exciting tempeh research & development

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exciting tempeh research & development

Postby whalesounds on Tue Oct 24, 2017 12:01 am

hi all, I'm doing some home research on tempeh production that I THINK is fairly novel and wanted to share and fish for any insights yall might have. I'm also gonna use this thread as a place to compile any updates or relevant info.
Here's the basic gist:

Most english-language information on tempeh addresses cold/temperate climate-dwellers, this leaves the contradiction that someone who lives in a subtropical or tropical area (like myself), would be compelled to use fork-poked plastic bags, incubators, and single-strain lab-made cultures when banana trees are a weed, ambient temperatures are perfect for tempeh 6 months of the year, and the cultures may be available in the wild.

From reading a few papers on tempeh, I learned the following:
1. While rhizopus oligosporus is the mold culture sold as "tempeh starter," r. oryzae, r. delemar, and r. stolonifer are also effective. "...utilization of R. stolonifer and R. oryzae as tempeh inoculants, at least, change the texture, aroma and the colour of tempeh " (4)
2. The nutritional contents of tempeh made from these three rhizopus are almost identical, though oligosporus rates subjectively as tastiest (5).
3.. The microbiomes of various southeast asian hibiscus species host the various rhizopus strains responsible for the tempeh mold, and are thus the plant origin of the tempeh culture. (1)
3. The microbiome of hibiscus rosa-sinensis, commonly planted as an ornamental in my area, includes r. stolonifer. (2)
4. Most research on tempeh in its original habitat is not written or translated into english.
5. Rhizopus species are incredibly common in the wild, appearing as various forms of rot. It appears that there are two names for each of the tempeh strains, one for when it is "good" rot and one for when it's "bad." (7)

I also suspect but either can't or haven't yet tested the following:
1. Just as the use of ragi (hibiscus leaves) in tempeh production has been described in some research as a method to "catch" the culture, rather than as its origin, and thus as unnecessary/inconsequential, so may the treatment of banana leaves as a simple convenience overlook them as a possibly important element of the tempeh process. (7)
2. R. Oligosporus may or may not be "better" than the other rhizopus species at making tempeh, but it's isolation simply the result of a colonial/industrializing mindset. It is certainly less common than the other two strains.
3. Various tempeh-producing rhizopus might be obtainable from rotten foods such as papaya (also common in sub/tropics. I got two volunteers in the compost pile) (6, 7)

What I THINK is possible is to use entirely local, cheap/free ingredients to make a gulf coast/caribbean tempeh. We've got beans, we've got bananas, and we've got hibiscus. And we've got ambient temperatures of 80-90F for a significant portion of the year.

Step one: ordered some packets of rhizopus oligosporus from the internet to do my first batch and get a hang of the process. Done and done. Did not use vinegar or an incubator, cut banana leaves from a neighbors yard to package, dehulled black beans with a rolling pin. Added some kelp for fun. "incubated" the tempeh in the unheated oven and then on a rack in the open for 3 days. Looks and tastes perfect.

Step two (not completed): separate trials with soybeans stirring in the following forms of hibiscus leaves:
dried/powdered
extract made from shaking flower carpel (pistil/female part) in boiled and cooled water (chart in (2) shows carpel with highest concentration of r. stolonifer)
water extract from fresh leaves

Unfortunately the temperature just dropped from a daily range of 80-90F, so things probably won't be SO easy as they are earlier in the fall...may end up using a styrofoam cooler for the first stage


Further info sought:
how to ID rhizopus rot in papaya, if it's a particularly bad idea to obtain the culture from rotten vs. healthy plant sources. Whatever I'm missing- I'm going off of biology 101 and my vague ability to interpret these studies. Anyone with a more in depth knowledge about any of this stuff I'd be more than happy to hear from.


sources:

(1)An original habitat of tempeh molds Yoshio Ogawa, Seiji Tokumasu, Keisuke Tubaki. Accessible via Jstor public library access

(2) Mycoflora associated with Hibiscus Rosa-sinensis http://www.zobodat.at/pdf/Sydowia_24_0193-0197.pdf

(3)https://www.milkwood.net/2016/07/18/making-tempeh-village-revitalisation-tool/ Note use of powdered culture.

(4)http://www.sciencedirect.com/science/article/pii/S1978301915000066

(5) Study conducted in Nigeria on feasability of local tempeh production. Comparison of nutritional and subjective qualities of tempeh produced from various Rhizopus strains cultured from local sources. :http://www.sciencewebpublishing.net/ijbfs/archive/2013/December/pdf/Omosebi%20and%20Otunola.pdf

(6) Hosts of "rhizopus soft rot" (r. stolonifer or arrhizus/oryzae) http://www.extento.hawaii.edu/kbase/cro ... _stolo.htm

(7) R. Oligosporus = R. microsporus (rice seedling blight, sunflower head rot, corn ear rot)
R. Oryzae= R. arrhizus. (carrot wooly soft rot, pineapple/mango rhizopus rot, banana soft rot (!!!!!) (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483402/)
r. stolonifer= r. nigricans (black bread mold, many of the same as oryzae)
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Re: exciting tempeh research & development

Postby whalesounds on Tue Oct 24, 2017 12:05 am

also, this is part a larger pursuit of climate-specific, i.e. easy wild cultures appropriate to my area. If anyone else living in subtropical/tropical areas has experiences with cultures that are particularly easy for us, lemme know! I've had great success with dosas and acaraje, am looking to expand beyond the bean-based ferments. Also interested in storage methods beyond refridgeration.
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Re: exciting tempeh research & development

Postby Christopher Weeks on Wed Oct 25, 2017 7:35 am

Neat! I'll be reading as you write more.
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Re: exciting tempeh research & development

Postby kdz001 on Thu Nov 23, 2017 3:41 pm

Very cool project. Some thoughts:

The tempeh molds used in Indonesia have likely undergone some mild domestication, that is they have begun to evolve to be different from wild-types based on human-mediated selection, such as gaining new metabolic pathways to better utilize the starches and proteins of soybeans.

Some species within the Rhizopus genus produce mycotoxins, though most commercial strains seem to not produces any toxins. On the other hand, several Rhizopus, including R. oryzae and R. stolonifer can degrade mycotoxins from other groups of food-spoiling molds, presumably as a form of competitive inhibition/allelopathy. To add even more complexity to the mix, one Rhizopus toxin, rhizoxin, has been shown to be produced by intracellular bacteria, so toxicity may be a matter of the local microbial composition at the time of germination. I’d definitely read up on any toxic potential of any species you are interested in using.

I recently read in the Book of Tempeh that Indonesian tempeh molds are “mixed cultures”, likely containing multiple mold species and/or strains, and invariably, bacteria as well. I have a hunch that the continued viability of the culture and resistance to contamination has to do with this diversity, based on my understanding of diversity and ecosystem function.

I suspect the key to local tempeh culture will be striking a balance of environmental parameters and species composition as opposed to the exact source of the fungi. I probably wouldn’t use anything that clearly smells looks/rotten as their will most definitely be bad bacteria in the mix as well, but other than that I think you’ll just have to experiment and see. If it were me, I would first try to replicate the Indonesian process as much as possible by growing your chosen mold on hibiscus leaves until it sporulates and using the dry spores directly. Also maybe sandwich some uninoculated soybeans between two hibiscus/banana leaves and see if any mold grows (and if so, what kind(s)).

Lastly, if you know anything grad students/professors at the nearest university, you might find someone who knows a little more about local species and phenotypes, or even get some free/cheap lab testing.
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