Can I double ferment NATTO, to get 4x-10x Natto from Soybeans ?? (After 24 hours, mix whole beans, ferment another 24 hours)

Question

Do commercial Natto-KINASE makers use this method??
(Double ferment NATTO: After 24 hours, mix whole beans, ferment another 24 hours, which mixes up the body of each soybean.)

It appears to me that when making Natto, only the surface of the beans is growing the bacteria. If so, it seems a waste to just mix it up as-is and use the whole beans that are now just coated with the Natto bacteria.

Why not RE-mix the finished natto, which would expose the whole soybean body inside to the bacteria?? Seem like in 24 hours, you'd have massively more finished natto and Natto-KINASE, if you are fermenting specifically for the bacteria / enzymes.

To obtain 1,500 FU units of Natto-KINASE, supposedly I need 50 g / 2 oz of natto. So, to take as a twice daily dose, that would mean I'd have to eat at least 4 oz per day of mixed up Natto and whole soybeans, = 3,000 FU. It seems that the commercial producers must not be using only the outside of the soybean, and ignoring the main body of the soybean.

Do you know if they are doing what I'm suggesting, mixing and inoculating WHOLE bean contents, once the first 24 hours created the "soybean surface-only created natto"? If so, they would either need a lot of "starter", or use the just created new Natto do inoculate the wholly mixed up and pureed batch.

A 50 g serving of natto provides 1,500 FU of nattokinase. The enzyme can withstand temperatures of up to 50°C (122°F) and repeated freezing and thawing, but it is inactive in acidic conditions. Microencapsulated and enteric-coated formulations have been developed to reduce degradation of nattokinase by gastric acid. -- Dabbagh 2014 ---> > SOURCE: https://www.drugs.com/npp/nattokinase.html

Answer 1

I had cross-posted this on Reddit.com/r/Fermentaion and got an answer, which I am posting here. If you want to follow that post instead, go to: https://www.reddit.com/r/fermentation/comments/1jg10cj/comment/mj2fjb6/?context=3

ScottRoberts79 4d ago

Google “nattokinase production methods”. It appears the leading methods include soybean meal and continuous glucose feeds to promote cell growth.

u/DaaBoss DaaBoss OP

Thanks! Why I didn't go down the path of looking up the commercial methods, surely escaped me.

I didn't find your sources, but I think I may have found enough in a few of the Google patents.

I still have one remaining question: HOW ESSENTIAL is OXYGEN to the FERMENT??

I will try it without added aeration first, and see if the filaments are much more widespread after the 2nd ferment.

One of them says that after cooking / cooling, they make a mash slurry, much like you'd do to make beer. Then, they let that ferment after inoculation for 24 - 40 hours, while stirring and AERATION. When finished, they centrifuge out the water, using a micro filter, which I assume is optional. Then they freeze dry the mixture, and then crush it into a powder. What they end up with, is a powder that is about 20,000 PER GRAM! Note that the first ferment is predicted to only provide 30 FU's per gram. (50 Gm = 1,500 FU) So, that is about 660 times as potent, or maybe about 300 times more, if you remove the water.

For me, I think I will try the double ferment. After the first, I will just make a mash, maybe by adding some of the sterile water from the initial boil, using my Instant pot. Then, ferment for the extra 24 hours. Then, I will freeze the mash mixture. I'd think that getting the water out by drying the mixture could cause contamination, and you'd also need to first, stop the ferment. So, freeze drying appears as the only option. I'll try eating about a gram / day, since I can't put watered products in my enteric capsules.

One caution on Natto in general: Depending on the specific type of the natto bacterial, and/or other contaminants, 239 amino acids are created, with various effects. The paper suggests ways to make Natto and other ferments like this, safer:

https://www.researchgate.net/publication/331335649_Bacterial_Production_and_Control_of_Biogenic_Amines_in_Asian_Fermented_Soybean_Foods Bacterial Production and Control of Biogenic Amines in Asian Fermented Soybean Foods - February 2019 - Foods 8(2):85 - DOI: 10.3390/foods8020085