UMTaste: Understanding the mechanisms by which umami taste influences salty and bitter taste to enable umami to drive salt reduction and improvement i

The UK has been prioritising salt reduction since 2004 in response to the Scientific Advisory Committee on Nutrition (SACN) 2003 report on salt and health. In addition, the National Food Strategy has recommended eating less meat to reduce methane emission. Salt (NaCl) is used in foods for taste, preservation (reducing water activity), and for its impact on structure. Salty taste remains the predominant driver for salt in many foods. Research has focused on finding sodium replacers (e.g. KCl), or extending salty taste (e.g. controlling salt distribution within a food matrix). Such strategies are limited. Another approach is to use umami taste (UT), the savoury taste associated with compounds such as monosodium glutamate (MSG). Umami and salty are perceived through the activation of different receptors. NaCl activates ion channels (eg epithelial sodium channel, ENaC), umami tastants activate type 1 G-protein coupled receptors (eg T1R1-T1R3 heterodimer). Compounds such as 5'-nucleotides act synergistically on glutamate, enhancing T1R1-T1R3 response. UT has been shown to enable salt reduction in numerous foods; although in most studies the outcome measure was palatability rather than matched salty taste(1). Beyond salt, understanding and controlling the contribution of UT to overall taste may lead to improvements in plant-based protein foods through savoury taste and reduction in characteristic bitter taste. Umami fractions (from soy sauce) rich in amino acids and glutamyl peptides were demonstrated to reduce bitter perception and suppress activity of specific bitter taste receptors (T2R-GPCRs)(2).

However, the mechanism by which UT enables salt reduction and bitter suppression remains inconclusive. Our group has investigated the interaction of UT from glutamate with four other basic tastes in equi-intense solutions(3). We concluded that UT did not enhance or suppress the trained panelists' perception of other tastes. This demonstrates how umami is perceptually...