ORIENTAL FERMENTED FOODS

MOLD MODIFIED FOODS

Reason for studying oriental fermented foods:

Different from western foods interms of taste, texture, flavor and appearance.

Different from western foods interms of microbiological standpoint: mixed culture of yeast, bacteria, and mold.

Since it is cheap and nutritious, large number of people consume.

There are too many things to modernize plants.

Oriental foods are receiving increasing attention of western consumers. hİghly nutritive because;

Complementary effect of proteins from plant and animal sources

İncreased protein efficiency ratio and digestibility

Synthesis of vitamins

Shorter cooking time

Desirable enzymes are produced

The lipoxygenase enzyme is responsible for the “beany” flavor commonly noted in soymilk. The

reaction catalyzed by the enzyme involves water, the unsaturated oil, and oxygen and the end-

product hexanal is one of the compounds responsible for the beany flavor.

Soy sauce

-dark -brown liquid with a salty taste and district pleasent aroma

– made by fermenting soybean, wheat and salt with a mixture of mold , yeast, and bacteria.

-During fermentation

Proteins …. peptidies, aminoacids, sugar alcohols, acids

carbohydrates are also hydrolysed

chemical hydrolysis is tried in U.S.A but taste of product is not the same

soy sauce is used as a seasoning agent in preparation of food

Japan leads the soy sauce industry in the world

Shoyu’ is the Japanese name for soy sauce.

In Japan the total production is about 1.04 million kiloliters (kl),

The annual consumption of shoyu per capita is about 8.3 l,

The consumption volume in Japan is decreasing slightly, but that in American and European area is increasing.

Raw Materials and their treatment

Soy Beans: defatted soybean

Soy bean ® washed ® soaked overnight ® drained ® steamed (at 10lb/ in2 for several hrs)This will

effect the future enzymatic action on soy proteins

Wheat:

Wheat ® roasted ® coarsely crushed. Adds color and flavor to resulting soy sauce and destroys

surface microorganisms and facilitates enzymatic hdrolysis

Reason of using wheat:

The mold grows better and produces more enzymes on a mixture of wheat -soybean than any of them alone

Addition of roasted crushed wheat reduce the growth of undesirable microorganism

Cooked soybean : 60 % moisture good for bacterial growth

Soybean-wheat mixture : 45 % moisture good for mold growth but not bacteria

wheat serves as a precursor of sugar, alcohols, organic acids and flavor compounds.

Wheat is rich in glutamic acid

Salt

NaCI ® gives salty taste, surpress undesirable organisms

Soy sauce koji:

Koji: is a japanese name gives to a preparation consisting of mold growth on cooked cereals or/and soybeans.

– serves as an enzyme source.(like malt in alcoholic fermentations)

Soy sauce koji is made from a mixture of roasted wheat and steamed soybeans with

A koji starter ® Aspergillus oryzae or A. soyae (Called tane koji)

Aspergillus oryzae

Aspergillus oryzae on wheat

Preparation of tane koji:

Polished rice is soaked in water overnight ® drained ® steamed for 1 hr ® mixed with 2% of wood ash, for trace elements ® inoculate with A. oryzae spores ® Spread out in tray 1,5 cm ® cover with damp clothes ® incubate at 30C for 5 days (green to yellowish spores of A. oryzae mycellium ® spores are harvested ® dried at 50 C and stored at 15 C. [ 25×107 viable spore/gm of tane koji]

A good soy sauce has 18% salt, 4.6-4.8 final pH

Price is determined by:

Nitrogen yield

Total soluble nitrogen

Amino nitrogen/total soluble nitrogen ® ratio (>50% is good)

Glutamic acid and salt are principle flavoring constituents

Sugars present are glucose, arabinose, xylose, maltose, galactose, glycerol and mannitol (also alcohols)

Organic acids: lactic, succinic and pyroglutamic

Color is due to non-enzymatic browning

SAFETY OF ORIENAL FERMENTED FOODS

Scientist can not find aflatoxin and aflatoxin producing cultures in oriental fermented foods unless they intentionally contaminate with these cultures.

Processing procedures such as cooking, salting, acid formation, antibiotics production, and low moisture are the probable reasons for the safety of oriental fermented foods.

Mycotoxins – the yellowish colonies are of Aspergillus flavus, a producer of aflatoxin.  The green colonies are of  Penicillium, another mycotoxin-producing genus (ochratoxin, patulin, penitrem, PR toxin).

TEMPEH

“Tempeh” is a fermented soybean product and meat substitute that originated in Indonesia.

It is probably the first “fast food” in that it can be deep-fried in 3–4 min or cooked in 10 min.

In the first step the soybeans are soaked in water or acidified water at room temperature.

During this stage a partial germination of the soybeans may occur depending on the amount of O2 available to the seed, and acid is produced by bacteria growing in the soak water.

Depending on the temperature during soaking, bacteria reach 108–1010 colony-forming units per ml after 24–36 h.

The pH drops from 6.5 to 4.5 due to the growth of the acid-producing bacterial species – e.g., Lactobacillus casei, Streptococcus faecium, Staphylococcus epidermidis, and Klebsiella pneumoniae that are present naturally on the soybeans.

The acid helps to prevent the growth of undesirable microorganisms, but any partial seed germination can affect the protein properties of the soybean and the subsequent fungal growth phase.

The bacteria that grow in the steeping water produce vitamin B12, a significant nutrient in tempeh.

The most desirable bacterial species for this stage is K. pneumoniae, but other pure bacterial starter cultures can perform the same function.

The soaked beans are de-hulled and carefully cooked to avoid overcooking or undercooking of the beans.

The soybeans are then drained, cooled below 35 °C, and dusted with wheat flour to provide a good source of fermentable carbohydrate, and inoculated.

The desirable fungal species for successful tempeh production, whether arising from environmental inoculation or from pure starter inoculation, are Rhizopus oligosporus

Tempeh must be consumed fairly quickly.

Defects include:

(1) black patches due to fungal sporulation,

(2) slime due to excessive bacterial growth because of too little O2 or a temperature of 42 °C,

(3) a yellow color due to growth of toxic fungi.

The yellow color indicates that the tempeh is highly toxic and it should not be eaten.

During the fungal growth phase the O2 level must be controlled at a reduced level, otherwise the fungus will grow too quickly and form black spore masses that degrade the quality of the tempeh.

The traditional way to control O2 is to wrap the inoculated beans in banana leaves, but a modern innovation is the use of microperforated polyethylene plastic.

The fungus grows and mycelia knit the beans into a firm cake to give the characteristic meaty texture.

The enzymes from the fungi transform the soybeans making them more nutritious by hydrolyzing the protein and complex carbohydrates and increasing the levels of the vitamins – riboflavin, niacin, pantothenic acid, and vitamin B6.

MISO (Bean paste)

Most popular fermented soybean good in Japan.

Fermentation principles similar to soy sauce.

Miso: like peanut butter (smooth, some chruncy) light-yellow to reddish-brown.

Bean paste (miso) is used as flavoring agent.

Freeze dried miso is getting common in western countries.

® use in dips, salad dressing, sauces

contains > 10% salt. So can be kept for a while without refrigeration

TOFU

Soy cheeses (soya cheeses) are a curd made from soymilk (soybean milk), called tofu in English.

Tofu is made in a similar process to making cheese from milk.

The soymilk is curdled by adding coagulants (CaSO4, MgCl2, glucono-delta- lacton (GDL)).

Curds are then pressed into cakes of various types.

Soft tofu is not pressed and is eaten as it is.

Medium-soft tofu is the most popular in everyday use.

Firm tofu is used in processed foods which are fried, grilled, fermented, and dried.

SUFU

Sufu is mostly sold in the west, more common under the name, Preserved Bean-curd.

sufu virtually means spoiled tofu, due to the strong flavour and pungent aroma.

Sufu resembles the dairy equivalent in cheese, Parmesan or Camembert and is sometimes referred to as Chinese cheese.

Sufu may satisfy cravings for cheese for individuals following a vegan diet.

Salting does five things:

it imparts a salty taste to the sufu,

it prevents the growth of undesirable organisms,

it stops the growth of the mold,

it releases the proteolytic enzymes bound to the mold mycelia so they can penetrate into the tofu to transform it, removes some water from the tofu blocks.

Salting can be by dry salting or brine salting.

Dry salting: takes longer, does not result in a consistent product(6–12 days),16%, washed with water.

Brining is done with a saturated salt solution, or an alcoholic brine solution in which the blocks are immersed for 4–5 days, resulting in final moisture levels of 50–65% with 12% salt.

The ethanol has two effects: first, during ripening lipolytic enzymes release free fatty acids that combine with ethanol to produce aromatic esters,

it seems to interfere with protein degradation when compared with salted sufu.

Ang-kak

Chineese originated food colorant

Washed and sterilized rice is inoculated with Monascus purpureus

In 3 days begin to redden and 3 weeks color will turn to deep purplish red

Dry at 40 C

Pigments, monoscoribrin and monoscoflavin will accumulate in the m.o. solubilise reacting it with water soluble proteins

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