All about the little microbes: Tempeh Fungus starter

What is tempeh?
Tempeh is a popular fermented food in Indonesia and Malaysia which is rich in nutrients and active substances. In my country, it’s one of the common foods that found in Malay’s restaurant and hawker center.

The first time I tasted it, I felt bit uncomfortable because of its odor smell. Actually, high quality tempeh has a mild “mushroomy” or “yeasty” aroma, can be sliced or cubed easily without crumbling. But, when I start to understand some significance of soybean fermentation in tempeh on the vitamins, amino acids, nutritional quality, functional types of microbes, and physico-chemical properties, I begin to love it.

The flavor of soy tempeh is full-bodied. It can be a “star” in any kitchen because it cooks quickly and can be prepared in hundreds of ways, using all cooking methods.

Recently, the consumption of Tempeh has been increasing rapidly, not only in Malaysia and Indonesia but also in the United States and Europe. Although Tempeh is not likely to be exported, the product is consumed and produced in many countries.

The making of tempeh
Tempeh is a fermented product made from soybeans that have been soaked and cooked to soften them. Like sour dough bread, tempeh requires a microbes inoculum starter, which is added to the cooked beans.
This mixture is left for 24 hours and the result is a firm textured product with a somewhat nutty flavor and a texture similar to a chew mushroom. Because Tempeh is firm and it can be formed into a patty, it is used as a substitute for animal products in what in the West is typically called as "mock" burgers or sandwiches.
This soya product is especially popular in Indonesia and is considered a national specialty. It has the necessary characteristics of a dietary staple in that is high in protein and fiber and is rich in other nutrients. It also has the advantage of containing Vitamin B-12, which is a by-product of the fermentation process . In this heat paper the research work carried out on tempeh fermentation and tempeh based products is reviewed.

Role of Microorganisms in Tempeh Production:
The type of microorganisms involved in tempeh production has been reported by many researcher. Tempeh is the result of mixed culture fermentation by a diverse group of microorganisms including moulds, yeasts, lactic acid bacteria and different gram-negative bacteria. Rhizopus oligosporus is the dominant tempeh fungus although some other moulds, such as R. oryzae and Mucor spp, may also contribute to the flavour, texture or nutritive value.

A researcher named Heseltine isolated many fungi from different lots of tempeh made in Indonesia and found that only Rhizophus could make tempeh in pure culture fermentation. They also found that the 40 strains of Rhizophus studied, 25 of them are R.oligosporus others are R.stolonifier，R.arrhizus.R.oryzae, R.formosaensis and.This finding was also confirmed by another researcher Saono , who isolated 118 cultures from 81 tempeh samples collected from markets in various parts of Indonesia. Mulyowidarso et al also reported variable growth of bacteria during fermentation of soybeans into tempeh with R.oligosporus.

There is also another study reported that Klebsiella pneumonia was responsible for the production of vitamin B12 in commercial tempeh. Yeasts are frequently detected in tempeh, but their role is still unknown
Rhizopus moulds produce natural, heat stable antibiotic agents against some disease-causing organisms. Indonesians who eat tempeh as a regular part of their diet recognize it as a medicine for dysentery and rarely fall victim to the intestinal diseases to which they are constantly exposed.

My experiment of making tempeh

: Soak the soybeans water for 1whole night.

1) Put the beans in a cooking pot and add enough water to cover them. Cook for 30 min. Drain off the water and dry the soybeans by continue heating them in the pot on medium heat for a few minutes and until the beans are dry. Allow the soybeans to cool down to below 35°C.

: Inoculating the soybeans with tempeh starter

2) Sprinkle the soybeans with 1 teaspoon of tempeh starter. Mix with a clean spoon for about 1 minute to distribute the tempeh starter evenly. It's very important to mix the tempeh starter very well: it reduces the risk for spoilage and the fermentation will be faster.

3) Perforate plastic cover with holes at a distance of about 1 cm by a thick but sharp needle. A normal needle is too thin, you need a fat needle or small nail (about 0.6 mm in diameter). This will allow the mould to breathe. Divide the soybeans in the two bags and seal them. Press them flat, making sure that the total thickness of the beans is max 3 cm.