Using Citrus in Functional Formulas

By Scott Hegenbart, Managing Editor

Recently, the United Nations recommended people worldwide to consume more citrus fruits and juices. In particular, the U.N.'s Food and Agriculture Organization noted the "array of essential nutrients and compounds found in citrus," and drew particular attention to citrus being a "fat-free source of vitamin C, dietary fiber, folate, potassium and several phytochemicals." In the case of vitamin C, folate and potassium, recent research supports the U.N. recommendation.

Antioxidant connection
A significant amount of research has antioxidant vitamins—vitamin C, vitamin E and the carotenoids—acting as a preventive for ailments ranging from cancer to heart disease. As consumers well know, citrus is rich in vitamin C.

A recent study published in the American Journal of Epidemiology showed that a diet rich in vitamin C may help reduce the risk of chronic obstructive pulmonary diseases (COPD) such as emphysema and chronic bronchitis. According to the National Center for Health Statistics, there are 14 million cases of bronchitis in the U.S. and two million cases of emphysema reported annually. Individuals in the study who consumed a diet rich in vitamin C and who had relatively high levels of vitamin C in the blood had better lung function, and consequently a lower risk of COPD, according to the research.

Participants in the study consumed 151 mg of vitamin C from food sources, about 50% more than the U.S. average. A single 8-oz glass of orange juice provides more than 100% of the daily recommended amount of 60 mg. Two glasses of orange juice could bring people close to the level of vitamin C consumed by study participants. Another option, of course, would be to eat citrus containing food products.

A friend in folate
About 2,500 cases of neural tube defects, such as spina bifida and anencephaly, occur every year in the United States. Research shows that women of childbearing age who eat plenty of foods containing folate may decrease the risk of having children with birth defects.

Folate (also known as folic acid) is a B-vitamin found naturally in foods like spinach, legumes and citrus. Although it is discussed most frequently for its ability to prevent these birth defects, a study conducted at the Medical College of Wisconsin now shows folate may contribute significantly to heart health by helping to control blood levels of homocysteine. Homocycsteine is an amino acid found in the bloodstream that has been strongly linked to increased heart disease risk.

The study was designed to investigate the effects of folate from orange juice on blood vitamin levels and homocysteine concentrations. Twenty-five subjects (14 males and 11 females) ranging in age from 40 to 82 years old, drank 20-oz of orange juice daily (150 micrograms of folate) while maintaining their regular diets. After two months, blood folate levels increased 43%, and homocysteine decreased by 11% within 30 days.

According to Eric Rimm, Sc.D., assoc. professor of epidemiology at Harvard School of Public Health, "There's growing evidence that a diet high in folate can substantially reduce an individual's risk of coronary disease.''

National food consumption statistics show that an estimated 88% of Americans do not consume enough folate in their daily diet. Formulating products with citrus might be one way to help increase consumption.

Beyond bananas
Potassium not only is an essential nutrient, increased intake of it is a must for cardiac patients taking potassium-losing diuretics. Although many consumers think of bananas when they think of potassium, citrus also is capable of providing a generous dose. (8-oz of orange juice provide 473 mg of potassium compared to 451 mg in a medium-size banana.) Now, a Harvard study released in September 1998 reveals that foods rich in potassium and related nutrients may actually help reduce the risk of strokes, particularly in people with high blood proessure.

Animal experiments and epidemiological studies had previously suggested that high potassium intake may reduce stroke risk, but offered no conclusive evidence. Researchers leading the Harvard study examined the association of potassium and related nutrients with risk of stroke among 738 men in the U.S. from 40 to 75 years old. The participants had no previous diagnosis of either cardiovascular diseases or diabetes and had completed a food frequency questionnaire in 1986.

During 8 years of follow-up, researchers documented 328 strokes. The relative risk of stroke for men in the top fifth of potassium intake (median intake, 4.3 g/d) versus those in the bottom (median, 2.4 g/d) was 0.62. Intakes of cereal fiber and magnesium, but not of calcium, were also inversely associated with risk of total stroke. All these inverse associations were stronger in hypertensive than normotensive men and were not materially altered by adjustment for blood pressure levels. Use of potassium supplements also was inversely related to risk of stroke, particularly among men taking diuretics.

Researchers concluded that the data are consistent with the hypothesis that diets rich in potassium, magnesium, and cereal fiber reduce the risk of stroke, particularly among hypertensive men. They also offered that increasing potassium intake alone may decrease the risk of stroke, and perhaps potassium supplements for hypertensives should be more broadly considered. The study does, however, indicate that the results do not support indiscriminate use of potassium supplements. Rather, intake should be increased by substituting more potassium-rich foods.

Citrus in food
With all of the new research on the benefits of citrus, consumers may soon be on the lookout for citrus containing products. Fortunately for product developers, the outlook for using citrus and citrus-based ingredients is good.

"Since 1989—with the significant plantings futher south—we haven't had a freeze and have had larger and larger crops," says Michael Sparks, deputy executive director, Florida Department of Citrus, Lakeland, FL. "Now, we need to think of [citrus] not only for processing into juice, but also as an ingredient."

Formulating with orange juice concentrate, for example, might be one way to add both flavor and desirable nutrients to foods. Thanks to it's naturally occuring sugars and fiber, orange juice also can be used to replace fats and oils, according to the department.

"Orange is the the second most popular flavor, after chocolate," says Sparks. "Why shouldn't there be orange-filled cookies? Why shouldn't there be a line of barbecue sauces or salad dressings that are citrus based?"

But the possibilities don't end with unmodified juice and juice concentrates. The Department of Citrus actively has been performing research to expand citrus applications and to find different forms other than concentrate. One is to use pulp cells as a source of fiber, another is using de-acidified, de-bittered grapefruit juice.

"You can use it as a replacement for apple, grape and pear filler juice," says William Stinson, Jrl, PhD, director processed products research at the Florida Department of Citrus. "It has a much nicer nutrient profile while the others are virtually nil in vitamins."

The department has tested de-bittered, de-acidified grapefruit juices in applications such as sauces and dressings. Another ingredient being tested is orange flour. This ingredient is 74.6% dietary fiber and is capable of extending the shelf life of bakery foods.

Currently, the Department of Citrus is actively seeking processors to commercialize these newer citrus ingredients. With the continuing flow of research demonstrating the positive health benefits, consumer demand will undoubtedly make them available in the near future.

• Photos courtesy of the Florida Department of Citrus.