Tofu is a food
first recorded in China 2000 years ago.
It spread from China to many other Asian countries and lately to most
Western countries.
Nutritional
content of tofu. The
various sources I have looked vary dramatically. The results I have quoted are
only one possibility. All the sites say
the following: tofu contains very few calories; contains large amounts
of protin; contains all the
essential amino acids your body needs; most of the fat is unsaturated. The minerals it contains can vary depending
on the coagulant used in manufacture but generally there is a lot of calcium
(130 mg; 13%) and iron (1.1 mg; 8%).
Tofu also
contains isoflavones. The main ones function
as phytoestrogen. They function in the body as estrogen. Basically tofu contains soy isoflavones which
act like estrogen.
Tofu contains
anti-nutrients such as trypsin inhibitors, phytates and lectins. They interfere
with the absorption and digestion of nutrients. Fermentation reduces the
anti-nutrients.
100gm Tofu
291 kJ (70 kcal)
1.5 gm
carbohydrates (1%)
4.8 gm fat (7%)
Dietary fiber
0.3gm (1%)
Protein 8 gm
(16%)
Tofu is made from
soy milk. Soya beans are soaked, ground, boiled and strained to make soy milk.
The soy milk is then coagulated. Coagulation means turning the protein and oil
suspension in the soy milk into a solid and a liquid. The mixture should
resemble curds and whey. The thin watery liquid is strained from the solid
particles. There are many different
coagulants that can be used to turn soy milk into curds and whey.
- · Calcium sulfate (gypsum): traditional in China. Resultant tofu is high in calcium. No taste.
- · Magnesium chloride and calcium chloride: Tofu is smooth and tender. No taste. Common in Western countries. Called Nigari.
- · Naturally occurring edible acids: Glucono delta-lactone, acetic acid, citric acid can affect the taste, create a soft smooth tofu.
- · Enzyme such as papain or proteases from microorganisms.
- · More than one coagulant can be used at once.
The amount of water extracted from the tofu curds determines the texture of
the final tofu. If the curds
are lightly pressed and lightly strained soft tofu is the result. Soft tofu contains the largest amount of
water. Firmer tofu bounces back when pressed and more closely resembles meat.
The drier forms of tofu can be processed, pickled or dried further.
Other liquids can be coagulated to produce something similar to tofu. “Tofu”
has been made from almond milk, coconut milk, mango juice, eggs, sesame seeds
or peanuts. Basically if a liquid contains a suspension it is possible to turn
the suspension into a solid.
Tofu versus
meat
In Australia tofu
is generally considered a healthy alternative to meat.
Is the protein in
tofu better for you than protein in meat? No it is the same amino acids. Meat
may be tougher or chewier. That is because meat contains gristle and tendons. Not
because the protein is different.
How does the
nutrition content of tofu compare with animal meat? Is it healthier than meat?
100gm of meat will contain 0 carbs, 20 gm fat, 290 calories, 0 fiber and the protein equivalent to 50 gm of tofu.
Animal meat contains more protein. The fat in meat is
largely unhealthy saturated fat. Tofu largely
contains healthy fat but a lot depends on how you cook the tofu. Tofu absorbs
liquids and if deep fried can contain more fat than meat. If you want the
cardiovascular benefits of tofu (lower total cholesterol, lower LDL) then
remember tofu readily absorbs the cooking oil.
What is the ethical
difference between animal meat and tofu? Growing soya beans versus killing
animals. Tofu wins.
Is tofu
environmentally sounder than meat? Growing soya beans versus growing pasture or
a crop and then feeding it to cattle.
Tofu wins.
Cooking
In Asian cooking,
tofu can be eaten raw, boiled, steamed or stir-fried. It can be cooked in a
soup, cooked in a sauce, or stuffed with fillings. The idea of using tofu as a
meat substitute is not common in Asia.
In Western cooking (anything except traditional Asian cooking) the firm
tofu is often used as a meat substitute and grilled, fried, boiled or
roasted. The softer types are used in
desserts, soups, shakes and sauces. Tofu is bland and takes up any
flavor available. If grilled or fried
then it can be marinated first. Softer tofu can be used as a cheese
replacement. In any recipe you can replace the cheese with soft tofu. Tofu can
be used in Indian-style curries replacing the paneer cheese.
Health and Nutrient
Benefits
According to some work, replacing meat and dairy with tofu
leads to an increased intake of folate, vitamin K, calcium, magnesium, iron,
fiber and will lower intake of cholesterol and saturated fat.
Cardiovascular Benefits of Tofu
Fermented soy foods contain peptides that have anti-oxidant and
anti-inflammatory properties and blood pressure lowering properties.
The main effect of soy intake is the lowering of LDL
cholesterol. Raising of the HDL is less likely.
Soy isoflavones can decrease blood vessel inflammation and
improve their elasticity
Tofu also
contains saponins which are known to improve blood cholesterol.
The theory says
tofu is better than meat for cardiovascular health.
Cancer Prevention Benefits
In the lab soy isoflavones (genistein) has been shown to
suppress cancer cells. The medical profession is divided. Some say genistein
helps protect against breast, ovarian, endometrial and prostate cancers. Some say large amounts of dietary soy promote
hormone related cancers (breast and prostate).
What do the
clinical studies show? Many show consumption of soy products and decreased
incidence of breast cancer. Many clinical studies have shown no increased risk
of breast cancer (even in post-menopausal women).
Cancer of the
digestive system. Increased intake of tofu has been linked with less cancer.
Tofu and
Prostate Cancer. Increased consumption of soy has been linked to lower risk of
prostate cancer.
Obesity Benefits
Tofu contains peptides involved in obesity prevention and
treatment. They lead to less fat cells in the body. Fermented tofu contains
more of these favorable peptides.
One study showed intake of soy isoflavones resulted in weight
loss.
Diabetic
benefits
Studies have
shown soy isoflavones have good effects on blood sugar levels and insulin
activity.
Animal studies
also have shown soy foods lead to improved insulin
activity and less
risk of diabetes.
You cannot say
tofu prevents diabetes but you can say tofu doesn’t cause diabetes and may be
more beneficial than harmful.
Bone
health Studies suggest ingestion of soy isoflavones
reduces bone loss.
Brain function Soy
isoflavones may be good for brain memory and brain function.
Skin Soy isoflavones may decrease wrinkles and
improve skin elasticity.
Potential
medical problems
Certain doctors
have advised certain people to avoid soy products. Doctors have been concerned
about the following medical states:
Kidney or
gallbladder stones. Tofu contains oxalates.
Breast tumors.
Tofu has weak hormonal effects.
Thyroid
disease. Tofu contains goitrogen.
Children. Soy isoflavones may interfere with the development
of reproductive organs.
