Salt distribution in food influences salt perception
Résumé
Salt (NaCl) consumption is recognized as an important factor in the rise of hypertension in industrialized countries. Therefore, health authorities recommend a reduction of 20% of salt content (generally salt is present about 0.5 to 2g per 100g of food) in several food products such as ready meals and snacks. However, salt reduction in processed foods induces numerous technical difficulties since salt has a number of functions: preservation, water and fat binding and flavour enhancement. Indeed, salt gives a salty taste that guarantees food palatability. The present study is in line with global research to reduce salt level in foods while maintaining saltiness. The aim is to evaluate the influence of salt distribution on salt perception, in a complex food matrix. The model food includes two distinct layers: the lower layer is a pastry and the upper layer is made of a semi-solid custard. The influence of salt distribution within the two layers has been studied through a full factorial design including two factors: concentration of salt added in the lower layer and the upper layer (without salt, 0.3 and 1g per 100g). Saltiness intensity of the 9 products was rated by a panel of 87 naive consumers. The total salt concentration in each product was checked by HPLC (High Performance Liquid Chromatography). Results showed that salt concentration impact saltiness but differently according to the layer. Salt concentration variation induces much more difference in salt perception in the upper layer (F(2, 672)=664, p<0.0001) as compared to the lower layer (F(2, 672)=4.7, p=0.01). As a consequence reducing salt level in the upper semi-solid custard layer led to a drastic decreased in saltiness while reducing salt in the pastry layer did not. In conclusion, these results demonstrate that a heterogeneous distribution of salt in real food products could be used to maintain organoleptic characteristics of reduced salt food.