Influence of sodium chloride on colour, residual volatiles and acrylamide formation in model systems and breakfast cereals

Abstract

To elucidate the salt action in breakfast cereals to decrease its amount without a quality loss, a model system was developed. This model, composed of native maize starch, glucose and a mixture of five amino acids (glucose ⁄ amino acids molar ratio = 1 ⁄ 1) generated similar colour and volatiles (m ⁄ z = 45, 59, 69, 73, 87 and 103 g mol )1 ) after heating compared to commercial breakfast cereals. A designed experiment used this model to study the influence of salt concentration (0-5.44%), heating time (0-25 min) and temperature (180-230°C) on colour, residual volatiles and acrylamide formation. The higher the salt concentration, heating time and temperature, the darker were the products (P < 0.05). The L* values of the model systems containing 5 % salt and heated for 25 min at 230°C were twelve points lower than the same systems without salt heated in the same conditions. Presence of salt significantly decreased acrylamide formation in the model systems (up to 50 % decrease when 2.5 % salt is added). However, salt did not have a significant impact on volatile levels. These findings were confirmed by observations made on four types of commercial breakfast cereals.

Influence of salts on starch degradation: Part I – sodium chloride

“…Aliquots of 60 g were placed in open containers and were heated in an oven (Thomas Collins & Co Ltd., Bristol, UK) for 45 min at 230°C. The moisture content of the sample before the heat treatment and the heating temperature were chosen to mimic the toasting step of the breakfast cereals process 6 or to imitate what happens to the bread crust during the baking stage 8. The samples were removed from the oven and left at room temperature for cooling, they were then milled into powders with a mortar.…”

“…Most of cereal‐based products such as breakfast cereal or bread have, at the end of their production process, a final heating step at high temperature in a dry environment. This heat treatment can be for starch gelatinisation (baking step for bread) 5 and/or for the generation of colour and flavour in a product that is already gelatinised (toasting step for breakfast cereals) 6, 7. During these baking or toasting steps, the product dries.…”

“…In contrast, the temperature of the crust can reach about 205°C when the oven temperature remains at a constant zone of 220–240°C 8. The toasting temperatures used for breakfast cereals vary between 180 and 230°C 6. As breakfast cereals are small and thin pieces of starchy products, the entire product dries during the toasting step (no crumb/crust formation) and its temperature should reach the oven temperature by the end of the toasting process.…”

“…Several studies reported that salt influences colour formation in cereal‐based products such as bread, breakfast cereals or in model systems containing glucose, amino acids and starch 6, 7, 13–15. The way salt influences colour formation in starchy products remains unclear.…”

Effect of Inorganic Salts on Acrylamide Formation in Cereal Matrices

“…Indeed, NaCl might slow down the Maillard reaction pathway and lead to acrylamide formation while it could enhance the last few steps of the Maillard reactions to form melanoidins [44]. Regardless of the NaCl concentration, the acrylamide content increased during the first few minutes of toasting, after which acrylamide content remained stable or eventually decreased.…”