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A Pasta Primer
January 1, 1995
22 Min Read
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Back to Editorial Library By: Lynn A. Kuntz
Pasta is one of those products that seems universally accepted -- unless the folks at the Center for Science in the Public Interest catch you pouring Alfredo sauce over it, that is. It's healthy, it's multicultural and it's inexpensive. It shows up in practically every aisle of the supermarket as a stand-alone product, in prepared dry mixes, in canned products, and in the refrigerator and freezer cases. Product designers love pasta because it makes a great starting point for innovative development. But, like many things, there is more to pasta than one would expect.Ingredient inventory Pasta refers generically to dough-based products such as noodles, macaroni and various specialty items. In this country, the FDA has issued standards of identity for macaroni and noodle products in 15 different categories. Essentially, pasta is divided into two areas: macaroni or egg noodles. "The term pasta actually does not appear in the standard of identity," notes Rob Vermylen, vice president, A. Zerega's Sons, Inc., Fair Lawn, NJ. "This could create a problem if someone is unaware of the fact, giving the 'unscrupulous' license to juggle formulas to make things that truly are not pasta and call them pasta. "Most of us in the industry do call these two products pasta," he continues. "It would be desirable for the industry to have included pasta in the standard of identity." The basic raw material for most pasta products is durum semolina which comes from durum wheat, a hard spring wheat. It is primarily grown in North Dakota and the surrounding region. The standards of identity allow semolina, durum flour farina or flour, but industry experts unanimously agree that durum wheat makes the best pasta. The premium ingredient, durum semolina, is a granular form of flour taken just from the endosperm. It produces pasta with the best color, a characteristic amber yellow. Durum semolina gives the best resistance to overcooking, lack of starchiness, firm bite, and characteristic, almost nutty flavor. In Italy, durum wheat is mandatory for pasta products. Mixing in other kinds of hard spring wheat gives a whiter pasta, softer bite and less resistance to overcooking. Any flour with starch damage from processing or growing conditions can degrade the quality of the finished product. The ash content of the flour affects the texture -- the higher the ash, the softer the texture. "When you are dealing with pasta, an al dente texture is important," says Harlan Jemison, director of foodservice ingredient sales, Dakota Growers Pasta Co., Carrington, ND. "That is a function of the thickness of the finished product, as well as the blend you are using." Most semolina and durum wheat used in the United States is enriched with the B vitamins. A very small percentage of pasta -- formulated for the natural foods category -- forgoes fortification because the B vitamins are not naturally derived. "One interesting subtlety of the labeling laws is that they do permit pasta products that are not enriched," notes Sanford Wolgel, Ph.D., industrial sales, Conte Luna Foods, Philadelphia. "However, several states, including New York and California, prohibit the sale of pasta that is not enriched. This point has an important bearing on a food manufacturer's desire to label a product 'natural.' Enrichment vitamins, although indistinguishable from their natural version, are synthetic. Thus, it is not possible in major marketing areas of the United States to sell a product that conforms to a standard of identity for a pasta and label it 'natural.' " Egg noodles are generally not made with semolina but with durum flour, which comes from the same wheat as durum semolina but has a finer granulation. Classic egg noodles are thin, so semolina, a granular product, would plug the outlets in the noodle die. An egg noodle contains 5.5% egg solids on a dry basis, using whole egg, egg yolk, or any combination of the two. "One would tend to use egg yolk versus whole eggs when you are striving for the brightest color," Vermylen recommends. "More typical applications using whole egg give the color benefit of the yolk, but you also get the protein in the egg white which improves cooking quality and gives you a firmer bite. That's important with noodles because they are generally very thin and tend to overcook quickly." Macaroni consists of durum semolina and water. Other ingredients may be added according to the standards of identity. For instance, vegetable macaroni contains a minimum of 3% vegetable solids. "There aren't that many vegetables allowed: tomato, spinach, beet and some others," says Vermylen. "Technically, all the different varieties you see today aren't included in the standards of identity. That's only because when they wrote the standards, in their wildest imagination they didn't dream of using much other than spinach and tomato. "As you replace durum semolina with vegetable, you hurt the cooking quality," he continues. "We add the vegetables at 4% because we're trying to get a darker color and more flavor. If you go over 4%, particularly in the tomato because of the acidity, you get a definite decrease in the cooking quality."Beyond the standards Besides the products that meet the standard of identity, there are small amounts of product manufactured containing ingredients such as rice, quinoa and amaranth. These are generally created for specialty markets, including health foods or medical diets such as those for patients with wheat allergies. The Japanese make buckwheat pasta. The protein content of this type of grain is much lower than durum wheat. Therefore, these products are softer and lose more starch when cooked. "The protein is the backbone of the pasta, and it helps to hold the starch in," explains Conte Luna Foods' Wolgel. "An electron micrograph of pasta shows how the starch is embedded in the protein matrix. Pasta made with these other kinds of flour is very easy to overcook, and it doesn't have a very firm texture once cooked. There are some gelatinous Oriental noodles with potato starch in them. Also, in the kosher food industry, their has been some work with making a kosher for Passover noodle with matzo meal and potato starch." Pasta can be enriched with nutrients other than the B vitamins. Protein, generally in the form of soy protein or egg white, are commonly added to pasta. At least 20% of the finished product must be protein, and at least 95% of that must be casein. The Code of Federal Regulations also allows added iron at 16.5 mg per pound and added calcium at a level of up to 625 mg per pound in macaroni and noodle products. Noodles also may be enriched with vitamin D. "Without enrichment, the protein level of pasta is quite high," remarks Dakota Growers' Jemison. "Most pasta has a protein level of approximately 12% to 14%." The standards allow additional ingredients -- namely, egg albumen, alginate and glyceryl monostearate -- to strengthen the pasta for severe process conditions. Egg albumen increases the protein content and strengthens the network that retains the starch during cooking and gelatinization. Glyceryl monostearate complexes with the amylose to form insoluble helical structures that also retain the starch and minimize water absorption, both of which would otherwise lead to unacceptably soft product. Carrageenan can be added to pasta containing nonfat milk. Disodium phosphate may be added to speed cooking. Other ingredients have been successful]y added to pasta products, most notably fiber and flavorings such as herbs and spices. Technically, however, most of these ingredients are not included in the standards of identity for macaroni and noodles, except for onion, celery, garlic and bay leaf. The standards specifically do not allow artificial colors, artificial flavors, artificial sweeteners, chemical preservatives or starch. "In the last 10 years there has been a huge increase in the types of flavorings added to pasta," says Vermylen. "I'm not certain they are even included in the standard of identity. Some of the herbs and things like that are included. In reality, the spinach and tomato are in there mainly for color. The whole category of flavored pastas -- the garlic, lemon-dill, basil -- is pretty much of a specialty category." Pasta with sufficient fiber to make nutritional claims has been formulated on an experimental basis. Technically, additives with relatively high fiber levels, either soluble or insoluble types, are used to maintain an acceptable protein matrix and preserve the texture. "It might affect the drying somewhat, but we've frequently done it," claims Wolgel. "We've had to adjust the drying process. With the emphasis on nutraceuticals, I believe that pasta is positioned to enter that area. It can be a good carrier for these types of nutrients."Manufacturing macaroni The government may limit what goes into the pasta and give a few finished-product guidelines, but it doesn't say how to make the product. Several methods are possible; all begin with adding water and mixing a dough. The dough contains about 30% moisture to facilitate handling and forming. Pasta manufacturers mix the dough in a batch or continuous mixer for about 10 minutes, until the dough is uniformly hydrated and mixed. This activates the gluten. Uniformly mixing the dough helps give even extrusion. Applying a vacuum to the dough at either the mixing stage or in the extruder at the kneading stage removes the air from the dough. This improves the color and lends a translucence to the product. Some say that it also improves the cooking quality. Pasta made without a vacuum has a pale appearance. Two methods are used to form pasta. 'The first, and most common, uses extrusion under pressure through a die. The second method uses a sheet which is often laminated, or folded, to make a series of layers. Lamination can increase the elasticity of the dough. A series of rollers reduces the thickness of the dough sheet, which is either stamped or cut into noodles. "Kluski noodles are made with laminated sheets," says Wolgel. "That gives an old-fashioned, very al dente texture. A lot of soup manufacturers use them. They also seem to hold up well in frozen foods. You have to use a sheeting process if you add a particulate like a basil flake because something like that will clog an extruder." With the extrusion method, the dough is transferred into a rifled cylinder through which an auger screw runs. The auger transports the dough to the die, and the kneading takes place at high pressure. The pressure is critical to the kneading function to activate the gluten. Poor gluten development results in a finished product with poor strength and cooking characteristics. The cylinder has a water jacket to cool it down from heat generated by the friction. If the temperature rises over 120°F, the gluten can break down. The dough passes into a cone-shaped chamber fitted into the extrusion die. The cone aids in giving an equal distribution of pressure within the die so that all of the pasta comes out at the same speed. The speed of extrusion affects the pasta's length. A rotating knife for cutting the pasta is fixed on the outside face of the die. The length of the pasta is determined by the speed of the knife. The large, round dies are primarily made of bronze or a combination of aluminum and bronze. The dies contain hundreds of inserts that determine the actual shape. These inserts can be tipped with Teflon or left as natural brass. "There are two different schools of thought as to which makes better pasta," Vermylen observes. "The Teflon tipping wipes the surface of the pasta as it passes, giving the surface of the pasta a smoother appearance so the light reflects off of it differently. It produces a brighter yellow color. Because the bronze is not as smooth as Teflon, it gives a rough surface to the pasta. Traditionalists will tell you this gives a better cooking quality and that the sauce sticks better to it. For retail pasta, sold dry on the shelf, Teflon dies are the choice because they improve eye appeal. For canning, freezing or other applications where the control of the shape is important, the bronze die gives better results. That's because with the pressure the die is operating under, it's much easier to nick or distort Teflon dies, causing inconsistent shapes."How dry it is After exiting the press the pasta contains about 29% to 30% moisture. The first step in drying involves rapidly removing the surface moisture from the pasta with a piece of equipment known in the industry as a shaker, which consists of a large box with a series of pitched screens. The pasta moves continuously in one direction through two or three levels and has hot, dry air blown through it. This step prevents the hot, wet pasta from sticking together, and it can help maintain the shape. Some of the bigger shapes would tend to flatten out without this step. This process takes the moisture to about 28%. Most pasta manufactured in this country is dried to a moisture level of approximately 12% for shelf stability. Some, however, is packaged frozen or under refrigeration. Depending on the product requirements, the pasta is either frozen or refrigerated at this point or it undergoes further processing. According to industry sources, in order to increase the shelf life of retail refrigerated pastas, the product is quickly dried to reduce the moisture and then is sometimes steamed slightly before it is put into gas-flushed packaging. This can allow the pasta to achieve a refrigerated shelf life of up to 12 weeks. Shelf-stable, or dried pasta, goes through a two-step drying process. In the first step, which takes about 30 minutes, the moisture is reduced to approximately 20%. Depending on the size and shape of the pasta, the second stage of drying can last anywhere from three to seven hours or longer, dropping the moisture to a target of 12%. The temperatures used range from 140° to 17O°F. Using the older, "hand-crafted" method with temperatures around 110° to 120°F, the drying stage can last 36 hours or longer. Pasta manufacturers use large belt dryers with six to nine different levels. The pasta goes in the top and is distributed evenly, at a depth of 1 to 6 inches, across a 6- to 8-foot-wide belt. It travels to the end, drops to the next level and, as it drops, it turns over so that different parts get exposed to heated air as the pasta descends from level to level down the dryer. Monitoring the temperature and the relative humidity is critical to the speed of drying. In the preliminary step, the pasta is dried rapidly by maintaining a low relative humidity in the dryer. The speed of the belt controls the throughput, or pounds dried per hour, and an automatic thermostat controls the temperature. Relative humidity inside the dryer is monitored; if the air becomes too wet, the hot air is exhausted and dry, ambient air is brought in and heated by the radiators. This occurs as often as once a minute. "There are different ways of drying," explains Vermylen. "Some people dry at low temperatures, the traditional way. The new technology is to dry at higher temperatures to cut the drying time. Some companies dry at temperatures as high as 200°F at certain stages. This is called high-temperature drying, and it doesn't give you as much margin of error. There are studies showing that the high-temperature drying, correctly done, can improve the cooking quality and color, reduce the microbial load, and increase its resistance to overcooking." Besides shortened production times and improvements in quality, the very high temperature processing can provide another advantage. Using higher temperatures inactivates more enzymes, such as oxidase, that may be present in the flour or other ingredients. Drying at higher temperatures also can cause problems if the process is not done correctly. Among the problems are denaturation of protein and loss of nutritional quality of the protein. The effect is relatively minor as it applies to total protein, but the loss of some lysine has been reported. Another problem that may occur more readily is browning through the Maillard reaction. This can be prevented with tighter control of the processing conditions, especially temperature and time. "If there is a problem with the color, it will almost always show up in the thinner pastas like the angel hair and the linguine" notes Jemison. "It's not actually caramelized, but you may have a wider variation in the color." In the preliminary drying stage, moisture can be removed rapidly because of the pasta's high moisture level. But if the process conditions are not properly controlled the pasta will case-harden, trapping the moisture inside. That leads to what the industry calls checking. Although the finished product moisture may be correct, the center moisture level is too high. The moisture migrates to the surface later, creating pressure inside the product which causes the pasta to crack. This may occur relatively soon after drying or appear days later, causing the pasta to shatter when cooked. "Sometimes people get confused because there can be little bran flakes in the flour itself or other visual defects in poor quality raw materials that give the appearance of checking," notes Wolgel. Dramatically raising the relative humidity (RH) in the second stage slows the rate of drying, but also prevents checking and maintains the quality. It equalizes the moisture between the center of the pasta and the outside. A high RH also improves the color of the pasta. Drying the pasta too rapidly on the outside results in a drier, whiter appearance. The final stage of drying cools the pasta to prevent heat-shock when it reaches the cooler ambient air. The pasta is approximately 160° to 170°F when it exits the dryer, so it requires a cooling period of about 20 minutes. This lowers the temperature to about 100°F. "After drying, the target moisture is 12% -- whether the product is macaroni or egg noodles," Vermylen says. "Drying conditions change drastically depending on the shape of the pasta. Very fine egg noodles like those used in noodle soup only take a couple of hours. Heavier, denser shapes like orzo take significantly longer to dry. This particular shape is thicker and as it rests on the bed it packs more densely together, making it harder for the air to blow through."Shapes and specs The moisture of the product is critical to finished product quality. The product should fall into the 11% to 12.5% moisture range under average relative humidity. Pasta will pick up moisture in humid conditions and lose moisture in dry conditions. It is preferable to pack the product without moisture barriers of any kind. The shelf life of pasta is up to two years, less under humid conditions. "Typically a manufacturer won't have the product around more than about 120 days," says Jemison. "And there isn't an appreciable drop in quality or product degradation at the end of the shelf life." Says Wolgel: "Many people in the food industry and in the industrial segment like to have liners in pasta. From our standpoint, that's not a very good idea because it does not allow the pasta to breathe. Shrink-wrapping has the same problem. Although the pasta is dried, it continues to undergo evaporative water loss. Improper storage -- such as tight plastic liners, high humidity or heat -- may allow mold to form. The tendency of pasta to absorb or lose moisture also can result in short weights, according to Vermylen. "There is a problem with weight loss and with the weights and measures in various localities. I believe the FDA has just established a gray area for pasta, where it can have a 3% tolerance for moisture loss affecting the net weight," he relates. "Right now, if you pack pasta at 12.5% moisture and your target weight is 16 ounces, you might pack an additional one-quarter ounce to account for weight loss. But if the moisture goes down to 8% or 9%, you will be below the stated weight on the package." Other critical specifications for pasta products are shape and size. Several of these are defined in the standard of identity:Macaroni. Tube-shaped or cord-shaped, and between 0.11 and 0.27 inches in diameter.Spaghetti. Tube-shaped or cord-shaped, and between 0.06 and 0.11 inches in diameter.Vermicelli. Cord-shaped (not tubular), and no more than 0.06 inches in diameter. Other pasta shapes bear their traditional names: penne, rigatoni, spirals, farfalle (bow ties), radiatore (little radiators), and so on. The length of what are called long goods -- like spaghetti and lasagna -- range from 10 to 20 inches or more. The size can be reduced for a given application -- for example, to fit in a baby food jar. "Short goods are up to 3 inches long," Jemison says. "After that it becomes a problem to dry them properly." The formula usually does not change with the shape, except thinner shapes could require ingredients to strengthen the structure and improve the cooking characteristics. Also, an extremely thin shape might not be the ideal form for a macaroni formula containing tomato solids. "You are limited in wall thickness by both the process and the end use," notes Vermylen. "Pasta usually ranges from 0.020 inches for a very fine angel hair to about 0.060 inches for a very thick-walled product. If you try to go any thinner, you can't extrude the product and breakage becomes a problem. Any thicker and drying the product would be extremely difficult." Novelty shapes are popular for "kid-themed" or seasonal products. There is almost no limit to the possible shapes, but they must follow the same size constraints as other products. Also, the shape must be an outline format with spokes, similar at to a wagon wheel-shaped pasta, to give the product structure. The technology does not currently exist to mold solid, shapes like you would find in the candy or cookie industries.Using your noodle The physical characteristics of pasta vary for individual applications. The end use can dictate formulation, moisture, size and shape of the product. Some applications are more destructive to pasta than others. Retort conditions are the harshest. The steam table follows right behind. When pasta is subjected to long periods of cooking, it becomes starchy and soft. Two characteristics -- formulation and wall thickness -- can be altered to improve the finished quality. Adding higher protein levels via egg white or adding glyceryl monostearate is usually recommended for pasta destined for abuse. Additionally, the thicker the wall, the better the product can withstand abuse. Manufacturers of canned pasta products most often use uncooked pasta filled directly into the cans to minimize heat exposure, but this increases starchiness in the finished product. The moisture level of pasta can affect some dry-mix pasta products. If a high-moisture pasta is put in a package with a seasoning mix, the moisture can migrate out of the pasta into the seasoning, which is usually very hygroscopic. This can make the mix lump together or create moisture-related problems like accelerated rancidity, resulting in an unacceptable product and shortened shelf life. For this type of application, use a pasta with a moisture content of 8% or less. Quick-cooking or packaged mixes require an instant form of pasta. Historically, two technologies have been used for instant pasta. The Ramen, or fried noodle, is the Oriental method; freeze-drying is the European method. The term Ramen sometimes refers to a shape rather than the technology. Fried noodles typically use hydrogenated oils and many manufacturers add ingredients like MSG, so this is not always a desirable option from a labeling standpoint. Freeze-drying is very expensive and is generally available only from Europe. "About 25 years ago a major company came to us and asked us to develop an instant noodle," relates Wolgel. "Without getting into a lot of proprietary technology, what essentially happens is the pasta is made in a sheet and slit. Then it is pregelatinized. You have to pregelatinize to get any of these quick-cooking products. The process usually involves high-temperature steam." One pasta technology involves a flash evaporation step that causes the noodle to puff, resulting in better eating quality. That technology also can be used to produce quick-cooking pasta. "There you take a standard pasta extruder and use a different, more thin-walled die. This reduces the cook time," says Wolgel. "You next pass the pasta through a steamer and then through a conventional dryer. The result looks like conventional pasta, but acts more like an instant pasta. These are in the five- to six-minute cooking time range." Instant noodles require only boiling water for the product to rehydrate. Quick-cook noodles need boiling, but the time is drastically reduced -- to about half that needed for regular pasta. These types have less cooking tolerance less than conventional noodles. "The technology by which you make couscous is similar to the technology used for instant pasta," Wolgel adds. "It's pregelatinized using steam beds. To prepare it you add boiling water and let it sit for three minutes. From a development standpoint, you have the potential to make an interesting product. Couscous appeals to those looking for high nutrition and convenience and to the upscale market, but it is just a precooked pasta. There's some interest in mixing it with breadings or using it as an extender for vegetarian patties. There are a lot of possibilities, but it will take time for couscous to become mainstream." Filled pastas are becoming increasingly popular. This pasta uses the same ingredients as macaroni and noodles. The dough is sheeted, the filling deposited, and the dough is cut and sealed. Filled pastas can be dried or left at higher moistures for refrigerated or frozen products. The biggest opportunity to design a unique product lies with the filling, which can contain meat, cheese or vegetables. "You'll notice that manufacturers are getting quite fancy, using things like chicken, walnut, and exotic cheeses in the fillings," observes Vermylen. "Just regular filling like meat or cheese or spinach has almost become a commodity item like spaghetti." There are hundreds of variations in pasta shapes, sizes, formulation, processing and application, and pasta has a great nutritional profile. It goes well with a wide variety of products and flavors. Experimenting with all of these aspects open a broad range of "pasta-bilities."Standardized Macaroni and Noodle Products in the United States |
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