Peanut Practicum

With more than 500 million pounds consumed annually, peanut butter might be the best-known use of peanuts in the United States. However, fans of this famed sandwich filling must tip their hats to George Washington Carver. No article about peanuts could be complete without recognizing the improvements in peanut horticulture contributed by this early agricultural chemist, sometimes called the "father of the peanut industry." Carver discovered more than 300 uses for this legume and encouraged its use as a rotation crop to help replenish nitrogen in soil worn out by years of cotton farming.

Today, 70% of domestic peanuts are destined for direct food consumption. According to 2002 USDA figures, the leader is the shelled peanut, with 45% used for peanut butter, 23% for peanut snacks and 21% for peanut candy. In-shell peanuts account for the balance of food consumption. The National Peanut Board, Atlanta, GA, also says that peanut consumption is up in the past four years. Marie Fenn, the Board's president and managing director, attributes this rise to increased promotion and "a consumer who knows the difference between good fats and bad fats."

Four basic types of peanuts are grown domestically: runners, Virginias, Valencias and Spanish peanuts. The runner is most common and the basic ingredient for peanut butter. The Virginia is a much larger peanut used in gift packages. The Spanish variety is the round nut covered with red skin and a Valencia is similar in nature. Either of these latter two types would commonly find a home in a peanut candy bar, such as a PayDay.

Increasingly common among peanut farmers are crop contracts issued by specific corporations. A confectionery company, for example, might be looking for specific moisture levels and/or textural attributes. The contract not only guarantees a purchaser and a price, but also specifies planting and harvesting conditions.

Some people are highly allergic to peanuts. It is the responsibility of the further processor to use good manufacturing practices and clearly label foods that contain peanuts. One industry spokesperson notes that some genetic work has investigated the possibility of producing a low-allergen peanut. The drawback is the same gene controls the nut's taste and flavor. "If you change that gene, you get something other than a peanut," says the spokesperson.

According to Kristen Ciuba, M.S., nutritionist for The Peanut Institute, Arlington, VA, "Peanuts have the most protein of any nut on a 100-gram per-serving basis. They contain more than 75% unsaturated fat and no cholesterol." In addition, peanuts contain 2.2 mg per serving of vitamin E and 41 mg of folate. One ounce of peanuts contains 0.57 to 51 µg of resveratrol, which is believed to help lower cholesterol levels. And recent studies link peanuts and peanut butter with positive effects on type 2 diabetes.

Ciuba adds that peanuts' fat profile uniquely balances mono- and polyunsaturated fat. A 1-oz. serving of dry roasted, salted peanuts contains approximately 14.1 grams of fat: 2.0 grams saturated, 7.0 grams monounsaturated, 4.5 grams polyunsaturated, 4.5 grams of omega-6 fatty acids and trace amounts of omega-3 fatty acids.

"Nutrition scientists are discovering that a balance of unsaturated fats is important to health," Ciuba says. Nutrition research also reveals that peanuts satisfy the appetite. "This might contribute to the beneficial effects of peanuts in a weight-loss diet," she adds.

Finally, a 2003 FDA ruling allows nuts to carry a heart-health claim, with the statement, "Scientific evidence suggests, but does not prove, that eating 1.5 ounces of most nuts, such as peanuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."

Timothy H. Sanders, Ph.D., research leader with the USDA Agricultural Research Service, Market Quality and Handling Research Unit, Raleigh, NC, has done extensive sensory testing on domestic and imported peanuts to develop a lexicon useful for growers and formulators alike. During development, he examined the sensory position of U.S. peanuts in the world market, so sensory analysis includes consumers in both the United States and Europe (United Kingdo, the Netherlands and Germany).

One distinction he discovered is that U.S. peanuts generally have a higher roasted-peanut intensity and a very low frequency of off-flavors, whereas those grown in other countries had some off-flavors. "The off-flavor most noticed in Chinese peanuts was a high bitter note and in Argentinean peanuts the off-note was described as musty," says Sanders. Overall, he concluded that domestic peanuts are preferred.

A fairly novel ingredient is peanut flour. Although in existence for about a dozen years, peanut flour today is more economical than in the past due to changes in the peanut program, a federal plan related to peanut pricing, that helped lower the cost.

Golden Peanut Co., Alpharetta, GA, is the largest U.S. producer of peanut flour. Bruce Kotz, vice president of specialty products, says the flour is partially defatted and is available in a 28% or 12% fat level versus the 48% to 50% fat contained in a full peanut. The fat level, compared to protein, exhibits an inverse relationship: 12% fat flour contains 50% protein and 28% fat flour has 40% protein, while peanut butter, with its much higher fat content, contains 24% or 25% protein.

Kotz says peanut flour will work in any application that uses peanut butter. "Peanut butter is sticky; using it in formulation can clog up the equipment and stick to the container," he says. "Peanut flour mixes easily into formulation without these equipment issues."

In a high-protein bar, a formulator might include peanut flour from 4% to 8%, and in baked goods possibly up to 15%. While it's popular in diet and nutritional or snack bars, other uses include seasoning blends, Thai dressings, sauces and low-carb cookies. Peanut flour also can substitute for some wheat flour in low-carb formulations; however, because it is gluten-free, it doesn't provide structure in baked goods. And, it's an excellent way to add peanut flavor or protein to many products without adding too much fat.

In a peanut-butter-filled confection, used at a level of 4% to 6%, Kotz says the flour acts as a stabilizing agent to help prevent fat migration, while improving texture and making the filling firmer, giving it more "bite," improving flavor, and extending shelf life.

Jeanne Turner is a freelance writer with more than 10 years of experience writing about the functional properties of food ingredients.

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