| CORN and Corn Oil nutrition values, health benefits and side effects zhion@zhion.com August 2011 |
INTRODUCTION
Corn has been an important nutritional resource for thousands of years because of its high
protein and carbohydrate content. Corn can be traced back to Mexican or central American
cultures as early as 3400 B.C., and has become a staple among Native American
civilizations throughout the Western Hemisphere. Today, corn has less starch and is sweeter.
The sweetness accounts for its popularity among Americans. Its oil has good sensory
qualities for use in salad preparation and cooking. [1]
Varieties There are more than two hundred varieties of corn. All are good sources of vitamin
C, but only yellow kernels contain small amounts of vitamin A in the form of beta carotene.
Selection Make sure the husks are green, tight and fresh looking. Pull the husk open to make
sure that the ear contains tightly packed rows of plump kernels. The kernels should be smaller
at the tip of each ear. Large kernels at the tip is a sign of overmaturity. If you pinch a kernel,
milky juice should spurt out. Corn should be stored in a cool area. Warmth causes the sugar
content of corn to be converted into starch. This process will cause the ears to become less
sweet.
Storage If the corn is not cooked shortly after it is purchased, then it should be stored in
refrigerator. Refrigeration helps the corn retain its sugar and vitamin C content. If you buy
unhusked corn, keep it in its husk until you are ready to cook it. This will help the corn retain its
moisture content. To fully enjoy the great taste of sweet corn, cook it as soon as possible. The
sooner the better is a good "rule of thumb."
Chemical composition of corn
The serving size of 1 medium ear is 90 g. It contains 130 calories, 2 g of total fat, 0 mg of
cholesterol, 25 mg of sodium, 29 g of total carbohydrate, 4 g of dietary fiber, 9 g of sugars
and 5 g of protein. Corn is also a source of anti-oxidants, iron, vitamins A and C.
De Mejia EG and Prisecaru VI from University of Illinois at Urbana-Champaign have pointed
out that corn contains important chemicals called lectins. This unique group of proteins and
glycoproteins attribute various health benefits of corns. Several lectins have been found to
possess anticancer properties in vitro, in vivo, and in human case studies; they are used as
therapeutic agents, preferentially binding to cancer cell membranes or their receptors,
causing cytotoxicity, apoptosis, and inhibition of tumor growth. [9]
What are the health benefits of corns?
Epidemiological studies have shown that consumption of corn and other grain products is
associated with reduced risk of chronic diseases. The health benefits of corn are attributed in
part to their unique phytochemical composition. [4] However, the phytochemical contents in
grains have been commonly underestimated in the literature, because bound phytochemicals
were not included. Liu RH and co-workers from Cornell University investigated the complete
phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their
antioxidant activities in a few uncooked whole grains. They found that corn had the highest
total phenolic content (15.55 micromol of gallic acid equiv/g of grain) of the grains tested,
followed by wheat (7.99 micromol), oats (6.53 micromol), and rice (5.56 micromol). [4]
The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats
and wheat, and 62% in rice). Ferulic acid was the major phenolic compound in grains tested,
with free, soluble-conjugated, and bound ferulic acids present in the ratio 0.1:1:100. Corn had
the highest total antioxidant activity (181.42 micromol of vitamin C equiv/g of grain), followed
by wheat (76.70 micromol), oats (74.67 micromol), and rice (55.77 micromol). Bound
phytochemicals were the major contributors to the total antioxidant activity: 90% in wheat,
87% in corn, 71% in rice, and 58% in oats. Bound phytochemicals could survive stomach and
intestinal digestion to reach the colon. This may partly explain the mechanism of grain
consumption in the prevention of colon cancer, other digestive cancers, breast cancer, and
prostate cancer. [4]
Why does processed sweet corn provide more benefits than raw sweet corn?
Vitamin C in apples has been found to contribute <0.4% of total antioxidant activity, indicating
most of the activity comes from other phytochemicals. This suggests that processed fruits and
vegetables may retain their antioxidant activity despite the loss of vitamin C. Again, Liu RH
and co-workers from Cornell University have shown that thermal processing at 115 degrees
C for 25 min significantly elevated the total antioxidant activity of sweet corn by 44% and
increased phytochemical content such as ferulic acid by 550% and total phenolics by 54%,
although there was a loss of 25% vitamin C. Consequently, processed sweet corn has
increased antioxidant activity equivalent to 210 mg of vitamin C/100 g of corn compared to
the remaining 3.2 mg of vitamin C in the sample that contributed only 1.5% of its total
antioxidant activity. [5]
CORN OIL NUTRITION FACTS
how to make corn oil - corn oil extraction
By removing free fatty acids and phospholipids from the crude corn oil, the refined corn oil
has excellent frying quality and resistance to smoking or discoloration. Because of its
pleasant taste, U.S. manufacturers like to incorporate corn oil in margarines, cooking or salad
oil.
Prior to the civil war, the main sources for starch had been wheat and potatoes. Corn refining
began with the development of the process for corn starch hydrolysis. By 1857, the
corn-starch industry reached significant proportions in the U.S. At that time, corn starch
industry has only one product-starch. Today, products derived from corn starch include corn
syrup, anhydrous sugar, maltodextrin, dextrose, glucose and starch. [8]
Corn oil health benefits, Corn oil nutrition facts and Corn oil ingredients
chemical composition of corn oil
Dupont J and co-workers from Food and Nutrition Science Consulting, CO claimed that
refined corn oil is composed of 99% triacylglycerols with polyunsaturated fatty acid (PUFA)
59%, monounsaturated fatty acid 24%, and saturated fatty acid (SFA) 13%. The
polyunsaturated fatty acid is linoleic acid (C18: 2n-6) primarily, with a small amount of
linolenic acid (C18: 3n-3) giving a n-6/n-3 ratio of 83. Linoleic acid is essential for skin and
cell membrane integrity and icosanoids production. Icosanoids are necessary for
reproductive, cardiovascular, renal, and gastrointestinal functions and resistance to disease.
Corn oil is also a good source of of ubiquinone, alpha- and gamma-tocopherols (vitamin E).
Because the consumption of corn oil can replace saturated fatty acids with polyunsaturated
fatty acids and corn oil contains a large amount of polyunsaturated fatty acids, corn oil has
benefits of cholesterol-lowering effects, in general. [1]
Nalbone G and co-workers in France supplemented rats with a low-fat diet (2.2% lard plus
2.2% corn oil), a corn oil diet (17%), a salmon oil diet (12.5%) plus 4.5% corn oil, or a lard
diet (15%) plus 2% corn oil for eight weeks. All these diets contained 1% cholesterol. They
found that the salmon oil-diet lowered the blood cholesterol (-50%) and triglyceride (-56%)
while the corn oil lowered the triglycerides by 40%. [2]
Ostlund RE Jr and co-workers from The Washington University at St Louis have concluded
that phytosterols comprising less than 1% of commercial corn oil could substantially reduce
cholesterol absorption and this might account for part of the cholesterol-lowering activity of
corn oil from a study of healthy subjects with a mean serum cholesterol level of 5.1 mmol/L.
They found that the cholesterol absorption was 38% higher after consumption of the
sterol-free corn oil than after consumption of commercial corn oil with an identical fatty acid
content in a study of 10 healthy subjects. And, when corn oil phytosterols were added back to
sterol-free corn oil at a concentration of 150 mg/test meal, cholesterol absorption was
reduced by 12% after inclusion of 300 mg phytosterols. [3]
CORN OIL HEALTH - SIDE EFFECTS
According to a study from the University of Hawaii, fast-food chains are more likely than
smaller restaurants to cook their French fries in corn oil, which is higher in cholesterol-raising
saturated fats than other vegetable oils. An article from Bloomberg reports that the fry oil used
now by the chains includes corn oil that is higher in saturated fats, that also raises cholesterol.
[10]
Animal studies have shown that supply of polyunsaturated fatty acid is one of the
requirements for cancer growth. Wu B and co-workers from Saga Medical School, Japan
found that long-term dietary corn oil promotes azoxymethane-induced colon cancer
development partly by inhibiting the tumor suppressor gene p53-mediated
mitochondria-dependent apoptosis in a study of male Sprague-Dawley rats. [6] However, the
amount of polyunsaturated fatty acid required for cancer growth is considered to be larger
than that needed of the host. Thus, excessive intake of corn oil is not recommended. [1] In
addition, Chen F and co-workers from University of Miami observed that a significant positive
relation was found between mortality rate and the consumption of dietary corn and wheat flour
in a study of esophageal cancer cases in Shanxi Province, China. [7]
REFERENCE [1] Food uses and health effects of corn oil. J Am Coll Nutr. 1990 Oct;9(5):438-70. [2] Effects of fish
oil, corn oil and lard diets on lipid peroxidation status and glutathione peroxidase activities in rat heart. Lipids.
1989 Mar;24(3):179-86. [3] Phytosterols that are naturally present in commercial corn oil significantly reduce
cholesterol absorption in humans. Am J Clin Nutr. 2002 Jun;75(6):1000-4. [4] Adom KK Liu RH Antioxidant activity
of grains. J Agric Food Chem. 2002 Oct 9;50(21):6182-7. [5] Dewanto V et al, Processed sweet corn has higher
antioxidant activity. J Agric Food Chem. 2002 Aug 14;50(17):4959-64. [6] Dietary corn oil promotes colon cancer
by inhibiting mitochondria-dependent apoptosis in azoxymethane-treated rats. Exp Biol Med (Maywood). 2004
Nov;229(10):1017-25. [7] Corn and wheat-flour consumption and mortality from esophageal cancer in Shanxi,
China. Int J Cancer. 1993 Apr 1;53(6):902-6. [8] Corn Oil, Corn Refiners Association, Online Publication,
November 22, 2005. [9] Lectins as bioactive plant proteins: a potential in cancer treatment. Crit Rev Food Sci Nutr.
2005;45(6):425-45. [10] Fast-Food Fries Cooked in Higher-Fat Corn Oil, Study Shows www.bloomberg.com
January 18, 2010
Corn has been an important nutritional resource for thousands of years because of its high
protein and carbohydrate content. Corn can be traced back to Mexican or central American
cultures as early as 3400 B.C., and has become a staple among Native American
civilizations throughout the Western Hemisphere. Today, corn has less starch and is sweeter.
The sweetness accounts for its popularity among Americans. Its oil has good sensory
qualities for use in salad preparation and cooking. [1]
Varieties There are more than two hundred varieties of corn. All are good sources of vitamin
C, but only yellow kernels contain small amounts of vitamin A in the form of beta carotene.
Selection Make sure the husks are green, tight and fresh looking. Pull the husk open to make
sure that the ear contains tightly packed rows of plump kernels. The kernels should be smaller
at the tip of each ear. Large kernels at the tip is a sign of overmaturity. If you pinch a kernel,
milky juice should spurt out. Corn should be stored in a cool area. Warmth causes the sugar
content of corn to be converted into starch. This process will cause the ears to become less
sweet.
Storage If the corn is not cooked shortly after it is purchased, then it should be stored in
refrigerator. Refrigeration helps the corn retain its sugar and vitamin C content. If you buy
unhusked corn, keep it in its husk until you are ready to cook it. This will help the corn retain its
moisture content. To fully enjoy the great taste of sweet corn, cook it as soon as possible. The
sooner the better is a good "rule of thumb."
Chemical composition of corn
The serving size of 1 medium ear is 90 g. It contains 130 calories, 2 g of total fat, 0 mg of
cholesterol, 25 mg of sodium, 29 g of total carbohydrate, 4 g of dietary fiber, 9 g of sugars
and 5 g of protein. Corn is also a source of anti-oxidants, iron, vitamins A and C.
De Mejia EG and Prisecaru VI from University of Illinois at Urbana-Champaign have pointed
out that corn contains important chemicals called lectins. This unique group of proteins and
glycoproteins attribute various health benefits of corns. Several lectins have been found to
possess anticancer properties in vitro, in vivo, and in human case studies; they are used as
therapeutic agents, preferentially binding to cancer cell membranes or their receptors,
causing cytotoxicity, apoptosis, and inhibition of tumor growth. [9]
What are the health benefits of corns?
Epidemiological studies have shown that consumption of corn and other grain products is
associated with reduced risk of chronic diseases. The health benefits of corn are attributed in
part to their unique phytochemical composition. [4] However, the phytochemical contents in
grains have been commonly underestimated in the literature, because bound phytochemicals
were not included. Liu RH and co-workers from Cornell University investigated the complete
phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their
antioxidant activities in a few uncooked whole grains. They found that corn had the highest
total phenolic content (15.55 micromol of gallic acid equiv/g of grain) of the grains tested,
followed by wheat (7.99 micromol), oats (6.53 micromol), and rice (5.56 micromol). [4]
The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats
and wheat, and 62% in rice). Ferulic acid was the major phenolic compound in grains tested,
with free, soluble-conjugated, and bound ferulic acids present in the ratio 0.1:1:100. Corn had
the highest total antioxidant activity (181.42 micromol of vitamin C equiv/g of grain), followed
by wheat (76.70 micromol), oats (74.67 micromol), and rice (55.77 micromol). Bound
phytochemicals were the major contributors to the total antioxidant activity: 90% in wheat,
87% in corn, 71% in rice, and 58% in oats. Bound phytochemicals could survive stomach and
intestinal digestion to reach the colon. This may partly explain the mechanism of grain
consumption in the prevention of colon cancer, other digestive cancers, breast cancer, and
prostate cancer. [4]
Why does processed sweet corn provide more benefits than raw sweet corn?
Vitamin C in apples has been found to contribute <0.4% of total antioxidant activity, indicating
most of the activity comes from other phytochemicals. This suggests that processed fruits and
vegetables may retain their antioxidant activity despite the loss of vitamin C. Again, Liu RH
and co-workers from Cornell University have shown that thermal processing at 115 degrees
C for 25 min significantly elevated the total antioxidant activity of sweet corn by 44% and
increased phytochemical content such as ferulic acid by 550% and total phenolics by 54%,
although there was a loss of 25% vitamin C. Consequently, processed sweet corn has
increased antioxidant activity equivalent to 210 mg of vitamin C/100 g of corn compared to
the remaining 3.2 mg of vitamin C in the sample that contributed only 1.5% of its total
antioxidant activity. [5]
CORN OIL NUTRITION FACTS
how to make corn oil - corn oil extraction
By removing free fatty acids and phospholipids from the crude corn oil, the refined corn oil
has excellent frying quality and resistance to smoking or discoloration. Because of its
pleasant taste, U.S. manufacturers like to incorporate corn oil in margarines, cooking or salad
oil.
Prior to the civil war, the main sources for starch had been wheat and potatoes. Corn refining
began with the development of the process for corn starch hydrolysis. By 1857, the
corn-starch industry reached significant proportions in the U.S. At that time, corn starch
industry has only one product-starch. Today, products derived from corn starch include corn
syrup, anhydrous sugar, maltodextrin, dextrose, glucose and starch. [8]
Corn oil health benefits, Corn oil nutrition facts and Corn oil ingredients
chemical composition of corn oil
Dupont J and co-workers from Food and Nutrition Science Consulting, CO claimed that
refined corn oil is composed of 99% triacylglycerols with polyunsaturated fatty acid (PUFA)
59%, monounsaturated fatty acid 24%, and saturated fatty acid (SFA) 13%. The
polyunsaturated fatty acid is linoleic acid (C18: 2n-6) primarily, with a small amount of
linolenic acid (C18: 3n-3) giving a n-6/n-3 ratio of 83. Linoleic acid is essential for skin and
cell membrane integrity and icosanoids production. Icosanoids are necessary for
reproductive, cardiovascular, renal, and gastrointestinal functions and resistance to disease.
Corn oil is also a good source of of ubiquinone, alpha- and gamma-tocopherols (vitamin E).
Because the consumption of corn oil can replace saturated fatty acids with polyunsaturated
fatty acids and corn oil contains a large amount of polyunsaturated fatty acids, corn oil has
benefits of cholesterol-lowering effects, in general. [1]
Nalbone G and co-workers in France supplemented rats with a low-fat diet (2.2% lard plus
2.2% corn oil), a corn oil diet (17%), a salmon oil diet (12.5%) plus 4.5% corn oil, or a lard
diet (15%) plus 2% corn oil for eight weeks. All these diets contained 1% cholesterol. They
found that the salmon oil-diet lowered the blood cholesterol (-50%) and triglyceride (-56%)
while the corn oil lowered the triglycerides by 40%. [2]
Ostlund RE Jr and co-workers from The Washington University at St Louis have concluded
that phytosterols comprising less than 1% of commercial corn oil could substantially reduce
cholesterol absorption and this might account for part of the cholesterol-lowering activity of
corn oil from a study of healthy subjects with a mean serum cholesterol level of 5.1 mmol/L.
They found that the cholesterol absorption was 38% higher after consumption of the
sterol-free corn oil than after consumption of commercial corn oil with an identical fatty acid
content in a study of 10 healthy subjects. And, when corn oil phytosterols were added back to
sterol-free corn oil at a concentration of 150 mg/test meal, cholesterol absorption was
reduced by 12% after inclusion of 300 mg phytosterols. [3]
CORN OIL HEALTH - SIDE EFFECTS
According to a study from the University of Hawaii, fast-food chains are more likely than
smaller restaurants to cook their French fries in corn oil, which is higher in cholesterol-raising
saturated fats than other vegetable oils. An article from Bloomberg reports that the fry oil used
now by the chains includes corn oil that is higher in saturated fats, that also raises cholesterol.
[10]
Animal studies have shown that supply of polyunsaturated fatty acid is one of the
requirements for cancer growth. Wu B and co-workers from Saga Medical School, Japan
found that long-term dietary corn oil promotes azoxymethane-induced colon cancer
development partly by inhibiting the tumor suppressor gene p53-mediated
mitochondria-dependent apoptosis in a study of male Sprague-Dawley rats. [6] However, the
amount of polyunsaturated fatty acid required for cancer growth is considered to be larger
than that needed of the host. Thus, excessive intake of corn oil is not recommended. [1] In
addition, Chen F and co-workers from University of Miami observed that a significant positive
relation was found between mortality rate and the consumption of dietary corn and wheat flour
in a study of esophageal cancer cases in Shanxi Province, China. [7]
REFERENCE [1] Food uses and health effects of corn oil. J Am Coll Nutr. 1990 Oct;9(5):438-70. [2] Effects of fish
oil, corn oil and lard diets on lipid peroxidation status and glutathione peroxidase activities in rat heart. Lipids.
1989 Mar;24(3):179-86. [3] Phytosterols that are naturally present in commercial corn oil significantly reduce
cholesterol absorption in humans. Am J Clin Nutr. 2002 Jun;75(6):1000-4. [4] Adom KK Liu RH Antioxidant activity
of grains. J Agric Food Chem. 2002 Oct 9;50(21):6182-7. [5] Dewanto V et al, Processed sweet corn has higher
antioxidant activity. J Agric Food Chem. 2002 Aug 14;50(17):4959-64. [6] Dietary corn oil promotes colon cancer
by inhibiting mitochondria-dependent apoptosis in azoxymethane-treated rats. Exp Biol Med (Maywood). 2004
Nov;229(10):1017-25. [7] Corn and wheat-flour consumption and mortality from esophageal cancer in Shanxi,
China. Int J Cancer. 1993 Apr 1;53(6):902-6. [8] Corn Oil, Corn Refiners Association, Online Publication,
November 22, 2005. [9] Lectins as bioactive plant proteins: a potential in cancer treatment. Crit Rev Food Sci Nutr.
2005;45(6):425-45. [10] Fast-Food Fries Cooked in Higher-Fat Corn Oil, Study Shows www.bloomberg.com
January 18, 2010
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Discuss with your doctor before taking any alternative medicine. This article is for
reference only, it is not a medical advice. All rights reserved. Do not copy this article to
other website or blog.
reference only, it is not a medical advice. All rights reserved. Do not copy this article to
other website or blog.
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