August 1, 1998

23 Min Read
Prepared Pasta and  Rice Dishes

What's typically easy to prepare, healthful, inexpensive and appeals to a wide variety of consumers? The answer lies in take-out establishments and throughout grocery shelves and freezers: prepared pasta and rice dishes. Convenience at the cash register requires a sizable amount of work in the lab to guarantee the finished product meets expectations.

Today's consumers want either packaged mixes they can cook and serve within minutes, or completely prepared products they can heat (or not), and eat on the spot. Though the concept is simple, the execution is anything but, due to the complex nature of the ingredients, processes and consumer requirements. Like the food pyramid, the base consists of grain-based products. And although pasta and rice alone are nutritious, as they say, variety - in the form of sauces and seasonings - is the spice of life.

Using the noodle

A number of dough-based products fall under the category of pasta, including noodles, macaroni and various specialty items, such as ravioli, gnocchi, couscous and ramen noodles. The word "noodle" often is used generically, but FDA has reserved this term as well as the term "macaroni" for 15 different categories defined by standards of identity. These are in 21 CFR, Sections 139.110 to 139.180, and include macaroni products ("regular," enriched, enriched with protein, milk, enriched and nonenriched nonfat milk, enriched and nonenriched vegetable, whole wheat, and wheat and soy) and noodles ("regular," enriched, enriched and nonenriched vegetable, and wheat and soy).

The standards allow noodles and macaroni formulated with semolina, durum flour, farina or flour. Durum wheat, a hard spring wheat, makes the best pasta. Durum semolina, a granular form (150 to 450 microns) of flour from the endosperm, produces the highest-quality pasta. It contains optimum proportions of two amino acids (gliadin and glutenin), which are essential for proper gluten development and natural pigments (xanthophyll, carotenoids) to make the typical amber-yellow color of premium pasta. Semolina imparts resistance to overcooking, cuts starchiness, and lends a firm bite and characteristic flavor. The higher the flour's ash content, the softer the texture and the grayer the color. Unenriched pasta usually contains 12% to 14% protein.

Egg noodles usually contain durum flour, which has a smaller particle size than semolina. The standards require 5.5% egg solids (whole egg, yolk or a combination) on a dry basis. Yolk produces a deep yellow color; the white's protein improves cooking quality and gives a firmer bite.

Macaroni consists of durum semolina and water, and any other ingredients listed in the standards. For instance, vegetable macaroni contains a minimum of 3% vegetable solids, but only tomato, spinach, beet and several others are allowed. Adding vegetables produces mainly color, little flavor and a loss in cooking quality.

For specialty markets or ethnic designs, certain pasta products contain rice, potato, buckwheat, quinoa, amaranth or other grains. Because of the lower protein content, the pasta is softer, loses more starch during cooking, and can be easily overcooked.

A typical dry packaged mix only requires cooking prior to serving, so standard pasta will suffice. However, pasta used for more severe applications, such as freezing, steam-table use or retorting, requires added strength. Long cook periods turn pasta starchy and unacceptably soft. Thick-walled pasta withstands severe conditions better than thinner shapes. For retort applications, most pasta goes uncooked into the can (this minimizes heat exposure). But this practice increases finished-product starchiness as the starch sloughs off during heating.

CFR also allows egg albumen, alginate and glyceryl monostearate in noodle and macaroni formulations to add process tolerance. The egg-white protein strengthens the network that holds the starch in place during cooking and gelatinization. Glyceryl monostearate complexes with amylose, forming insoluble helical structures that hold in the starch and decrease water absorption; this reduces starchiness and stickiness.

Although generally not included in macaroni and noodle standards, other ingredients may be added to pasta: fiber, herbs and spices, and other flavorings. Onion, celery, garlic and bay leaf are listed in the standards, though. Most additives, especially at high levels, can adversely affect the texture by reducing the protein level needed for a strong matrix. Also, hygroscopic ingredients can make drying to the target moisture difficult. Ingredients that provide visible particulates also can clog extruders.

Pasta is formed by extrusion, or sheeted and cut. Long goods - pasta such as spaghetti and lasagna - range from 10 to 20 in. or longer. Short goods are up to 3 in. long. Shapes such as bow ties require specialized equipment for cutting and bending.

Standard pasta is dried to approximately 12% moisture to ensure shelf stability. Some manufacturers use a traditional low-temperature process. Others dry at higher temperatures, which cuts the drying time, seems to improve the cooking quality and color, reduces the microbial load, inactivates flour enzymes, and increases its resistance to overcooking. The proper drying conditions depend on the pasta's geometry (shape, dimension, mass-to-surface ratio, etc.), with thinner products taking significantly less time to dry than thick-walled products. For refrigerated applications, pasta is dried to reduce moisture and may be steamed slightly before storing in gas-flushed packaging. The inert gas inhibits microbial growth, providing a shelf life of up to 12 weeks.

Precooked pasta is cooked in water near 98° to 99°C, or it can be prepared with superheated steam and humidity kept at saturation levels. Immediate cooling halts further cooking prior to final refrigeration, packing or freezing. Sauces or seasonings can be added, and the product can be frozen in a tunnel or a spiral freezer with cryogenic gas or conventional cold air to -18°C or lower.

When dry pasta is put into the same package as a seasoning mix, the pasta moisture can migrate to a hygroscopic seasoning, causing lumping or inducing other moisture-related problems. For this application, manufacturers typically specify a pasta moisture of 8% or less, depending on the application and mix formulation. Dried pasta can pick up moisture in humid conditions and lose moisture in dry conditions. Usually packaging without moisture barriers is preferred, since tight plastic liners, high humidity or heat can promote mold. The shelf life of pasta is up to two years - less under more humid conditions.

Improper drying can cause checking. The pasta surface case-hardens, trapping the moisture inside. Later, this moisture migrates to the surface, creating pressures that cause the pasta to crack. This can occur soon after drying, or much later, which will cause pasta to shatter when cooked.

Pick your pasta

The innumerable shapes and sizes of pasta make it difficult to decide what's best for a specific application. Several considerations influence the choice:

Labeling and product name. Several shapes are defined in the standard of identity: macaroni (tube- or cord-shaped with a diameter from 0.10 to 0.27 in.); spaghetti (tube- or cord-shaped with a diameter from 0.06 to 0.11 in.); vermicelli (cord-shaped, not tubular and with a diameter no more than 0.06 in.). Others are named for their traditional shapes: penne, rigatoni, orzo, farfalle (bow ties), radiatore (little radiators), etc. Italian pasta comes in more exotic shapes, such as spiral-shaped chiocciole or horn-shaped cornetti.

End use. The application greatly influences the shape and size used. Thicker-walled pasta needs an increased cook time, so it holds up better and is firmer. Delicate angel-hair pasta turns to mush in a retort or steam table, or if the consumer overshoots the cook time. A better option for code tolerance would be a thick-walled rigatoni. Plus, the traditional rigatoni shape can be modified to meet the rigors of handling, processing and packaging - it can be shrunk in size to facilitate a filling operation or lessen weight overruns.

Quick-cooking packaged mixes require instantized pasta, and several technologies have been developed. Instant pasta only requires boiling water for rehydration and would be used in an instant cup-type product. A ramen, or fried noodle, results in an oriental-style instant noodle. Another option is freeze-drying precooked noodles, but this is very expensive and not readily available in the United States. Another method uses steam to pregelatinize thin-walled pasta. This is then dried conventionally for a quick-cooking pasta (five to six minutes) or puffed, so it is instantized. This technique reduces cook tolerance.

Couscous, a type of instant pasta, is gaining popularity because of its use in Mediterranean cuisine. The small granules can be rehydrated with boiling water in three minutes to a fluffy, rice-like consistency. Like instant pasta, it requires a steaming step to pregelatinize the starch.

Gnocchi (potato dumplings) are formed from an extruded dough of precooked potato flour and/or potato flakes and soft wheat flour. Additional equipment can form surface ridges, and coat the gnocchi with rice flour to reduce sticking. They are typically manufactured as a refrigerated or frozen product, with a moisture content from 50% to 70%.

Filled pastas, such as ravioli and tortelleni, use the same dough ingredients as macaroni or egg noodles, but carry a wide variety of fillings, not just cheese or beef, but chicken and prosciutto or basil and walnuts. Ravioli dough is sheeted, the filling deposited and the dough is cut and sealed using stamping dies that produce single pieces or strips. Some equipment produces single dough sheets where the sheet is folded and pressed after the filling has been deposited. Others form double sheets, with the filling deposited on a bottom sheet, covered with the top sheet, then pressed, sealing the two sheets on the ravioli edges.

Tortellini is not stamped; forming machines fold a small pasta strip laterally over the filling, joining and sealing two opposite edges or pinching them. The classic tortellini shape is a ring, empty in the center, but the word "tortellini" also often refers to shapes without a space in the center such as capelletti. Tortellini are easily dried due to a small dimension and favorable weigh-to-surface ratio. Most filled pasta is left at higher moistures for a retorted, refrigerated or frozen product.

The rice is right

Unlike pasta, rice only comes in one general shape - rice-shaped. But that doesn't mean that rice-based dishes need to be boring or that they don't require much thought to design. This month's Culinary Connection offers some insight into this grain's versatility.

Thousands of rice varieties exist, but the three main types are categorized mainly on the basis of size and amylose content: long-grain, medium-grain and short-grain. When cooked, they yield different characteristics.

Long-grain rice. Highest in amylose (23% to 26%), long-grain cooks up dry and fluffy, with distinct grains three to four times longer than their width. Long-grain offers the best kernel integrity, and maintains uniform kernels after it is frozen and reheated. It retains moisture better than most other types of rice. Specific varieties have superior overcook and abuse resistance, and are recommended for canning applications. This variety also has the highest gelatinization temperature: 74°C.

Medium-grain rice. The kernels are two to three times longer than their width. A higher amylopectin content (18% to 26%) makes cooked medium grain soft and tender, and cling together.

Short-grain rice. A high amylopectin content and lower amylose content (15% to 20%), gives short-grain a tender, sticky, almost creamy texture.

Processing these rice varieties yields a wide range of characteristics that help determine which is best for a particular application. Most rice is milled, removing the outer bran. Brown rice retains the bran, giving it different characteristics from milled rice. In addition to the characteristic color and flavor, bran absorbs water at a slower rate than the starchy endosperm. This causes the bran layer to split irregularly so that the cooked grains look torn and misshapen. Slower water absorption also means that brown rice takes longer to cook than white rice, about 40 to 50 minutes as compared to 15 to 20 minutes for regular milled white rice. The unsaturated rice-bran oil is subject to rancidity, so brown rice has a shorter shelf life than milled white rice.

Unmilled rice may first be steamed, creating parboiled rice. The heat gelatinizes the starch, which reduces breakage and creates firmer, more separate grains. Parboiled rice requires a longer cook time than regular milled white rice (about 25 minutes) and also can absorb more water.

Quick-cook applications, requiring a six-to-eight-minute cook, can use rice processed to expand the kernel structure without precooking. This speeds penetration of water, and helps maintain the kernel integrity and flavor. "It doesn't have that precooked flavor and texture," says Don McCaskill, director, R&D, Riceland Foods, Inc., Stuttgart, AR. "It is actually less sticky than the rice it is produced from." According to Dean Oliver, Riceland's pilot plant coordinator, long-grain and medium-grain versions are available. Specialty rices also have been tested, and while no short-grain quick-cook rice is on the market, he doesn't see any reason "why it wouldn't be technically feasible." But he notes that reduced stickiness "might not be an advantage in a short-grain application."

Instantized rice rapidly absorbs boiling water, making it ready for consumption in several minutes. The process opens up the kernel structure for rapid hydration by completely precooking, then drying. The texture is often less firm and the appearance differs from that of regular rice. Freeze-drying rice gives the kernel a much more open structure, so it can be rehydrated in minutes without boiling.

"Over the years, the rice industry has considered anything that is five minutes or less cook time as instant - that might be different from other ingredients where the word 'instant' refers to something that you just add hot or boiling water and let sit," says McCaskill. "Generally, a cup-of-soup-type product would require a freeze-dried rice, which is fully cooked, then freeze-dried, or an oven-puffed rice. The latter has a bit of a toasted flavor and browning, but that might not be a problem in some applications."

In addition to rice type, the cooking method affects the finished product. "Risotto usually calls for Italian arborio rice, noted for its creamy, sauce-like character," says McCaskill. "We can basically achieve the same thing using a medium-grain rice variety produced here by following the same cooking technique, adding part of the water at a time, and continuing to stir it while cooking." Covering and cooking rice results in a steamed effect, and might keep less starch from leaching out.

Refrigerated or frozen products might call for individually quick-frozen rice. This saves the capital cost of in-plant rice cook-up, and more importantly, provides a free-flowing product for the filling operation. Otherwise, preparation and hydration of the rice can be done on most types of blanching or cooking equipment, including steam-jacketed kettles or auger-driven continuous cookers.

Long-grain parboiled is the rice of choice for frozen applications, says McCaskill. If the in-house cooking equipment is marginal in terms of cook time, he suggests quick-cook as the next best option. "Typically, for products that require reheating, you would intentionally undercook the rice during manufacturing," he suggests. "You would probably target a 65% moisture on the rice." Normal, fully cooked rice is about 70% to 73% moisture.

After cooking, the rice requires cooling prior to mixing with sauce or seasoning ingredients. Otherwise, if the rice is above its gelatinization temperature, the kernels continue absorbing water, softening their texture and changing the sauce's characteristics. "The gelatinization temperature is about 70°C for long-grain varieties, and usually a little lower for medium- and short-grained varieties," says Zack Nehus, research engineer at Riceland. "It would continue to absorb water until it turns to a paste. That's one of the problems seen in retorting rice."

Quick-freezing after adding the sauce to the mixture gives the sauce minimal time to penetrate the rice. Also, rice held above the freezing point might give up moisture as it undergoes starch retrogradation.

Flavor appeal

While the bulk of pasta and rice dishes consist of the carbohydrate base, it's the flavor system or sauce that differentiates the products and promotes their appeal. These can range from simple, dried-spice systems to technically challenging sauces prepared to withstand rigorous processing or usage requirements.

"Overall, the trend is for strong flavors," says Jennifer Morgan, senior food technologist, Heller Seasonings & Ingredients, Inc., Bedford Park, IL. "Hot is still popular, but the associated flavor profile changes. You can get hot Southwest or hot with peanut sauce for Thai food. Indian food is gaining popularity, and we may be seeing more African flavors."

The flavor inspiration can come from popular restaurants, recipes or collaboration with chefs, but according to Morgan: "One of the most challenging parts is to develop a sauce in the kitchen, and then change the culinary version into a dry blend at the bench."

One of the most important considerations is the composition of the flavor system. These will be combined with a carbohydrate base and, although these are typically bland, some contribute characteristic flavors, such as brown rice or filled pasta. Their starchiness might mask or otherwise alter the flavor delivery. Thin, delicate pastas are complemented by lighter-flavored sauces, while a thicker ziti can carry a heavier meat sauce.

Product designers face a wide variety of flavoring ingredients with which to work. For example, with spices, fresh, frozen, dried, extracts, oleoresins and flavors are all available. Some work better in a given application - it's obvious fresh or frozen products would not work in a dry mix. But other issues arise. Fresh spices and seasonings might vary in character or intensity, while oleoresins or other natural or synthetic flavors deliver consistent flavor, especially if volatility is an issue. For visual impact, particulates from a dried or fresh spice will be required, and the flavor then can be standardized with oleoresin.

"If you are cooking a product longer," says Morgan, "you're going to want to use oils and oleoresins. If we were putting together a garlic-basil seasoning for a flavored pasta noodle, oils would have a greater impact after they undergo the rigorous drying and after the consumer boils the product. In a quick-cook product, you want to consider how the consumer will cook the product. You need ingredients that will rehydrate fairly quickly and have some tolerance in case the consumer doesn't follow the directions on the package."

Vegetables and, in some cases, fruits, often enhance pasta and rice dishes. The same issues arise as with spices: flavor consistency vs. appearance. So, while actual fruit and vegetable particulates lend eye appeal, if the product requires a strong carrot flavor, it might be wise to formulate with added flavors.

Fruits and vegetables come in a variety of formats. These have distinctive properties that dictate their use. Dry mixes require low moisture for shelf stability. Air-dried products rehydrate in seven to 15 minutes in boiling water, but they often lack color and flavor. Freeze-dried products rehydrate quickly - from almost instantly to about three minutes - and present an excellent appearance. But they're expensive, fragile and lack flavor.
Intermediate products, like puffed vegetables, take about three to five minutes for rehydration. Piece size and temperature also affect the hydration rate of dried particulates; the larger the piece, or the lower the rehydration temperature, the longer the hydration takes. With a dry mix, the moisture level in the fruit or vegetable should match the total mix. However, too low a moisture might make the product brittle, and it could become too fragile to withstand filling and shipping. A higher-moisture, lower-water-activity piece, like an infused product, might be the answer.

Another potential problem with vegetable and fruit pieces is even dispersion. In a dry mix, a two-stage filling operation can solve the problem by keeping separate the large vegetable particulates and the finer seasonings. In a "wet" mix, balancing the particle size and matrix viscosity ensures even dispersion, as does properly designed agitation and filling.

Staying dry

One important feature for all dry-mix ingredients is how well they blend together and stay blended. When dry-blending powders and particulates for a seasoning or sauce mix, choosing ingredients with similar particle sizes and densities helps create a homogeneous blend and prevents stratification. Other homogeneity problems might occur due to ingredient properties, such as hygroscopicity, susceptibility to electrostatic charges, and adhesion due to physical geometry.

Often, the flavor system requires a high-bulk carrier - typically maltodextrins, whey or some other bland, inexpensive material. Or, if starch is required, it could play the role of flavor-dispersal agent. Standard carriers or bulking agents can even provide a degree of functionality by stabilizing the liquid, binding water, and affecting the finished product rheology.

"It's important to have flowability of your seasoning blend and/or between the seasoning and the pasta and rice," Morgan says. "That helps give an even distribution of flavor. I've seen seasoning packets with a solid mass, and not only is that unappealing to the consumer, it doesn't give the same flavor profile." Ingredients that might cause problems in this regard, according to Morgan, include hygroscopic ingredients, such as garlic powder, HVP, soy and Worchestershire powders.

Anticaking ingredients, such as tricalcium phosphate or silicates, might be required to keep products free-flowing, especially when they contain hygroscopic materials such as cheese powders, high DE maltodextrins, corn syrup solids or hydrolyzed vegetable protein. The FDA dictates the allowable level of chemical anticaking agents - 2% maximum for silicon dioxide, for example. Certain compounds promote dusting problems, while others might alleviate them. "You might not have flow problems on the bench, but that doesn't mean you won't get them later on," cautions Morgan. "You have to consider how the product is used, where it's going and what conditions it will be used under."

Saucy stabilizers

Many factors influence the design of sauces formulated for pasta and rice, but one of the most important is the stabilizer system used. In sauces, the most common stabilizer is modified starch, but depending on the system requirements, gums and occasionally proteins perform this function.

Starches. This economical carbohydrate exhibits a wide range of functional properties, depending on the source and on any physical or chemical alterations to the structure. Starches provide viscosity through gelatinization. As heat is applied, the starch molecule absorbs water and swells. The gelatinization temperature varies: High-amylose corn starch requires a relatively long period of high heat, while potato starch can gelatinize at temperatures below boiling.

Most sauces require cook-up starches. Instant products need starches that hydrate at hot, but not boiling, temperatures. Often, these use pregelatinized starch, a product heated to the gelatinization temperature, then redried. The particle morphology affects the rate and degree of rehydration.

The properties of a native starch depend on composition, and change with chemical modification, including acid modification, crosslinking and substitution. For example, amylopectin gives waxy corn starch a high level of clarity, while amylose-containing starches such as dent corn and tapioca provide opacity. Potato starch furnishes clarity without gloss. For products requiring freeze/thaw stability, a substituted starch is best. Crosslinking increases process tolerance to shear, low pH and high heat.

Gums. Sometimes, starch doesn't provide all the answers. Like starches, gums provide viscosity and texture, and can be used by themselves or in combination with starch to create certain effects. Depending on the gum and the level, they produce textures ranging from gel-like to smooth but nonpasty. Certain gums promote cling, give an added measure of heat or freeze/thaw stability or even enhance filling operations by exhibiting shear- or heat-thinning properties.

In addition to the specific texture and viscosity requirements, the dispersion method greatly affects gum selection. Some gums require high shear, making them difficult to hydrate in home or foodservice preparation. Others disperse with minimal mixing, such as a prehydrated guar. Without proper dispersion and hydration, a gum will not develop significant viscosity.

Proteins. Particularly in cream-type sauces, proteins can provide viscosity. However, they tend to be more expensive than other stabilizers. Because they exhibit both hydrophilic and hydrophobic properties, they not only bind water, but have emulsifying properties.

Choosing the right stabilizer requires outlining the product characteristics and process conditions. These influence how well each performs in a given application.

Process conditions: Mixing procedures and equipment, temperature and duration of exposure to heat, agitation speed and shear, pumping and filling viscosities.

Formulation attributes: pH, ions, solids (competition for hydration) and particulate suspension.

Finished product characteristics: Clarity or opacity, mouthfeel, cling, freeze/thaw stability, microwave or heat stability, and flavor delivery.

The big cheesy

Cheese is one of the most popular flavoring ingredients in the United States for rice or pasta dishes. "When you are formulating a dry mix, you're going to need something that is shelf-stable," says Tom Rieman, senior business marketing manager, Kraft Food Ingredients, Memphis, TN. "Because of that, people tend to gravitate toward the cheese powders, although some might use a wet cheese sauce in a pouch or a can for an upscale product, since they are more expensive. But they all start with the same raw materials for the most part."

Most cheese powders are spray-dried from a cheese slurry and they often contain whey, starch and other functional ingredients and fillers. Originally, manufacturers started with natural cheese with added phosphate. Now, many suppliers use process cheeses or "cheese" that might not meet its standard of identity, for cost savings, then blend to achieve consistency. Natural cheeses tend to contain annatto or turmeric for color, but many cheese powders use the FD&C colors for a bright orange appearance, lower cost and increased stability.

According to Rieman, the actual content of the cheese powder depends on label declaration requirements and price: "There is no standard of identity for a cheese sauce or a cheese powder." However, a specific company might require a particular level of cheese solids or a product that meets a "real" or "natural" label requirement. The actual cheese content can range from 0% to more than 97%. Low-cheese solids make a more economical product, so high-tech cheeses, flavor potentiators or flavors save on raw material costs. "At KFI, we use natural cheeses for cheese powders," explains Rieman. "So, to stay more competitive, we use our technology and understanding of cheese to create proprietary cheeses for making cheese powder. We build more flavor on the front end using cultures and curing processes that give better flavor development."

Most cheese powders do not supply functionality; they primarily add flavor. "For a standard box of mac and cheese, you are not really trying to make a sauce, you are just trying to coat the macaroni," notes Rieman. "You are adding butter or margarine and milk, and the starch from the pasta also makes a contribution. For a regular cheese sauce, most manufacturers are formulating a white sauce using starches and gums, and adding a high-flavor cheese powder for flavor. There's not a lot of functionality from the cheese powders, especially as you get into the high-flavored cheese powders, because you are using less and less."

How the flavor comes across may vary depending on the application and the production method. The materials, as well as the manufacturing method, dictate product flavor type and intensity. A spray-dried slurry of a combination of ingredients gives a different-flavored product than a dry-blended product in the same ratio.

"Using a higher-flavor cheese as the technology advanced allowed us to reduce the dairy solids, but we found that too much whey gives you a sweet product," says Rieman. "So we started using other carriers: maltodextrins, vegetable fat - as opposed to butterfat - because of the cost. And, in some cases, we do use butterfat, because of the flavor profile that delivers."

The fat content affects the flavor and the handling characteristics. More fat helps flavor carry-through, and improves mouthfeel, but it also can make the powder more difficult to handle and promotes lumping. Fat content ranges from about 14% in blended powders to 38% for reduced-fat cheese versions to about 50% in a regular spray-dried natural cheese and 65% for spray-dried natural cream cheese.

Cheese sauces also can be formulated from a slurry of natural cheese. In this case, the cheese protein, fat and solids provide body and mouthfeel as well as flavor. Emulsifiers, typically a phosphate, are required in a "wet" cheese sauce to tie the products together.

Although some consumers look at a simple box of macaroni and cheese as the ultimate treat, pasta and rice make the perfect starting point for an innumerable selection of carbohydrate-based dishes. Mixing together a little technology, creativity and ingenuity allows the product designer to combine all the elements to bring to the table exactly what the consumer wants.

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