Acid Protease for Soy Sauce & Seasoning
Reliable protein breakdown for the moromi stage, where umami is actually built.
Soy sauce, miso and savoury seasoning bases all depend on the same underlying event: soybean and wheat protein being broken down into the peptides and free amino acids that carry umami flavour. In traditional fermentation, koji mould enzymes do this work over weeks to months, and the result is only as consistent as the koji batch that produced it. Acid protease is used to support and stabilise that breakdown during the acidic moromi stage, supplementing the koji's own proteolytic activity so a batch is less at the mercy of mould variability. It works at the low pH the moromi mash already sits at, so it fits into an existing process rather than asking the process to change for it. Manufacturers use it to protect flavour development in batches with weaker koji activity, to support faster-cycle or lower-salt formulations where less time is available for natural proteolysis, and to keep protein utilisation consistent from batch to batch. We supply acid protease in bulk for seasoning and condiment fermentation, with samples available to trial against your own moromi.
Soy sauce moromi fermentation
During the moromi stage, soybean and wheat protein is broken down into the amino acids and peptides responsible for umami and body. Supplementing proteolysis here helps protect flavour development when koji activity varies batch to batch, and can support consistency across a production run.
Miso and paste-style seasonings
Miso relies on the same underlying proteolysis, over a fermentation that can run considerably longer than soy sauce. Acid protease is used to support protein breakdown in the early stages, ahead of the slower flavour-maturation that follows.
Faster-cycle and lower-salt formulations
Shortening fermentation time or reducing salt both tend to leave less time and a less favourable environment for natural proteolysis to complete. Supplemental acid protease is one of the tools used to keep protein utilisation on track under those tighter conditions.
Savoury seasoning bases and bouillon
Beyond soy sauce and miso, the same hydrolysis principle applies to other fermented and enzymatically hydrolysed savoury bases used in seasoning blends and bouillon manufacture, where a controlled, repeatable amino acid profile is the goal.
Frequently Asked Questions
Does this replace koji in soy sauce production?
No. It supplements the koji's own proteolytic enzymes rather than replacing the fermentation. Koji still carries out the broader biotransformation; acid protease is used to support and stabilise the protein-breakdown step specifically, especially where koji activity is inconsistent.
Why an acid protease rather than a neutral one for this application?
The moromi stage runs acidic. An enzyme chosen to work at that pH stays active through the stage it is needed for, rather than losing effectiveness as the mash acidifies.
Can it help with lower-salt formulations?
Reduced salt changes the fermentation environment and can slow natural proteolysis. Supplemental acid protease is one of the levers used to help protein breakdown keep pace under those conditions, alongside other formulation adjustments.
Where in the process is it added?
Typically during the moromi or early mash stage, where temperature and pH suit enzyme activity. The right point depends on your specific process and fermentation schedule.
Can we trial it on our own batch first?
Yes. We supply samples for trial fermentations so you can evaluate the effect on your own koji, mash and schedule before committing to bulk volumes.
Trial acid protease on your own moromi
Provide substrate type, process pH and temperature, and desired hydrolysis outcome. We’ll recommend grade (50k or 100k U/g), ship a 100 g trial with COA, and quote for 25 kg drums within 24 h.
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