Vitamin production by fungi during tempeh fermentation

Many vitamins, such as niacin (B3), riboflavin (B2), pyridoxine (B6), pantothenic acid and thiamine, can be produced by the tempeh fungus R. oligosporus (Nout & Rombouts, 1990 Mugula, 1992 Shurtleff & Aoyagi, 2001 Nout & Kiers, 2005). Rhizopus oryzae, another important fungus frequently found in tempeh products (Samson et al., 1987), has also been reported to produce niacin, vitamin K, ergosterol, and tocopherol, pyridoxine, riboflavin and biotin (Mugula, 1992 Wiesel et al., 1997). The...

Effects of yeasts on tempeh fermentation

Yeasts are considered to be the oldest domesticated microorganisms, and have been used to produce alcoholic beverages and leaven bread dough for millennia (Walker, 1999). Certain yeasts have probiotic potential (van der Aa Kuhle et al., 2005), prevent the growth of moulds in storage (Druvefors, 2004), inhibit the production of mycotoxins (Petersson et al., 1998), or bind mycotoxins to the cell wall and consequently reduce the risk of occurrence of mycotoxins in foods (Yiannikouris et al., 2003...

Realtime PCR quantification

Value Amplification Efficiency Graph

In real-time PCR, PCR amplification is linked to a detection process of the PCR products. Thus, amplification and product detection are performed at the same time, which makes it possible to follow the reaction kinetics. Several PCR products detection methods have been developed, including labelled oligonucleotide probes oligoprobes and fluorescent dyes that bind to dsDNA and enhance their fluorescence while binding Mackay, 2004 . Real-time PCR quantification has been used to detect and...

Origin of tempeh

Tempeh, also called 'tempe kedele' in Indonesia, is traditionally made from soybeans Steinkraus et al., 1983 . Tempeh originated in central and east Java Indonesia at the beginning of the 18th century, and is now Indonesia's most popular soy-protein food Astuti et al., 2000 . Tempeh-like products have also been produced in China, such as soybean koji Shurtleff amp Aoyagi, 2001 or Douchi Li-Te et al., 2003 Li-Te et al., 2004 . Douchi Fig.1 is made from black or yellow beans fermented by Mucor...

Potential human health risks of tempeh

No cases of food poisoning have ever been reported after consuming tempeh Ko Swan amp Hesseltine, 1979 . However, there is still a risk due to the potential growth of moulds and pathogenic bacteria Table 2 , and the production of mycotoxins and bacterial toxins. Pathogenic bacteria do not grow well in acidified substrates and even if they can grow, they are normally controlled by LAB Table 2 . The only bacterial toxin reported in tempeh hitherto is produced by Pseudomonas cocovenenans in tempeh...

Aims of this thesis

Soybean tempeh fermentation has been extensively documented Steinkraus et al., 1983 Nout amp Rombouts, 1990 Nout amp Kiers, 2005 , but considerably less is known about barley tempeh. For instance, in soybean tempeh it was found that the presence of other microorganisms such as yeasts and lactic acid bacteria LAB could enhance the nutritional value and hygienic safety of soybean tempeh fermented by R. oligosporus Suparmo, 1989 Ashenafi amp Busse, 1991b Nout, 1995 Wiesel et al., 1997 . In this...

Microbial food fermentation and world food supply

According to the USA Census Bureau's world population clock, the world population is 6.5 billion in 2006, and will reach 9 billion people in the year 2050. An increased food supply is needed to feed this growing population. To meet the demand, legumes, cereal grains and even some agricultural residues that are presently fed to animals and recovered in the form of milk, eggs, broilers, pork and beef, must be converted to human food. In terms of protein generation, meat production on average...

Effects of inoculum concentration of R oligosporus on tempeh fermentation

The inoculation levels of R. oligosporus strongly influenced tempeh fermentation. When R. oligosporus was inoculated at approximately 104 spores g moist substrate, a barley tempeh cake with dense mycelial growth was obtained after 20 h IV . With inoculation at approximately 102 spores g moist barley, the fungus grew more slowly and a barley tempeh cake with dense mycelial growth was not obtained until after 28 to 32 h IV . This slow growth may increase the risk of contamination with pathogens....

Effects of lactic acid bacteria on tempeh fermentation

Fermentation Tempeh Process

There are no reports of food poisoning caused by consuming traditional soybean tempeh Ko Swan amp Hesseltine, 1979 . Nout amp Rombouts 1990 suggested that this safety is due to 1 inherent properties of Rhizopus spp., 2 presence of lactic acid bacteria LAB , 3 incubation under micro-aerobic conditions, and 4 the customary heating prior to consumption. Table 2. Growth of potential pathogenic bacteria and their inhibition by lactic acid bacteria LAB during tempeh fermentation Growth of pathogenic...

Foods made from tempeh

Meat Fermentation Process

Soybean tempeh can be sold fresh, refrigerated Fig. 5 , frozen or even distributed in cans. This fermented product is remarkably versatile and can be served in hundreds of different Western or Asian-style recipes, such as tempeh burgers and sushi Fig. 6 tempeh, lettuce and tomato sandwiches tempeh chops topped with apple sauce crisp slices or cubes added to salads, soups, pizza toppings, stir-fried rice, casseroles, sauces or tacos. The most popular and simplest way of serving is shallow-fried...

The tempeh fungus Rhizopus oligosporus

Rhizopus Oligosporus

Tempeh has been produced in Indonesia for many centuries. However, it was the Dutch scientist Prinsen Geerligs, who in 1895 identified the tempeh mould for the first time Shurtleff amp Aoyagi, 2001 . Many different moulds are found in tempeh, but species within the zygomycete genus Rhizopus dominate Steinkraus et al., 1983 . Rhizopus Mucorales, Mucoraceae, Zygomycota includes three species groups R. oryzae group, R. stolonifer group, and R. microsporus group Schipper amp Stalpers, 1984 , with...

Barley for tempeh production

Barley is the second most abundant cereal grain after wheat grown in Northern Europe. In Sweden, the average yearly production was about 1.7 million tons during the period 1993 to 2005. This was used in the following way 62.3 for animal feeds, 9.9 for beer production and 0.5 for direct human consumption, with the remainder being exported Euro Stat data, supplied by Christina Wikberger, Swedish Board of Agriculture, Statistics Division . Thus, only 10.4 of barley is used for human consumption in...

Barley tempeh production

Barley tempeh has been fermented through a process similar to soybean tempeh Hesseltine et al., 1963 Hesseltine et al., 1967 . It was found that Rhizopus spp. with highly active proteolytic and lipolytic enzymes, but little or no amylase activity, were suitable for producing tempeh from cereal grains wheat, barley, oat, rye and rice . This early attempt to produce barley tempeh used dehulled and cracked barley Hesseltine et al., 1967 . However, commercial barley tempeh has not yet been...

Substrates used for tempeh production

Tempeh Production

Traditionally, tempeh was made from soybean. Yellow-seeded soybeans are usually preferred as raw material Sharma amp Sarbhoy, 1984 , but many different substrates can be used to produce tempeh Table 1 . Some substrates can only be processed to obtain high quality tempeh by combining them with soybeans Wang et al., 1968 Mugula, 1992 Shurtleff amp Aoyagi, 2001 or can only be used to produce protein-rich tempeh flour Cuevas-Rodriguez et al., 2004 . To my knowledge, most of the substrates listed in...

The basic process of tempeh production

Although different substrates can be used to produce tempeh, the basic fermentation process is similar for all substrates. It includes soaking, dehulling if necessary , boiling and fermenting. The main differences between different substrates used in tempeh fermentation are the selection of optimal pre-treatments e.g. when cereals are used it is sometimes necessary to modify the surface of the grain by cutting, cracking or pearling to obtain good growth of the mold , optimal soaking, boiling...