Kernels of Truth

Stuart Cantor Comments
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Kernels of Truth

April 1997 -- Applications

By: Stuart Cantor
Contributing Editor

    Nuts -- they come in all different shapes, sizes, colors and textures -- and serve as a highly versatile ingredient for food designers.

  Many different plant families supply nuts and are classified as either tree nuts (a one-seeded fruit in a hard shell) or peanuts. Although often considered as such, peanuts aren't really a nut, but a member of the legume family, growing underneath the ground.

  Nuts can be eaten in various ways. Snacking on plain, roasted or boiled peanuts is a favorite pastime at sporting events and circuses. In the food industry, nuts serve many diverse uses. They can be used whole to decorate tops of candies, pastries and pies; chopped or diced to provide texture and crunch in ice cream and cereals; finely ground into a meal for use as a partial substitute for wheat flour, a flavoring agent in baked goods or a thickener for soups.

  Other prepared products from nuts include flavoring extracts, milks (from almonds), stuffings and spreadable pastes. Also, nut "butters" are used in bakery fillings and toppings, candies and cookies. More expensive specialty shops sell oils from almond, walnut and hazelnut. (These topics have been discussed previously in the August 1995 and May 1996 issues of Food Product Design.)

Fat: fact and fallacy

  Nuts have a well-deserved reputation for containing high levels of fat. Many contain almost 50% fat and the fat content of some go much higher. Foods with high calories and fat contents are not always welcome in today's heath-oriented diets and this might have contributed to the steady decline in nut consumption during the past decade.

  On average, Americans consume less than one-half ounce of nuts per day. Nuts account for only about 2.5% of the total fat intake in the Unites States.

  Today, the good news is new technologies allow the production of reduced-fat nuts, flours and nut butters. These enable processors to create various value-added foods with lower fat and caloric content.

  When used in moderation as part of a well-balanced diet, nuts supply more than just taste. They contain the essential fatty acids linoleic and linolenic acids, dietary fiber, phytochemicals and vitamin E. They also contain significant levels of protein and important minerals such as calcium, iron and zinc. Two tablespoons of peanut butter or 1/3 cup of nuts is nutritionally equivalent to one ounce of red meat.

  Soil quality, growing conditions and nut variety all determine nuts' nutrient content, which can vary year to year. Total fat content of nuts ranges from about 45% in cashews to 71% in macadamias. Chestnuts contain the least fat -- less than 3% -- but insufficient market demand exists for them.

  With the advent of the Mediterranean and Asian Food Pyramids, nuts have been grouped with other healthy foods such as vegetables, fruits and legumes and are recommended for daily consumption. This contrasts with the U.S. Department of Agriculture's (USDA) Food Guide Pyramid, which groups nuts together with meat, and only recommends their occasional consumption.

  Another plus is nut fat is composed mostly of beneficial monounsaturates and polyunsaturates with a small percentage of saturated fats, generally 1.0g to 2.5g per ounce. Monounsaturated fatty acids help raise levels of high-density lipoproteins (good cholesterol) without increasing the low-density lipoproteins (bad cholesterol) responsible for atherosclerosis. Polyunsaturated fatty acids lower both types.

  Being a plant product, no cholesterol is present, good news in preventing heart disease and certain cancers. Many recent scientific studies have shown that people who regularly eat nuts, even once a week, had 25% less risk for developing coronary heart disease than those who avoid them. These results have been reported in the June 1994 Harvard Heart Letter; American Journal of Clinical Nutrition (volume 56, 1992); Journal of the American College of Nutrition (volume 11, number 2, 1992); and the March 1993 New England Journal of Medicine.

  Nuts can still be incorporated into low-fat, low-calorie products by carefully adjusting the formulation to use less of them. When trying to reduce the levels of nuts in a formulation, it is best to toast and then cool them before combining with other ingredients, according to Scott Sanders, Ph.D., president, Creative Food Consultants, Byron, CA. Toasting helps intensify nut flavor and can improve the taste of products such as baked goods and ice cream. Toasting does not lower fat content of nuts themselves, but causes formation of pyrazines, which are responsible for a more intense "nutty" flavor. Since the flavor is more intense, a lesser quantity of nuts can be used in a formulation, so the fat content is lowered indirectly. Toasting is performed at temperatures of approximately 250° to 275°F for several minutes.

Almond joy

  Two main types of almonds are grown: bitter and sweet. California is the world's major supplier, but almonds also are harvested from the Mediterranean, Australia and South Africa. Almond oil is extracted from the bitter almond and used for skin-care preparations and flavoring liqueurs and extracts. Sweet almonds are grown for eating.

  Almonds provide excellent sources of calcium and protein, with a 2-oz. serving supplying about 18% of the U.S. recommended dietary intake (RDI) for protein and 15% for calcium.

  Almonds, which can contribute textural contrast and flavor, can be sliced to various specifications from extra thin (0.019 in.) to thick (0.065 in.), says Brad Haney, Quality Control Lab Manager, Blue Diamond Growers, Sacramento, CA.

  A thicker slice might hold up better in a cereal or rice mix, which usually gets shaken around a lot. A thinner slice is fine to use as a cake or pastry topping.

  "The wide variety of almond forms, over 40, makes them a very versatile nut for the confectionery industry, where they are used a great deal," Haney says. For instance, a finely ground meal is available either natural or blanched and can be used to add flavor in soft chocolate centers or in creams and fudges. It can also replace added fat, act as a binder for ingredients and add body.

  Almond skins can be removed by boiling the nuts in water for several minutes (blanching). The net result is a nut with a glossy smooth and white exterior, a subtle taste, and a premium-quality image. In this form, almonds can be used as a topping for dark-colored cakes or chocolate bars to give stark color contrast in almond brittle.

  Almond milks, consumer products made from either blends of rice and almonds or solely from almonds, recently have appeared on the market, according to Chris Heintz, research director, California Almond Board, Modesto, CA. The actual nut content varies, but can be as high as 15%.

  Consisting solely of ground almonds that haven't been blanched, almond butter can replace animal or other vegetable fats. The protein present in the almond butter can also provide some emulsification and keep the fat from readily separating out. It also adds sweetness and richness and provides an excellent source of added protein. Almond butter can be used as a filling for shell-molded chocolates or hard candy.

  To make almond butter, the nuts are dry-roasted at temperatures from 250° to 275°F and are then milled to a smooth consistency by being fed between two rotating plates. Different plates are used with varying gaps between the plates, depending on nut type and size. Because of the low heat and short process time, the shelf-life is not negatively affected.

  Another important use for this nut is in almond paste, a long-time baking-industry staple. It is used as a filling in candy and croissants, macaroons, marzipan, cake frosting and dozens of other products. Marzipan is a sweet, pliable paste made from blanched, ground almonds, sugar and water (glycerin optional). It often is tinted with food coloring and can be molded into various forms including fruits, animals and holiday shapes.

  "There are several parameters that determine the final quality of an almond paste," Haney says. "(These) include the quality of the almonds used, cooking method and mixing process." Good grinding equipment is essential to producing paste with uniform fine particle size which results in a smooth mouthfeel.

  As the grinding process occurs in the mill, steam is injected to heat the water, which in turn cooks the almonds and dissolves the sugar. Heat is increased to within a few degrees of boiling and also acts to sterilize the product.

  "Another critical factor is the final moisture content of the paste, which ranges from 11% to 14%," Haney says. "If it is too high, water can leach out and create sogginess in the dough of the baked products."

  During mixing, the amount of air incorporation will determine whether the paste will have the proper fluffy texture and transparent appearance, Haney says. In the final seconds of the mixing process, a small amount of almond flavoring and a preservative is added, usually potassium sorbate.

Red outside, green inside

  Grown in Asia, the Middle East and the Mediterranean for more than 8,000 years, pistachios have been a coveted food source. However, it wasn't until 1976 that California harvested its first commercial crop of a mere 1.5 million pounds. Today, California is the world's second largest producer with a harvest of 105 million pounds in 1996.

  Pistachios grow in grape-like clusters, encased in an outer skin (hull) which turns rosy when nuts are ripe and ready for harvested. In California, pistachios are mechanically shaken from trees onto a catching frame so they never touch ground.

  "The nuts must be processed (hulled, washed and dried), within eight to 12 hours after harvesting or tannic acid in the rosy hull will stain the ivory-hued shells," says Tom Mack, QA Director, Paramount Farms, Bakersfield, CA.

  Pistachios are dried from an initial moisture content of about 35% to a final moisture of 5% to 6%, Mack says. This lowers the water activity to between 0.5 and 0.6, enabling nuts to have a two-year shelf life.

  Nuts are passed through an electronic color sorter. An air jet rejects any stained nuts. The stain tolerance ranges anywhere from 7% for U.S. Fancy to 35% for U.S. Grade #1. Finally, the pistachios are hand-graded according to USDA standards for size and quality defects. Today, with improved optical- and laser-sorting capabilities, some companies even exceed USDA standards by guaranteeing customers that not more than one shell fragment will be found in 500 lbs. of nuts.

  For shelled pistachios to be labeled as "whole" kernels, 80% of their weight must consist of three-quarters of a kernel. "Whole and broken" kernels must contain 40% whole kernels.

  In-shell pistachios are graded by weight: "extra large" equals 20 or less nuts per ounce; "large" constitutes 21 to 25 nuts per ounce; "medium" is 26 to 30 nuts per ounce; "small" equals 31 nuts per ounce. Finely chopped nuts can be used in sauces; nut pieces would be suitable in meat dishes and salads.

  "Pistachios were once viewed by consumers only as an upscale nut for snacking due to their short supply and higher prices, but this is no longer the case," says Karen Reinecke, president of the California Pistachio Commission, Fresno.

  The nuts were only eaten as a snack in the past but today, they are used as ingredients in many different foods, as consumers have discovered they add an interesting color and nice flavor to ordinary foods. The pistachio's rich, buttery flavor and vivid green color are lending themselves to many food products.

  In sensory testing of prototype samples, they are gaining consumer appeal, Reinecke says. "Recent surveys have shown that consumers are willing to pay a premium of 5 to 10 cents more per serving for meals prepared with pistachios as opposed to other nuts," she says.

  The pistachio shell's native hue, as opposed to an artificially created red casing, enjoys increasing consumer acceptance.

  "Dyeing of the shells with a solution of FD&C Red #40 is optional and done to meet the needs of certain markets that wish to buy the nuts with red shells," Mack says. "The nuts are placed in a tumbler and the dye is atomized onto them to ensure an even coating. Today, however, this market is very small and declining."

  Europeans have used pistachios in sausages, deli meats and pâtés. In the United States, new recipes developed by the California Pistachio Commission include mayonnaise, chutney, biscotti and pasta. Also, pistachio butter's high protein content allows it to be used as a natural thickener, emulsifier and binder. When used in place of heavy cream, it can help reduce saturated fats and eliminate cholesterol in pastry fillings, truffles and other chocolate confections.

  Ground pistachios can be used in coating applications such as in a Caribbean breading for seafood and chicken. Another new application for finely diced pistachios is in frozen novelties such as drumstick cones or molded stick bars. The nutmeats can be either blown on the outside surface or included in the chocolate coating. This application requires small pieces, typically specified as not more than 10% retained on a 16/64-in. round opening, and not more than 3% through a 5/64-in. round opening.

  For high-moisture applications such as ice cream, it is important to use oil-roasted pistachios, says Mack. "Because pistachios are hygroscopic and readily pick up and retain moisture, the oil acts to coat the outside surface and prevent them from becoming soggy in the final product."

  "For nuts to retain their particular shape and identity in ice cream, they should not be added into the mix at the start, but should be added separately to an ingredient hopper that has been connected to the continuous freezer," says Phil Keeney, Professor Emeritus, Pennsylvania State University, State College, PA. "The corkscrew auger inside the hopper will carry the nuts slowly into the mix so they can be distributed uniformly."

  Before feeding the nuts into the hopper, it is important to equilibrate them as close to the temperature of the ice cream (0(F) as possible, Keeney says. Otherwise, ice crystals will form around the nuts, making the product unacceptable to the consumer. Generally, the level of nuts varies from 3% to 6% of the mix.

From England and elsewhere

  Seventeen known walnut species grow throughout the world, from the Mediterranean to Eastern China. The two most popular varieties are English walnuts and black walnuts. California is the world's leading producer of English walnuts, which also are the most widely available. The black walnut is a North American native with an extraordinarily hard, difficult-to-crack shell.

  Walnut oil, used for centuries as a drying agent in artists' paints, also is a popular cooking oil in France and currently is used in several gourmet vinaigrettes.

  Resembling the human brain in shape, this extremely nutritious nut is naturally low in sodium, contains about 10% dietary fiber and protein, and includes important vitamins and minerals such as thiamin, folacin, iron, zinc, magnesium and potassium.

  Available year-round in-shell, walnuts come in five main sizes: jumbo, large, medium, standard and babies. They also come in a wide range of colors classified by the USDA as "extra light," "light," "light amber" and "amber." A chart is utilized to document color.

  Shelled walnuts come in the following sizes: halves (85% or more by weight); pieces and halves (20% or more by weight); pieces (those that cannot pass through a 24/64-in. screen) and small pieces (those able to pass through a 24/64-in. screen, but not a 8/64-in. screen).

  "Walnuts have a unique texture and a delicately mellow, yet slightly astringent, flavor primarily due to naturally occurring phenolic acids," says Nicole Kenyon, Consultant, Thomas J. Payne Market Development, Burlingame, CA.

  "Interestingly, this distinct flavor note can be used to enhance the flavor of many products, such as chocolate, cinnamon, ginger, orange and vanilla."

  At 7:1, walnuts have the highest ratio of polyunsaturated to saturated fats as compared to other nuts, Kenyon says. "The good side to this is that essential polyunsaturated fatty acids, such as linolenic and linoleic, have been found to effectively reduce serum cholesterol by more than 10% in some people. The downside is that this nut tends to undergo oxidation more readily under unfavorable storage conditions, and this results in the production of compounds causing off-flavors."

  Generally, all nuts should be stored in a cool, dry place without the use of ammonia coolants and away from any strong odors, which can be absorbed. Chopping or slicing walnuts before using them can accelerate rancidity by increasing the exposure of the unsaturated fatty acids to oxygen. The optimum refrigerated storage conditions for walnuts are 0° to 3.5(C at 2% to 4% moisture and 55% to 65% relative humidity. Under such conditions, shelf life can be as long as 18 months.

  Inside the shell, walnut kernels are surrounded by a special protective coating known as the pellicle. This covering is only 5% by weight, but rich in several compounds that help protect the nut against oxidation.

  "Both (-and (-tocopherols and also ellagic acid act as natural antioxidants," Kenyon notes. "The presence of other antioxidants such as gallic acid, methyl gallate, juglone and tannin have also been reported in the literature."

  Additionally, if requested, the U.S. Food and Drug Administration and the USDA allow walnuts to be sprayed with BHA or BHT. The USDA permits combinations of antioxidants up to 0.02% (200 ppm) or single antioxidants at 0.01% or 100 ppm of the fat weight. The cereal industry often specifies the use of BHA- or BHT-treated walnuts to insure an acceptable shelf life.

  In the United States, walnuts have mostly been used in the baking industry, particularly in muffins, breads and cakes, according to Nathan Holleman, marketing director, Walnut Marketing Board, Sacramento, CA. However, breaking with tradition, walnut milk recently has appeared on the West Coast.

  Another novel application is in vegetarian entrees as a pasta filling or in pasta sauces. In Europe, walnuts are used in fresh sausages, processed meats and even cheeses. Ground into a paste or butter, walnuts make an excellent pastry filling.

  The Walnut Marketing Board conducts contests around the world in order to find the most innovative recipe and uses for this nut. "A 'Bake with the Best' contest is sponsored annually in America," Holleman says, "and last year's winner was a walnut tart with raspberry topping."

'Hazel-y' outlook

  Hazelnuts, also called filberts, are appearing in more food products these days as their popularity with consumers increases. They can be roasted, sliced, diced or further processed into flour, butter, paste or oil. Nutella, a creamy, chocolate hazelnut spread, has enjoyed European popularity for years.

  While Oregon produces 99% of the domestic crop and Washington state the remaining 1%, this production accounts for only about 4% of the total world production. Turkey grows the bulk of hazelnuts, followed by Italy and Spain.

  Hazelnuts are a rich source of nutrients. One ounce of nuts supplies 75% of the RDI for vitamin E and 31% for vitamin B6. Hazelnuts also are a good source of protein, iron, calcium and dietary fiber. Hazelnut oil has a fatty acid composition quite similar to that of olive oil, which is considered by nutritional experts to be "heart-healthy."

  After washing to remove any foreign material from the outer shell, hazelnuts are dried under carefully controlled conditions for one to three days, obtaining a final moisture content of 4% to 6%. These are referred to as "natural" or "raw." Roasted or baked nuts contain about 2% to 3% moisture. This corresponds to a water activity (Aw) of about 0.46 to 0.49, a level that does not support microbial growth. The low water activity, along with high vitamin E levels, hinders fat oxidation and off-flavor development.

  Hazelnut skin should be red-brown to dark brown with cream- to tan-colored kernel flesh. A colorimeter is not typically used to measure this. Off-color generally indicates poor quality. Shelled hazelnuts, both raw and roasted, should conform to the following size categories: whole; diced (approximately 1/16 inch to 3/8 inch); sliced; whole; and broken (whole nuts, halves and smaller pieces).

  "For bakery applications where color is important, their brown skins can be removed by heating them to 350(F for 10 to 15 minutes, until the skins begin to flake," says Karen Lobb, promotion manager, Hazelnut Marketing Board, Portland, OR. "The roasting process also helps to improve the flavor of the nut considerably." Hazelnut's mild, sweet flavor is compatible with various foods and flavors. "Surprisingly, the flavor is found in the carbohydrate fraction, rather than in the kernel fat and, as a result, is more easily extracted and concentrated," Lobb says. "Volatile flavors are developed by chopping, grinding or roasting."

  A big market currently exists for gourmet coffees and creamers flavored with hazelnut extract, says Lobb. A hazelnut-flavored beer even is on the market. Currently, the Hazelnut Marketing Board is promoting using hazelnuts in bagels and decadent desserts such as cheesecakes, ganaches and log rolls.

The $4 billion nut

  Enjoyed for thousands of years as a crop of South American origin, peanuts are now widely grown all over the tropics and the southern United States. Today, peanuts contribute more than $4 billion annually to the U.S. economy.

  In the United States, four main types of peanuts are grown: Runner, Virginia, Spanish and Valencia. These vary in shape, flavor and appearance and also have differences in nutritional makeup.

  Choice of variety depends on processors' tastes and the U.S. market. In general, Virginia and Valencia varieties are eaten in-shell. Confectionery and snack applications use Spanish as well as some Virginia peanuts. Most Runners are used to produce ingredients, including oil.

  "There are two basic types of peanuts used by the confectionery industry that differ considerably in size and flavor: the Spanish and the Virginia," says Mary Webb, executive director, Texas Peanut Producers Board, Gorman, TX. "The Spanish peanut is small, quite highly flavored and high in oil. It is particularly suitable for manufacturing peanut brittle and peanut butter. On the other hand, the Virginia variety is quite large and has a milder flavor. They are used mainly for peanut bars and for salted peanuts."

  After harvesting, peanuts are cured or dried to a moisture as high as 8% for in-shell peanuts; to 5% for stored, raw peanuts; or as low as 2% for shelled ingredient peanuts. If peanuts are dried to quickly at too high a temperature, they can develop bitter flavors. The same kind of improper drying also can promote split nuts.

  After drying, peanuts can be dry- or water-blanched, and then roasted, to develop flavor and color. Blanching can remove some of the tannins and other bitter compounds present in the skins and germ. In confectionery products, peanuts always are roasted, as in their raw state they are inclined to be slightly bitter and soggy, Webb says.

  Peanuts are extremely high in protein; about 26g/100g and contain 40% to 50% oil. Peanuts also provide an excellent source of iron, zinc and dietary fiber.

  The composition of the various types of peanut varies slightly. Other factors that can influence their nutritional makeup include cultivar, crop location and conditions, maturation and storage conditions. Runners contain a larger oleic-to-linoleic acid ratio and a higher tocopherol level. This increases storage stability. As a peanut increases in maturity, its protein content increases and free amino acid level decreases. This can affect the flavor, because arginine, an amino acid present in immature peanuts, causes a bitter taste.

  Peanut oil is used for cooking foods and also in salad oils and margarines. The oil has a very high smoke point (450(F), making it an excellent frying medium. Additionally, it also does not absorb or transfer flavors, so the same oil can be used repeatedly to cook different foods. Peanut oil contains a slightly higher level of saturated fats than soybean and about 50% monounsaturated fatty acids, such as oleic, which makes it fairly stable to oxidation.

  Recently, plant geneticists at the University of Florida at Gainesville developed a peanut with 80% oleic acid and only 2% to 3% linoleic acid, called SunOleic 95R.

  "Roasting regular nuts in oil from high oleic peanut lines extended shelf life by 20% to 30%," says Tim Sanders, plant physiologist with the USDA's Agricultural Research Service in Greenbelt, MD.

  Sanders says he thinks the reason for this phenomenon is that the fatty acids in the high oleic oil are more stable against degradation, since the majority of them are monounsaturates rather than polyunsaturates. "The oxidation of the fatty acids produces the off-flavors that consumers find objectionable", he says.

  Peanuts also can be partially defatted, says Bruce Kotz, specialty products manager, Golden Peanut Company, Alpharetta, GA. "Several major candy companies are looking at using this ingredient to give their products a more healthful image by cutting fat and calories." For some applications, a good flavor system must be selected to add flavor back to the food, Kotz says, since some of the peanut flavor will be removed along with the fat.

  Peanut flour can be partially defatted to levels ranging from 12% and 28% fat, quite good considering peanuts start out with more than 50% fat. Peanut flour is used in many ways, including: high-protein drinks and nutritional bars, diet bars, frostings, fillings, baked goods and seasoning blends. "Because peanut flour is partially defatted, it works well as a fat binder in confectionery centers," Kotz says. "When used at levels of between 4% and 6%, it can extend the shelf life and contribute flavor."

  Developed in 1890 by a U.S. doctor and promoted as a health food, peanut butter is a blend of ground, shelled peanuts (blanched or roasted nuts may be added), vegetable oil (often hydrogenated) and usually a small amount of salt. Some commercial retail brands contain sugar and emulsifiers to improve creaminess and prevent the oil from separating. It is sold in two forms: smooth or chunky.

  Natural peanut butter uses only peanuts and peanut oil and must be refrigerated upon opening. Commercial peanut butters can be stored at room temperature for up to six months. The FDA-issued standard of identity for peanut butter states that "peanut butter must contain at least 90% peanuts and cannot contain any artificial colors, flavors, sweeteners or chemical preservatives, and that the fat content of the finished food shall not exceed 55%. The remaining 10% may be salt, sugar and/or an emulsifier."

  These are only some of the nuts that are used in food products. While applications for nuts are just as diverse as the forms they take, food designers are continually developing new uses for these versatile ingredients. Recent scientific studies only confirm what people around the world have known for centuries: that eaten as part of a well-balanced diet, nuts add much more than just taste. They also provide many essential nutrients, enhance food value, and are beneficial for maintaining good health.

Not Quite Nuts

  Like peanuts, sunflower kernels are not true nuts, but share many of the same applications. They're frequently seen as additions to cereals and baked products, as a topping, or roasted and salted for use as a snack.

  The plant that produces these kernels is known as the confection sunflower, or the non-oil or edible sunflower. These make up approximately 15% to 20% of the sunflower crop. The rest of the crop consists of oilseed varieties.

  The confection sunflower's characteristic black-and-white-striped hull loosely holds the edible kernel. Whole seeds are graded by size: large (retained by a 22/64-inch round hole sieve, or RHS); medium (through a 22/64-inch RHS) and small. The large seeds typically become in-shell snacks and the small seeds are used as pet and bird feed.

  Usually, the medium seed is hulled and the kernel is sold either roasted or raw. Direct sizing after hulling shows that most kernels fall into the 12/64-inch to 14/64-inch RHS. Sizes can be customized for a particular application. Sunflower chips (broken kernels) also are sold as food ingredients.

  According to standard specifications, there are not more than 650 whole kernels per ounce. Chips must be retained on a 8/64-inch (round hole) sieve. The product should contain no more than 10% broken kernels of less than half of the whole meat.

  Sunflower kernels contain three polyphenol compounds: chlorogenic, caffeic and quinic acids. Chlorogenic acids cause the kernels to irreversibly turn green when exposed to alkaline conditions. Two techniques can keep this color from becoming noticeable. First, a dark product can be formulated, using ingredients such as rye, chocolate or molasses. The second method involves acidifying the formula with food-grade acids or acidic fruit ingredients.

  According to Connie Hofland, marketing director at the National Sunflower Association, Bismark, ND, consumer surveys conducted by the organization show that "consumers rate sunflower seed the 'healthiest' compared to other nuts and seeds. This healthy image is well-deserved; sunflower seeds are high in a number of nutrients including vitamin E and zinc. Adding sunflower kernel adds nutrition, texture, taste -- often at a cost advantage (to other nuts and seeds)."

  That "good-for-you" reputation is supported by high contents of iron (7%) and dietary fiber (14.3%), and a protein level comparable to that of peanuts (23%). Sunflower kernels also are considered a good source of potassium, thiamin and vitamin E, and contain high quantities of linoleic acid, an essential fatty acid that appears to decrease blood cholesterol levels.

  Like nuts, sunflower kernels contain fat levels of approximately 50%. Most of this fat is polyunsaturated (69%) or monounsaturated (21%), so it can be prone to oxidative rancidity if stored improperly. However, if moisture content is 10% or less, kernels can achieve a one-year shelf life when stored below 60(F with 40% to 60% relative humidity. Low oxygen storage conditions, such as nitrogen-flushed packaging, also can increase shelf stability.

TABLE:

*(not included in print version due to space considerations)

Table 1. Nutritional Content of Nuts (mean values
per 100 g edible portion)

Nut

Protein (g)

Calories

Total Fat (g)

SF*

%

MUF*

%

PUF*

%

Vitamin E (mg)

Iron (mg)

Fiber (g)

Calcium (mg)

Almonds

20.0

589

49.8

9.9

68.1

22.0

24.7

4.2

2.7

250

Brazil nuts

14.3

656

63.3

25.5

36.4

38.1

0.3

2.8

2.3

180

Cashews

15.3

574

44.3

20.6

61.7

17.7

1.8

6.0

0.7

45

Hazelnuts

13.0

632

59.7

7.7

82.2

10.1

24.7

3.3

3.8

141

Macadamias

8.3

702

70.5

15.6

82.5

1.9

0.4

2.4

5.3

40

Peanuts

25.8

567

46.8

14.5

52.2

33.3

7.1

4.0

4.9

92

Pecans

7.8

667

64.3

8.4

65.6

26.0

3.5

2.4

1.6

73

Pistachios

20.6

577

46.1

13.2

70.9

15.9

7.1

6.8

1.9

140

Walnuts (English)

14.3

642

53.9

6.7

23.6

69.7

2.5

2.4

4.8

94

*SF = Saturated fatty acids, MUF = Monounsaturated fatty acids, PUF = Polyunsaturated fatty acids. All fatty acids are calculated as a percentage of the total fat.

Source: USDA Handbook #8, Composition of Foods (1991).
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