Tempeh

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Tempeh

Tempeh is a fermented food typically made from soybeans, most popular in Indonesia and other parts of Southeast Asia. Tempeh is similar to tofu in providing a way to improve the digestibility of soybeans, but different from it in nutritional characteristics and eating qualities, as tempeh's fermentation process and its retention of the whole bean give it a higher content of dietary fiber and vitamins, as well as firmer texture and stronger flavor. Tempeh is used worldwide in vegetarian cuisine as a meat analogue.

Production

Tempeh begins with whole soybeans, which are softened by soaking and dehulled, then partly cooked. Specialty tempehs may be made from other types of beans, wheat, or may include a mixture of beans and whole grains.

A mild acidulent, usually vinegar, may be added and a culture containing the spores of fungus Rhizopus oligosporus is then mixed in. The beans are spread into a thin layer and are allowed to ferment for approximately 24 hours at a temperature around 30°C (86°F). In good tempeh, the beans are knit together by a mat of white mycelia.

Under conditions of lower temperature, or higher ventilation, gray or black patches of spores may form on the surface -- this is not harmful, and should not affect the flavor or quality of the tempeh. This sporulation is normal on fully mature tempeh. A mild ammonia smell may accompany good tempeh as it ferments, but it should not be overpowering. In Indonesia, ripe tempeh (two or more days old) is considered a delicacy.

Nutrition

The soy protein in tempeh becomes more digestible as a result of the fermentation process. In particular, the oligosaccharides that are associated with gas and indigestion are greatly reduced by the Rhizopus culture. In traditional tempeh making shops, the starter culture often contains other beneficial bacteria that produce vitamins (like vitamin B12). In western countries, it is more common to use a pure culture containing only Rhizopus oligosporus.

See Soy Health

Preparation

In the kitchen, tempeh is often prepared by cutting it into pieces, soaking in brine or salty sauce, and then frying. Cooked tempeh can be eaten alone, or used in chili, soups and stews. Tempeh has a complex flavor that has been described as nutty, meaty, and mushroom-like. Tempeh freezes well, and is now available in many western countries in ethnic markets and health food stores.

Tempeh bongkrek

Tempeh bongkrek is a variety of tempeh from Central Java, notably Banyumas regency, that is prepared with coconut. This type of tempeh occasionally gets contaminated with the bacterium Burkholderia cocovenans, and the unwanted organism produces toxins (Bongkrek acid and toxoflavin) from the coconut, besides killing off the Rhizopus fungus due to the antibiotic activity of bongkrek acid.

Fatalities from contaminated tempeh bongkrek were once common in the area where it was produced. Thus, the sale of tempeh bongkrek is prohibited by law nowadays; clandestine manufacture continues however due to the superior culinary value. The problem of contamination is not encountered with bean or grain tempeh, which have a different composition of fatty acids that is not favorable for the growth of B. cocovenans but encourages growth of Rhizopus instead. When bean or grain tempeh has the proper color, texture and smell, it is a very strong indication that the product is safe. Tempeh bongkrek which is yellow is always highly toxic due to toxoflavin, but tempeh bongkrek with a normal coloration may still contain lethal amounts of bongkrek acid.

References

Shurtleff, William, and Akiko Aoyagi. 1979 ^*. The book of tempeh. New York: Colophon Books. ISBN 0060912650.
- This book was instrumental in spreading awareness and appreciation of this soyfood in the west, and is still in print decades after the first edition came out. Shurtleff and Aoyagi also published a book on professional tempeh production, which has since gone out of print.

External links

History of Tempeh
Tempeh — Information about tempeh: how to make tempeh at home, health benefits of tempeh.
Book of Tempeh page — Ten-Speed Press
How to make tempeh at home — In-depth instructions on obtaining a tempeh starter and making tempeh at home. Part of the Soybean Utilization FAQ from UIUC.

Fermented foods | Soy products | Vegetarian cuisine | Indonesian cuisine