Soy sauce is not only one of the world’s oldest condiments, it’s also one of the most popular – we consume at least eight million tonnes of it per year! But what gives soy sauce its complex salty, umami flavour that makes it so delicious?
Researchers have published new work in the Journal of Agricultural and Food Chemistry, uncovering the proteins and compounds that gives the sauce its distinct flavour.
Soy sauce originated in China more than 2,500 years ago, and is made by fermenting a combination of salt, enzymes and mashed soybeans. However, no complete profile of its flavour agents has been produced yet. Decoding the flavours of this fermented food is particularly challenging because of the complex processes involved in its creation, including the microbial breakdown of compounds over time.
A team of scientists carried out a full assessment of soy sauce’s flavour profile, identifying 34 key tastants – a chemical that produces a taste sensation by activating taste receptor cells (TRCs) and taste-related pathways of the nervous system.
They then combined these compounds to try to recreate the taste of soy sauce. But a panel of 27 assessors found that this recreation did not taste quite right – it was missing something.
The team hypothesised that small proteins could be missing from its batch, and used a senso-proteomics approach to identify 14 umami, kokumi and salt-enhancing peptides, present in concentrations of between 166–939 μmol/L .
The addition of these to their artificial soy sauce of now over 50 flavour compounds produced a condiment with comparable complexity, taste intensities and “mouthfulness” to the real deal. Some of the salt-enhancing proteins gave a salty sensation, which had only previously been brought on by table salt and other minerals. These salt-flavoured peptides could potentially serve as a seasoning alternative to table salt that could be better for your heart.
This greater understanding of why soy sauce tastes the way it does could help in tailoring the growth or manufacturing processes to better ensure consistent quality, and also boost certain flavours.
Qamariya Nasrullah holds a PhD in evolutionary development from Monash University and an Honours degree in palaeontology from Flinders University.
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