase in the content of choline chloride (Figure 2). However, the amount

Figure 2: Left Evolution of the retrogradation enthalpy of amylopectin during storage at 4°C. Right Evolution of the texture of breads during storage at 4°C

Source: Locke and Fielding (1994)

Product Formulation

Figure 3: Sensory ranking test: the impact of choline chloride (CC) on the perception of the salty taste of a reduced-salt bread with 50%. Values are given as a % of nominal salt (% NS) which corresponds to 1.8g of salt per 100g flour

Source: Locke and Fielding (1994)

of choline chloride used in the recipe seems insufficient to fully satisfy the consumer looking for the salty taste identical to the reference bread (Crucean et al., 2019).

The acceptance of CC bread, investigated in focus groups, identified three groups of consumers likely to consume it: health-oriented young people, young parents who want to educate children to engage in a healthy lifestyle, and people broadly sensitive to nutritional information. In terms of acceptability, the nutritional qualities of this bread appeal to consumers who favor health in their food choices and those aspiring to strong food education. Alternatively, among consumers who are very sensitive to the traditional values associated with bread, the ‘functionalization’ or ‘nutritionalization’ of this food constitutes a major obstacle to its consumption (Crucean et al., 2019).

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, obstacles to the acceptability of CC bread were found on the sensory level and also on the cultural level. As an example, the labeling 'choline chloride bread' appeared suspicious to consumers thinking that CC is an additive whereas it is an essential nutrient, and the alternative labeling 'bread containing vitamin B4' was understood by some consumers as a medicinal bread which appeared also as suspicious.

This work constitutes an original scientific contribution, with a real technological stake and obvious industrial applications. Indeed, the theme aims to respond to the demand for reducing the consumption of salt in processed products, as recommended by the health authorities and the World Health Organization, but also to an increasingly strong societal demand to consume products with less impact on health.

In conclusion, CC is a relevant alternative to salt that combines technological and sensory benefits; its success will depend on the consideration of issues related to social acceptability. +++

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 Corresponding author: patricia.le-bail@inrae.fr

Reference

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