Cross-modal interactions between taste and smell: Odour-induced saltiness enhancement depends on salt level

In recent years, health concerns related to salt have led to extensive research on low-salt foods. One major remaining issue is to reduce sodium content while still providing the salty fix, to maintain food appreciation, acceptance and choice. Using well-selected odours has been proposed to compensate for sodium chloride reduction in food, due to the cross-modal interactions between odour and taste. However, interactions between taste and odour, with regards to saltiness, remain poorly investigated. Moreover, although a few studies have assessed the influences of odour and sweet supra-threshold intensity on cross-modal interactions, none focused directly on how they influence saltiness. Therefore, the aim of the present study is to determine if the level of saltiness, i.e., the concentration of sodium chloride in aqueous solutions, influences odour-induced saltiness enhancement (OISE). A panel of 64 untrained panellists evaluated the saltiness of water solutions including salt and a tasteless odorant. Following a full factorial design, three concentrations of salt were used in conjunction with three aroma conditions. The results confirmed that OISE depends on odour–taste congruency but also clearly indicated that OISE depends on salt concentration (salty intensity): the saltiness of a low- or medium-salt-content solution increased significantly when subjects perceived simultaneously the congruent sardine aroma, but OISE was no more significant with high-saltiness solutions. This effect has to be taken into account when using OISE as a compensation strategy in low-salt food.

► Interactions between salty taste and odour are investigated.
► OISE depends on odour–taste congruency and also on salt concentration.
► Saltiness of low or medium salt content solution increased with the congruent sardine aroma.
► OISE was no more significant with high salt-content solutions.
► This result is especially relevant while using OISE as a sensory compensation strategy in low-salt food.