TOFU AND SOYMILK PRODUCTION

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					TOFU AND SOYMILK
PRODUCTION
Introduction
Tofu and soymilk are both products made from soya bean, which is a protein-rich grain
legume or pulse. Soya beans (Glycine max) have a high nutritional value and provide a
satisfactory alternative to animal products. They contain good quality protein, oil, vitamins
(from the B-group) and minerals (iron and calcium). Soya milk is an emulsion that is made
by grinding the beans with water and extracting the protein. Tofu is made in a similar way to
cheese, by curdling the milk to extract the protein. Similar vegetable milks and extracted
curds can be made from other legumes including cowpea (Vigna unguiculata), bambara
groundnut (Vigna subterranea) and pigeon pea (Cajanus cajun).

Soymilk is easily digestible and one pint of it can provide over one half of a young child’s daily
protein requirement. It can be sweetened with sugar or flavoured with chocolate, cinnamon
or vanilla. Salt may also be added if desired.

The production of tofu consists of two main steps:
• the preparation of soymilk
• the coagulation of soymilk to form curds which are pressed to form tofu cakes.


Principles of processing and preservation
Traditional soymilk, which is a stable emulsion of oil, water and protein, is simply an aqueous
extract of whole soybeans. The liquid is produced by soaking dry soybeans, and grinding
them with water. Soymilk contains about the same proportion of protein as cow's milk~
around 3.5%; also 2% fat, 2.9% carbohydrate and 0.5% ash. Soymilk can be made at home
with traditional kitchen tools.

Tofu is the extracted protein (curds) of soymilk. It is made by adding acid to the milk which
causes it to curdle. The solid curds (tofu) are pressed to remove all the liquid. Tofu can be
used in a number of different dishes.

Preparation of soymilk

Soaking the soya beans
Soak the soya beans in cold water overnight or in very hot water for 2 to 3 hours, using 3 to 4
cups of water for each cup of dry soya beans. When the beans split open easily and are flat
on the inside, they are ready to be drained. Discard the soaking water and wash the beans
well in clean water.

Grinding and cooking the soya beans
Grind the soaked beans using a grinding rock, hand mill or meat grinder. Add boiling water
to the ground beans (for each cup of dry soya beans use about 8-10 cups of cooking water)
and mix well to make a pulp. Bring the pulp to a boil and continue to heat it for 20 minutes.
Stir regularly to prevent burning. The fresh extracted pulp has a beany flavour and odour,
which can give the milk an unpleasant flavour. It also contains a compound that prevents the
digestion of protein in the body, which reduces the nutritional value of the fresh pulp. It is
important to boil the pulp as this improves both the flavour and nutritional value of the
product. After boiling, remove any scum and insoluble material that floats to the surface of
the milk
Tofu & soymilk production                                                             Practical Action


Straining the soymilk
Use a filter cloth to strain the cooked milk and extract the soymilk from the pulp. Place the
cloth in a sieve which is positioned over a pot. The filter cloth should be made from nylon or
porous material - either a flour or sugar bag can be used. Hold the sides of the cloth in each
hand and move up and down to roll the pulp back and forth so it forms a ball. Twist the cloth
tightly, hold it over a clean container and press gently to extract the milk.




Preparation of tofu
Tofu is made by
coagulating the protein in
soymilk and extracting it in
a solid form.




                               Figure 1: Preparation of tofu from soymilk


Coagulating soymilk
Heat the soymilk (1 litre) over a fire and boil for 3 to 5 minutes with continuous stirring. Remove
the pot from the heat and add 2 tablespoons (30ml) of a 4% acetic acid solution (vinegar). Stir
continuously until the milk starts to coagulate.

Straining the curds and pressing
When large white curds can be seen floating in a clear yellow liquid, called whey, the soymilk is
completely curdled and ready to be filtered through a clean cloth into a suitable mould. The
same method is used here as used in straining the soymilk. Make sure that the filter cloth is
sterilised before use. Do this by boiling it in clean water for 10 minutes prior to use.

To form a block of tofu, cover the top of the tofu with the filter cloth and place a weight on top.
Apply constant pressure for about 20 minutes to squeeze out the excess water. The water
content will reduce by approximately 60%. The pressed tofu can be sliced and fried or eaten
plain with salt. Alternatively, the loose curds can be scrambled in a pan with onion, tomatoes
and salt and served on bread.

Preservation of soymilk and tofu
Soymilk can be stored in a bottle placed in a container of cold water. However, even in cool
weather, soymilk can only be kept for a day using this method. Unseasoned block tofu should
be stored under water to prevent drying out and can be kept for 2 days in moderate
temperatures. When refrigeration is available, soymilk can be kept for up to 5 days and tofu for
about 10 days.

Soymilk that sours will form into curds by natural fermentation. Providing the curds are solid and
not discoloured or slimy, they can be boiled for 30 to 40 minutes to kill the bacteria and made
into cheese. Tofu that becomes slightly sour can also be eaten if boiled for 20 to 30 minutes.




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Tofu & soymilk production                                                               Practical Action


References & useful contacts

•   Tofu and Soymilk Production, Shurtleff, W. & Aoyagi, A. (1984), Lafayette, California, USA
•   Small-scale and Home Processing of Soya Beans with Applications and Recipes, Loo, T.G.
•   Soya - Agrodok 10, Agromisa, The Netherlands. (http://www.agromisa.org/)
•   Soy Demonstration Program, Plenty International (http://www.plenty.org/)
•   Traditional Beancurd Manufacture. Natasha J Johnson (1994), Practical Action, UK
    (www.practicalaction.org)

    •    ATTRA - National Sustainable Agriculture Information Service
         http://attra.ncat.org/attra-pub/soyfoods.html
         Cultivation, harvesting and processing
    •    Soy Info Center
         http://www.soyinfocenter.com
         Information about soyfoods and utilization of soybeans in both printed and electronic
         database formats.
    •    ProSoya Inc.
         http://www.prosoya.com/
         A useful website that explains how to make soymilk and tofu. Answers lots of frequently
         asked questions.
    •    Soya Dairy – Independent Consultants
         http://www.soyadairy.com/index.html
         Information on soya drinks and beverages, soy yogurt, soymilk powder, soya dairy foods

Equipment suppliers
Note: this is a selective list of suppliers and does not imply endorsement by Practical Action

Specific soybean and soymilk machinery

Central Institute of Agricultural Engineering
Nabi Bagh
Berasia Road
Bhopal - 462 038 (M.P.)
India
Tel: +91 755 2737191
Fax: +91 755 2734016
E-mail: ciae@x400.nicgw.nic.in
Web: http://www.ciae.nic.in/
• Soybean Dehuller. Capacity: 100kg/hour
• Low-cost multipurpose grain mill. Suitable for soybean Capacity: 10-70 kg/hour
• Soybean flaking machine. Capacity: 20 kg/hour

Lehman Hardware and Appliances Inc.
P.O. Box 41
Kidron
Ohio 44636
USA
Tel orders: +1 877 438 5346
Tel enquiries: +1 888 438 5346
E-mail: info@lehmans.com
Website: http://www.lehmans.com
•   Small-scale yoghurt incubator: Works with any milk including cow, soybean or goat milk.




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Tofu & soymilk production                                                          Practical Action

Actini SA
Parc de Montigny
Maxilly
75500 Evian
France
Tel: +33 (0)4 50 83 12 12
Fax: +33 (0)4 50 83 12 10
E-mail: actini@actini.com
Web: http://www.actini.com/gb/documentation/ACTINI-Soymilk-production-line.pdf
    •    An automated platform for soya milk production. “Milk” can be produced from;
        groundnut, almond, hazelnut, lupin, horse bean and cereals such as rice and oats.

Grinding mills and liquidisers
                                                     Alvan Blanch
C S Bell Co                                          Chelworth
170 West Davis Street                                Malmesbury
PO Box 291                                           Wiltshire
Tiffin, Ohio 44883                                   SN16 9SG
USA                                                  United Kingdom
Tel: +1 419 448 0791                                 Tel: +44 1666 577333
Fax: +1 419 448 1203                                 Fax: +44 1666 577339
E-mail: sales@csbell.co.com                          Email: enquiries@alvanblanch.co.uk
Website: http://www.csbellco.com/                    Web: www.alvanblanch.co.uk




Howtopedia – The Appropriate Technology wiki
http://www.howtopedia.org/en/How_to_make_Tofu_and_Soyamilk




     Practical Action
     The Schumacher Centre for Technology and Development
     Bourton-on-Dunsmore
     Rugby, Warwickshire, CV23 9QZ
     United Kingdom
     Tel: +44 (0)1926 634400
     Fax: +44 (0)1926 634401
     E-mail: inforserv@practicalaction.org.uk
     Website: http://www.practicalaction.org/

     This document was produced by Dr. S Azam Ali for Practical Action in March
     2008. Dr. S Azam-Ali is a consultant in food processing and nutrition with over 15
     years experience of working with small-scale processors in developing
     countries.




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Description: A 90 grams of tofu contains only 50 kcal, eat less meat and tofu, maintain protein intake at the same time, good for weight loss. In addition, the tofu is considered ideal for yoga practice with food.