Cracking the Confectionery Shell

If ever there were a marriage made in confectionery heaven, it would be between chocolate and nuts. Humans have made these sweet creations part of their diets since the earliest days of recorded history.

The first confection might have been the honey and almond paste combination known as marzipan, which appeared among emerging Middle Eastern civilizations and represents an elegant art form in Europe today. Though it lacks North American popularity, marzipan could be converted into design opportunities for U.S. products. Despite the pursuit of low-fat and low-calorie confections having become something of a quest for the "philosophers' stone," the nutritious and healthful content of nuts might outweigh the relevance of their fat levels. Methods for taking advantage of old and new ingredients need to be considered, as opportunities are virtually unlimited.

Nuts to You
Nuts are generally one-seeded fruits of flowering trees. However, peanuts are a two-seeded fruit of the genus Arachis, a legume related to beans and peas.

Nuts' low moisture content allows for blending with chocolates and other fat-based confections. Nuts share the common properties of high-fat, high-protein and low-moisture compositions. Their mineral, vitamin and phytochemical constituents further improve their value in confections. Nuts used in confections generally range from 5% to 30% in protein, with an average of 17%. Fat levels for the same nuts average 58%. Carbohydrates average 16%. Moisture levels range from 2% to 7% in raw, dry nuts, depending on storage conditions.

The high nutrient density of nuts makes them good additives for confectionery use, as 100 grams of nuts will often supply 10% of the Daily Value (DV) of thiamin, niacin and folate B vitamins, fiber, phosphorus and zinc. Similarly, 100 grams of nuts could approach 20% DV for vitamin E, as well as the micronutrients copper, manganese and selenium. Phytochemical contribution of nuts is an important part of their food value. Flavonoids found in nuts are important antioxidants, lowering free radical levels. They reduce the risk of heart disease through inhibiting the oxidation of low-density lipoprotein cholesterol. Ellagic acid, a polyphenol found in walnuts and pecans, can take an active role in tumor suppression. Much more information on the health benefits of nuts is emerging to increase incentives for development of confections using these invaluable additives.

The most widely used nut in confections is the peanut, under development and scientific study since the Civil War. Primary concerns are moisture, oxygen, light, roasting conditions and maturity of the seed for optimum quality.

The almond has great potential in confections beyond its long history. With an average of 21% protein, 14% carbohydrates and 56% fat, and a high level of monounsaturated oleic acid, almonds are quite nutritious. They also contain up to 0.9% potassium, 0.3% calcium and 0.3% magnesium, plus other micronutrients and B and E vitamins. Some tumors are partially controlled by the phytochemicals quercitin and kaempferol found in almonds.

Brazils find applications in chocolate products and healthful snacks. Protein and carbohydrates are somewhat low at 15% and 9% respectively. Fats are high, in the 65% area, but vitamin E is relatively abundant. Cashews are less often used in confectionery, except in butters and pastes. Their higher carbohydrate content (about 26%) makes the texture somewhat mealy, but their flavor is excellent. A protein level of 19% and lower fat level of 43% indicate usefulness as ingredients in confections, although costs are a factor. Coconut has many applications in confectionery. Low in protein, the product is fairly high in fat (61%) and carbohydrates (29%), and the flavor is well-accepted. Hazelnuts have become very popular for confections due to their fine flavor. The macronutrient profile consists of 16% protein, 14% carbohydrate and a 65% fat level; 100 grams of hazelnuts provide about 20 mg of vitamin E.

Walnuts reside among confection royalty. Applications in chocolates and as topping nuts enjoy widespread popularity. Most walnuts used in confectionery are the English variety, although the native American black walnut is also of fine quality. Walnuts run 17% protein, 15% carbohydrates and 62% fat.

Macadamia nuts also are popular, and find use in chocolates, brittles and sugar-panned nuts. They have only 8% protein, 14% carbohydrates and, at 75% fat, are the highest fat producer of the commercially available nuts. Their texture and flavor are responsible for their popularity. Peanuts have high nutritional value, with a 29% protein level. Carbohydrates are 14%, while fat levels are 47%. Allergenicity is a topic to be addressed in product-design discussions. Allergenic reactions to peanuts require product labeling and prevention of product cross-contamination in manufacturing lines. Pecans, like peanuts, are synonymous with the South. They're frequently applied as topping nuts for chocolate confections. Pecans are 16% protein, 12% carbohydrates, with a very high level of fat at 70%. Unsplit or undamaged pistachios are naturally jade green, possessing a sweet and piquant nutty flavor when fresh. They deserve more introduction into confection designs. Pistachios have 21% protein, 17% carbohydrates and 55% fats.

Cracking the quality shell
As might be surmised from nut unsaturated-fat levels, quality control of confectionery nuts is vital to confection quality. From growing conditions to packaging for shipping, all aspects of the process must be tracked. Nuts that have received care in harvesting and drying also must be stored under the best possible conditions - preferably cool storage - for shipment. Shelled nuts can only be preserved by vacuum packing or chilling. Storage at 32° to 38°F (3.0° to 3.3°C) delays the sourness and later rancidity caused by exposure to air. Moisture also must be controlled in storage. Nut kernels generally need drying to 1.5% to 4.0% moisture to prevent oxidation, microbial problems and loss of eating quality. Storage away from light further ensures nutmeat quality, as ultraviolet light accelerates unsaturated oil rancidity. Ingredients must be properly handled throughout the formulation, preparation, packaging and store-delivery stages.

The confectionery manufacturer will generally purchase directly from a nut producer at the production location, ensuring a degree of control over crop quality prior to packing. Many nut crops are grown in tropical climates, with potential for microbiological and insect problems. During the 1970s, heated debate occurred over the presence in peanuts of aflatoxins, carcinogenic toxins of the fungus Aspergillus flavus. Since peanuts grow underground, they're subject to attack by fungi. An environmental factor was found to be moisture level of the soil during peanut growth. Crops are now routinely irrigated. Harvesting, drying and storage are controlled and aflatoxin tests are administered at shipping and upon arrival of the packed nuts. Aflatoxins are controlled below the 1 ppb level.

The allergen-producing potential of nuts requires clear warning labels for nut-sensitive individuals. Peanuts contain the most common food allergen, particularly for children. Peanut allergens often can produce a response at 1 mg exposure.

Making the grade
Grading of nuts is conducted by screen sizes and color detectors. Walnuts, for instance, are sold in four color grades - extra light, light, light amber and amber - which range from a caramel color to a decidedly walnut brown. Sizes range from halves and quarters through a common selection of pieces, passing through 0.625 in., 0.375 in. and 0.25 in. round screens, and resting on 0.125 in. screens. Many custom sizes are available. Almonds are available as flakes as well, due to their stiffer texture. Depending on the type of nut product desired for an application, numerous custom sizes are available for confection designs.

Using nuts in confections requires great skill and control of conditions, as the nuts are subject to spoilage by processing and handling throughout the cycle. Cleanup of the received material after testing consists of removal of shells, stones and damaged nuts from the containers, as nuts are usually purchased shelled. Photometric detection of contaminants is possible where nut color variation isn't a problem. Metal detectors can spot and sort nonmagnetic metals. A useful method for separating extraneous matter is through density separation with air streams, coupled with vibratory screens. Additional hand separation, although very labor-intensive and a difficult step for inspectors, also is required.

Inspected, cleaned and dried, nuts are next roasted for most applications. This step improves the flavor and appearance, but at the same time affects the oil stability. Rancidity can occur more readily after roasting, and thus nuts are not roasted until just before introduction into the confection product. If nutmeats are further reduced into smaller sizes by grinding, they immediately must be coated with chocolate or fats to slow oxidation.

Roasting of nuts for flavor and color attributes requires testing of the raw material and processing under a predetermined set of conditions for a consistent product. The conditions are as varied as the requirements, but generally consist of raising the nuts to the roasting temperature, holding for a determined time to reach an even roast, and cooling fairly quickly for introduction into the confection. To produce the desired quality, it's better to roast nuts at a lower temperature for a longer time than to roast at high temperatures for short times and risk oil damage. Additional testing for oil, moisture levels, color, flavor and texture are conducted on the nuts before proceeding to the confection line.

Confection connection
The entries in a catalog of nut formulations in confectionery would probably exceed a medium-sized town's telephone directory listings. "Roasted almonds and chocolate are a natural," says Sam Cunningham, Ph.D., director, Almond Research Center, Blue Diamond Growers, Sacramento, CA. "Almond butter can be used in bars and in fillings. An opportunity for almond paste exists in marzipan and many confection fillings, though a taste for marzipan has not yet developed here in North America. Hazelnuts are becoming a very popular item in confections. Hazelnuts, with their deep, sophisticated roasted flavor, blend very well with chocolate." Another product that's been doubling in demand every 10 years is macadamia nuts, with their buttery, roasted flavor. This is primarily due to the interest in all things tropical and increased travel by those in the continental United States to Hawaii.

Preparing nuts for inclusion in chocolates requires cleaning and proper roasting. Pre-glazing nuts with a thin coat of chocolate syrup prevents oil migration, and water and detritus contamination from spoiling the nuts. Given low-moisture conditions of less than 1% in the roasted peanut, the coating of brittle, chocolates, low-moisture nougats and glazes is sufficient to maintain good flavor retention in most peanut confections. Proper moisture levels in nuts are critical for shelf life, including crunchy texture, prevention of bloom and flavor problems.

"Proper tempering of chocolate will not lead to bloom problems due to oil migration from walnut meal," says Hans Schneidenbach, master confectioner, Walnut Marketing Board, Sacramento, CA. "Holding the temperature at the proper range for the chocolate will not lead to problems with bloom or separation of cocoa butter from cocoa solids."

Sugar-based confection centers, such as white nougats, won't cause stability problems as long as moisture is low, and enrobing in chocolate might increase the shelf life. White nougats have fairly long shelf life, as long as they are in a high-viscosity, low-moisture state. Basically, sugar and water are boiled to a firm ball stage, at about 130°C (266°F). Egg whites are whipped, and the hot sugar poured into the egg whites while blending. The nougat is blended with walnuts, fruits and flavors, and then cooled. The cooled nougat can be cut into desired shapes.

One basic European confection can be modified into many different products, Schneidenbach explains. Known as gianduja in Italy, the base consists of equal weights of nutmeat, sugar and chocolate coating. The nutmeats are refined to the point at which the paste becomes oily again. Sugar is then added in several steps, refining the blend until the paste is oily again. Cocoa butter is then blended with the milk chocolate coating, which has been tempered at 31°C (88°F ), or with dark-chocolate coating tempered at 32°C (90°F). The chocolate is then refined with the other ingredients. This basic confection serves as the start for formulas containing everything from liqueurs to nut pieces, to nut pastes and flavors. It's used in light to dark nougats, truffles and many fillings.

Oh, what a filling
Nutmeats can be ground into butters and pastes for myriad applications in confection products and fillings. The newer focus on the health aspects of nuts merits consideration by food product designers. Butters processed from nuts - such as peanuts, walnuts and almonds - consist, in the simplest form, of nutmeats roasted and ground into a fine particle size. Chunk-style butters can be produced by modifying the grind size or blending fine- and medium-grind butters in the desired ratio.

Certain varieties of nuts need no oil addition to provide lubricity. Peanuts for butters, with their relatively high carbohydrates and lower oil levels, are augmented with additional cold-pressed peanut oil to achieve the consistency for confection use. Nut butters are relatively stable against spoilage, flavor-quality changes and darkening, provided they're stored at temperatures 70°F or lower. Oil separation is often a problem, requiring the use of stabilizers at about 3.5% in certain applications. Nevertheless, for extended shelf life prior to use in confection products, they also must be excluded from oxygen and light.

By varying the raw material, a variety of butters can be manufactured. "We produce a peanut butter from Valencia peanuts with all-natural ingredients," says Anna Young, plant manager, East Wind Nut Butters, Tecumseh, MO. "We also have an organic peanut butter with the skins left on. The butter from unblanched peanuts yields a darker, more flavorful product." Cashew butter is prepared from nutmeats that are heated to 98ºC (208ºF) to remove moisture but minimize color or flavor changes. The company's roasted cashew butter is roasted to 116ºC (240ºF). Added high-oleic safflower oil provides a spreadable consistency. "Our almond butters are made from mission variety almonds," Young explains. "These are dry-roasted at 130ºC, and are unblanched, so that the butter has a darker, richer flavor."

Peanut butters must contain no less than 90% peanuts, with salt, sweeteners and emulsifiers permitted. Oil content of the butter must not exceed 55%. Preparation of butters proceeds from cleaning of the shelled nuts by air and/or specific gravity separators. The nuts then are either batch-roasted or continuously roasted, in ovens or oil. Ovens are heated to 427ºC (800ºF), with batches being tumbled in the drum to bring the nuts to about a uniform 160ºC (320ºF). They are then held at that temperature for about 40 to 60 minutes to the roast stage desired. "We roast our Valencia peanuts at 280°F (138°C) for 20 to 25 minutes," says Young. "Valencias are smaller than Virginia, or runner, peanuts. Also, we use a light roast to preserve maximum thiamin." Continuous ovens force hot air up the chamber, roasting nuts under turbulence, and discharging the finished product at the bottom of the roaster. Roasting and humidity variations are adjusted to provide a consistently roasted product. Product nuts are then passed through coolers, which draw large volumes of cool air through the product to halt the roasting process.

Nuts may then be passed to grinding for natural, organic butters, or are blanched to remove skins. The blanching can be performed via dry- or water-blanching. Dry-blanching is direct, requiring holding at about 138ºC (280ºF) for no more than 25 minutes, or can be conducted at room temperature. The skins are removed by air blowers. The hearts, which are bitter, are removed by screen separation.

Then medium grinding occurs, followed by a fine grind to yield particles in the range of 0.08 mm to 0.80 mm (0.003 in. to 0.032 in.). Product is often reduced to a finer consistency through homogenization.

Packaging may include reduction of headspace or vacuum packaging. Storing below 15.5°C (60°F) will extend shelf life. Without stabilizers, the oil in the butter might separate slowly and rise to the top. Separation ceases at 10°C (50°F), and flavor changes and microbial growth are managed at refrigeration temperatures of 4°C (39°F).

Nut pastes play a useful role in all kinds of fillings or stand-alone confections. Almonds, walnuts and hazelnuts, among others, all make delicious pastes for confectionery fillings. Ground to a fine, uniform consistency, nut pastes are basically composed of raw nuts (blanched or unblanched), sugar and water.

Marzipan typically has been prepared in milling systems. But Blue Diamond has a completely automated system for production of almond paste that has been increasingly used in marzipan formulations. Almond paste is prepared on a computer-controlled system, monitored for trouble-shooting. Production begins by combining pre-weighed portions of almonds and sugar. These ingredients pass to the processer, where the water and other liquid ingredients are added. Grinding proceeds in the processer mill, where injected steam heats the liquid solution to just below its boiling point, with careful control of the temperature. At the proper temperature, a vacuum pump turns on, drawing off water vapor to a predetermined level - a critical operation for paste quality. The vacuum draw also cools the paste, finally drawing in the correct amount of air to achieve the desired fluffy texture. At the final mixing, almond flavor and preservatives are added prior to packaging.

Packaging is a critical factor in preserving nut pastes. Oxygen-, light- and moisture-barrier packaging is the preferred way to maintain paste quality. Cool storage, below 15°C (60°F), is an effective way to extend shelf life, although pastes are better used fresh than stored for long periods, especially at warmer temperatures. Antioxidants, including vitamin E naturally occurring in the nuts, improve storage conditions. Proper processing - from removal of metal pieces and fines to control of roasting, blanching and moisture levels - will provide a better quality for confectionery use.
Chocolate and compound coatings on a nut-paste confection will allow better quality under controlled storage conditions. Chocolate and compound coatings act as oxygen and moisture barriers during storage.

English walnuts and American black walnuts can be made into pastes for confection fillings and marzipans, offering many confectionery designs. A basic raw marzipan paste can be prepared using about 54% sugar by weight, 17% water and 27% extra-light-color walnut meal. The mix is introduced into a refiner or comminuter, which reduces it to a very fine texture. The raw paste is then blended with an equal weight of sugar plus glucose syrup and/or sorbitol; 3.5% of the marzipan weight can be glucose syrup to prevent crystallization of the sucrose. To preserve the marzipan, it must be at 75% sugars after maturing. The material is cooked to sterilize it. The paste can be flavored, mixed with nut pieces and rolled into sheets or blended with other fillings. Marzipan is a delicacy in itself, which can be used as is, or flavored, shaped or molded into any kind of artistic object.

Systems to go
Systems for manufacture of nut-based confections are generally somewhat involved, and require knowledge of ingredient characteristics and the effects of processing conditions. Many adjustments and control tests are necessary for quality maintenance. Molding chocolate-and-nut candies is accomplished on a large automatic system consisting of: a temperer for chocolates; a depositor for the nut and chocolate blend; the mold system; the cooling system; and the packing line. The system is capable of depositing the confection melt by weight into molds, which proceed through cooling to packing.

An operator closely monitors line control and output quality, as the processes of tempering, depositing, molding, cooling and release of product from the molds are critical to operation and largely automatic on big units.

Shell-type confections, containing a filling covered with chocolate or compound coating, are now prepared on less complicated systems that can produce shell products, as well as bars with multiple fillings and compositions. This equipment prepares shells in a one-step molding of filling surrounded by liquid chocolate, which is chilled and released from the mold. Enrobing is a very useful process for coating all types of confections with chocolates and compound coatings. In brief, bottom-chilled confection centers containing, and/or topped with, nuts are passed via a thin, plastic-mesh screen through a bottom coater. The centers pass over an anti-tailing device to remove dripping chocolate prior to passing over a chill plate to set the chocolate. The centers then pass through the enrobing tank that showers them in tempered chocolate. The covered pieces once more pass over anti-tailing rollers adjusted to remove drippings, but not the bottom coat. The enrobed pieces pass through an air stream that can blow off excess coating, controlling the coating level, as well as chilling the pieces.

Panning of nut confections can include several coating types. Among them are chocolate or compound coatings, as well as chocolate-plus-candy coatings and sugar-coated nuts. Panning is carried out in rotating stainless steel pans, usually by spray-coating the centers with chocolate or other coats. The pans are angled to allow turning and even coating of the nuts. Cool, dry air is directed at the pieces to dry them between cycles. The sequence consists of preglazing the nuts to prevent oil migration to the surface, which can cause bloom. For nuts in chocolate candy, the glaze consists of a thin coat of chocolate syrup containing gum arabic or other gum as well as corn syrup to thicken the chocolate. Corn syrup also serves to prevent crystallization. The chocolate layer is then built up evenly on the pieces by spraying, using untempered chocolate that has been reduced in temperature to 35°C (95°F). The coating is dried with a stream of 13°C (55°F) air at a relative humidity (RH) of less than 60. Finish glazing of the product can be a similar composition to the preglaze, and has to provide a polish that won't crack or fall off. This layer may be applied by pouring it into the pan, in two to three applications with cooling in between with an air stream at about 18°C (65°F) and 50% RH. The product is held at 18°C and 50% to 60% RH for 12 hours until finish coating. The final coating consists of beeswax, carnauba wax or an edible shellac. An edible shellac yields a bright polish, which is applied to the product quickly in a drum turned just long enough to coat the pieces evenly.

Nutmeats have been a ubiquitous part of confectionery. They make sense as candy ingredients for the reasons they always have - flavor, texture and nutrition. With new nut types becoming available, as well as the unique staples already on hand, the focus on health issues points to the nut as the way to inject some nutrition into confections.

© 1998 by Weeks Publishing Company

Weeks Publishing Company
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