May 1, 1996

33 Min Read
Side Dishes:  Not Just a Side Issue

Side Dishes:
Not Just a Side Issue
May 1996 -- Cover Story

By: Lynn A. Kuntz
Associate Editor*
*Editor since August 1996

  Throughout culinary history, side dishes have rounded out a meal, providing nutritional and economic value. But usually the meat or even the dessert received the lion's share of attention while the side dishes became little more than an afterthought. In some cases they became cliches - roast beef or chicken with mashed potatoes and gravy; hamburgers with french fries; and veal scaloppini with a side dish of spaghetti or mostaccioli. Most commercial side dishes were comprised of a bland starchy food, sometimes with a smattering of undistinguished sauce or seasoning, often accompanied by a plain vegetable. No one really got excited about them, but everyone would eat them.

  Now the focus has shifted subtly, but definitely. Side dishes have earned a little more respect. Food manufacturers and foodservice operators depend on side dishes to provide excitement and variety to their offerings. They have noted that their customers frequently base purchase decisions on the types, diversity and quality of side dishes.

  "The popularity of side dishes is definitely increasing," observes Julie Hayes, marketing manager, Basic Vegetable Products, Suisin, CA. "As Americans become more health conscious, they are moving away from typical 'meat' entrees toward a focus on vegetables and protein substitutes. Vegetables and side dishes are increasingly taking over the traditional role of meat as the focus of the meal, as evidenced by the growing presence of vegetarian entrees and lengthy side dish menus. Moreover, side dishes provide variety in tastes that many look for in their dining experience. With this in mind, consumers have become more experimental."

  Convenience and economics also drive consumer interest and, therefore, affect the formulation of these products. Few people have the leisure time to create elaborate meals This has led to a surge in "speed scratch" cooking, where speed and simplicity of preparation hold great appeal. Plus, consumers have discovered the ease of carryout and are looking for more than a bag of burgers or a bucket of fried chicken with french fries. In most cases they want products to resemble something prepared at home by some idealized "Mom" - that is, the products should be high quality, good tasting, and often fairly inexpensive.

  While all do not heed the call, most people recognize the importance of "healthy" eating when making food choices.

  "The Mediterranean diet, noted for contributing significantly to low rates of heart disease and for preventing certain types of cancers, appears to be affecting the prepared side dish market," says Lori Hicks, convenience blends development manager, research and development, Kerry Ingredients, Beloit, WI. "It has put a renewed emphasis on the primary staples of grains, including rice, as well as pasta and potatoes. Likewise, the move to down-sized entrees with more fish and small amounts of very lean meats has brought an accompanying move toward more upscale side dishes."

  Indeed, what one person considers a side dish would be accepted by another as a main dish. This is true of many forms of pasta, some rice combinations, and even the occasional "dressed up" baked potato.

  So, although the consumer readily accepted fairly simple, ordinary side dishes in the past, the increasing sophistication of the market requires increasing sophistication of the technology used to make side dishes more appealing to consumers today.

Handling with care

  The technical considerations have just as strong an impact on what goes into these products as the market factors. Side dishes crop up just about everywhere: on the supermarket shelf, in the produce section, in the freezer case, in the deli cabinet, or on the steam-table. Each of these requires different considerations in terms of product content, processing, handling and shelf life.

  The storage conditions greatly influence formulation. A side dish designed for extended room temperature storage falls into one of two main categories: a low moisture product that does not support microbial growth, or a high-moisture product rendered commercially sterile. Refrigerated products may approach the quality of Mom's home cooking, but have strict limits in terms of shelf life and safety. Frozen side dishes can often mimic "freshly prepared," but create major challenges in terms of freeze/thaw stability. Extended heating on steam-tables gives rise to other formulation headaches. Ingredients, processes and packaging used in each of these situations must be tailored to give the best results under the conditions the products encounter.

  "One of the hardest things to do technically is to make a product taste like it's been made from scratch," says Doug McCommins, West Coast sales director at Kerry Ingredients' Specialty Division. "The consumer doesn't care what the processor does as long as the result is quick and easy to make - but it's got to taste like scratch. For years, that's been one of the biggest hurdles, especially for dehydrated potatoes; they're readily perceived as processed food by consumers."

  • Dry mixes. A number of issues influence the formulation of side dishes in a dry mix format. The most obvious is moisture. The ingredients used must contain low levels of moisture, and all portions of the finished product must have a water activity below 0.6 to prevent microbial growth and spoilage. However, unless that water is chemically bound, it will migrate and equilibrate through the various ingredients. Regular milled rice or dried pasta typically have a fairly high moisture content - about 12%. If blended and packaged together with a lower moisture sauce or seasoning mix, moisture migration to the mix can affect shelf life. With hydrophilic ingredients such as cheese, this may result in caking and affect hydration during preparation.

      Moisture barriers prevent moisture migration from other ingredients, as well as from the air. Separate packaging can prevent moisture transfer between ingredients. Many dehydrated potato, pasta and rice products are packaged without any moisture barriers, so the moisture can increase in high-humidity situations and decrease in low humidity. Normally this does not hurt the product. However, product packed at the high end of the range may give up sufficient moisture under dry conditions to cause short weight packages. In a mix packaged without moisture barriers, using a low-moisture version of a product - a pasta with 6% moisture, for example - can minimize problems.

      When dry blending powders for a seasoning or sauce mix, it pays to keep a number of factors in mind. Mixing ingredients with similar particle sizes and densities helps create a homogeneous blend and prevents stratification. Some ingredients may have properties that hamper their incorporation into a mix, such as hygroscopicity, susceptibility to electrostatic charges, and adhesion due to physical properties such as shape.

      The rehydration requirements, especially the time and temperature range, influence the types of ingredients needed. For example, most dry mix side dishes have a cooking step and use cookup starches. Others need starches that hydrate at hot, but not boiling, temperatures.

  • Retort products. Some high moisture side dishes, especially vegetables and pasta, undergo retort processes to ensure commercial sterility. The extended exposure to heat may ensure product safety, but it usually has the opposite effect on quality. Flavor, texture and nutritional value often suffer. High temperatures accelerate vitamin C and thiamine loss and degrade many naturally occurring pigments.

      The heat treatment required for commercial sterilization of a particular product depends on the type and number of organisms present, pH, and presence of solutes such as sugar and salt. Also, the higher the temperature, the shorter the time required. The severity of the heat treatment depends on a number of critical factors, including the type of process and equipment, the size and shape of the container, the viscosity of the product, the amount and geometry of the particulates, and the headspace. Optimizing these to minimize the necessary heat treatment will help increase the quality of the finished product.

      Certain ingredients stand up better to high-heat processes. Carrots can take more heat than broccoli florets. For starch, cross-linking increases the heat stability; the more cross-linking, the more stable the starch. However, the same structure that makes the starch granule resistant to abuse also slows the swelling process during hydration. As a result, cross-linked starches tend to provide lower viscosity.

  • Refrigerated side dishes. Several years ago, refrigerated foods seemed destined for an early demise, but it appears that reports of the death of this category were premature. Fresh pasta has carved out a comfortable if not burgeoning niche, and one of the fastest growing food categories is fresh, prepared vegetables. Additionally, refrigeration has been the only viable option for many deli or foodservice products, especially chilled salads like coleslaw.

      The No. 1 concern for refrigerated products is shelf life - from both a quality and a safety perspective. Packaging technology has helped address many of the quality issues. Proper storage temperatures and atmospheres help preserve product quality. Most fresh produce must respire; therefore, packaging companies have developed gas permeable films to equilibrate the atmosphere in the package. Desiccants can absorb excess humidity where it could cause problems.

      Still, we also must focus on sanitation, handling and other safety issues to ensure that problems do not arise, especially once the product is out of the hands of the processor. Some pathogens can grow at refrigerated temperatures, and a low-acid, non-ionic, high moisture food provides an ideal medium.

  • Frozen products. In theory, freezing is an ideal method of preservation. Obviously it can't be used for a "fresh" salad, but it gives good results for products that normally would be cooked. In a side dish, the base and any sauce is usually precooked and any vegetable is blanched to inactive the enzymes. The product then requires minimal heating before consumption.

      The freezing points of different foods vary depending on the amount of free water present. Since most side dishes do not consist of a homogeneous mass, some portions freeze more quickly than others. As the water freezes, the concentration of electrolytes in the unfrozen portion of water increases. This can adversely affect colloidal structures - causing protein coagulation, for instance. It also can increase the concentration of reactive substances, which may promote undesirable reactions such as fat oxidation.

      Rapid freezing forms smaller ice crystals, and smaller ice crystals usually mean less damage. However, even slight temperature fluctuations during frozen storage or handling cause thawing and refreezing. The more freeze/thaw cycles a product undergoes, the larger the ice crystals become. The part of the side dish nearest the surface of a package will encounter the most frequent temperature changes.

      As the water in a product thaws and refreezes, the crystal formation ruptures physical structures, promoting water migration, syneresis, emulsion breakdown, and loss of viscosity. Several cycles often cause significant deterioration in flavor and texture. Six to 10 such cycles are not uncommon for a typical frozen product during handling and storage. Certain stabilizers, including hydroxypropylated starches and cellulose gums, provide freeze/thaw stability.

  • Steam-tables. Side dishes designed for foodservice are often prepared in large batches and held for long periods of time, typically at 160° to 200°F. This practice creates a number of technical challenges. The product quality must remain acceptable, microbial problems must be avoided, and functional ingredients must maintain their performance. Ingredients must keep their particle identity, and the color must remain unaffected by Maillard reactions or caramelization.

      To maintain viscosity or to prevent emulsions from breaking down, any stabilizer selected must be resistant to breakdown over long periods of time at relatively high temperatures. Again, this means cross-linked starches and heat-resistant gums. However, no stabilizer system will stop water loss from evaporation.

      After identifying the conditions the ingredients and final product will encounter on their way to the plate, it's time to look at some of the ingredient options. The typical serving size for a side dish is 1/2 cup, but there are many possibilities for the content. Usually these products have a grain or vegetable base, and often they contain a seasoning or sauce. The top side dishes in America are potatoes, rice and pasta. While space doesn't allow the discussion of all the ingredients used, we can take a look at the alternatives in some of the more common categories.

    The rice stuff

      Although the American public is experimenting with some forms of exotic grains in side dishes - such as kasha (roasted buckwheat), millet, quinoa, kamut and amaranth - the most common and widely consumed whole grain is rice. According to the USA Rice Council, last year each American consumed over 20 lbs. (both directly and as a food ingredient) and that figure continues to increase.

      Two reasons account for the popularity of rice: It is a staple in many popular ethnic and regional cuisines; and it provides a number of nutritional advantages. Rice contains little fat or sodium. White rice has only about 103 calories per 1/2-cup serving, and it rarely triggers allergic reactions.

      "As food processors and consumers become more aware of the different types of rice that are available, we see more creative things occurring," says Keith Hargrove, director of technology, Farmers Rice Cooperative, Sacramento, CA. "We have basic parboiled rice for steam tables, and instant and quick-cooking rice for convenience mixes. Manufacturers have to understand the characteristics of the rice and how they relate to the process and the end product desired. There are three broad ranges of rice: short, medium and long grain. But within these categories, you still have a wide range of characteristics available due to the processing used."

      Thousands of varieties of rice exist, but the types that are most often commercially grown and used in the United States fall into three general classifications based on their size: long, medium and short grain. Each of these also exhibits certain textural characteristics based on starch composition. Long grain contains a high level of amylose, which causes the rice grains to cook up separate and fluffy. This is the type most widely used in this country as a prepared rice product. Medium and short grain types have increasing levels of amylopectin, which more readily forms a gel with water, giving these types a softer, sticky texture. This is preferred for many Oriental cuisines. Short grain rice absorbs more water than the longer types. Arborio, a medium grain rice, is used in Italian risottos. Glutinous, or waxy, rices are used for sticky products such as sushi.

      Other specialty rices appear in side dishes. These are usually known as aromatic rices because they contain high concentrations of 2-acetyl 1-pyrroline, the compound that characterizes the flavor of popcorn and nuts. A limited amount of aromatic rice is grown domestically, mainly Della (a cross between Basmati and American long grain) and Jasmine types. Jasmine, often found in Thai foods, has a slightly sweet flavor. Its size is similar to long grain, but the texture more closely matches medium grain. Basmati is a long grain aromatic that is typically associated with Indian cuisine, and some domestically produced sources do exist, according to Hargrove. Wild rice is not actually a member of the rice family; it comes from a type of grass native to northern United States and Canada.

      "The main rice varieties grown in the U.S. are by and large developed by the USDA," says John Kendall, director of process development, Riviana Rice, Houston. "Their goal is to make certain these varieties are as close as possible to the existing varieties, so there's not a lot of diversity. Some companies produce specialty products, things like Arborio and the aromatics, but that tends to be a captive, niche market. And usually the climate in California is much more favorable for growing those kinds of rice than here."

      Most rice is milled - that is, the outer bran has been mechanically removed. With brown rice, the bran remains. Intact bran layers do not absorb water as readily as the starchy endosperm does. This results in splitting of the bran layer, so cooked brown rice tends to look torn and misshapen.

      "The brown rice category is growing rather rapidly, although I'm not sure that's reflected as much in the side dish category," observes Hargrove. "Using conventional brown rice in that category is a bit of a hindrance because of the greater cook time and shorter shelf life. However, the nutritional advantages are a positive attribute. There are high quality instant versions being manufactured."

      Because rice bran oil contains a fairly high level of unsaturated fatty acids, it is susceptible to oxidative rancidity. However, despite the level of unsaturation, researchers have found that rice bran oil, or rather a component called oryzanol, appears to block the formation of LDL cholesterol. The bran also contains from 20% to 30% dietary fiber, which also has been linked to reduced LDL cholesterol.

      Both brown and white rice can be parboiled. Prior to removing the husk or bran, the rice is soaked, steamed and dried. This forces some of the vitamins in the bran into the endosperm and gelatinizes the starch, producing fluffy, less sticky kernels. This product is harder and less prone to breakage. The kernel integrity of regular long grain, milled rice falls between the medium grain and the parboiled long grain. From a quality standpoint, an intact grain is desirable. Broken pieces are often ground for meal or flour, although one product on the market called Rizcous is sold in tiny chunks that mimic the appearance of couscous, a Moroccan pasta.

      "Long grain, parboiled rice offers the best in terms of kernel integrity and gives nice, uniform kernels after it is frozen and reheated. It retains moisture better than most other types of rice," says Don McCaskill, manager of rice research and development, Riceland Foods Inc., Stuttgard, AR.

      Milled white rice contains about 12% to 14% moisture and takes 20 minutes to cook. Brown rice takes about 40 minutes. To produce forms that cook more quickly, both white and brown rice can be precooked and then dehydrated. During the process some of the flavor may be leached out, and the kernel appearance and texture differs from that of regular rice.

      Different forms and process variations result in different rehydration times. Instant rices are ready to eat in five minutes, and the initial moisture levels are a few percentage points lower than milled. Other proprietary processes also are used to open the texture and speed hydration without the same level of flavor loss and change in texture. Rice can be freeze-dried for side dishes that require almost instant hydration.

      Rice used in frozen side dishes must be precooked before freezing. Normally regular or parboiled rice is used. It should be cooled quickly to maintain the optimum texture. When adding sauce, the temperature of rice should be below the gelatinization point to minimize moisture absorption from the sauce. Quick freezing also gives the sauce less time to penetrate the rice.

      "Aside from stickiness, rice is a pretty foolproof ingredient," says Kendall. "For example, the only notable effect from pH is that you may get some whitening at an acidic pH. While you can get some sloughing off of starch from the surface at a pH lower than 5, in a formulated product you wouldn't even notice it. There's no organoleptic or visual change. even in a low-acid product. But there are process considerations. For example, excessive heat during processing can change the color to yellow or amber. A low moisture product may be susceptible to checking with dramatic temperature changes. Instantized rice can be susceptible to breakage in pneumatic systems. But these are pretty extreme cases."

      Holding rice at refrigerated or higher temperatures can promote starch retrogradation, and the rice may actually give off free liquid. Higher levels of amylopectin give rice more resistance to starch retrogradation. Rices that are high in amylopectin (short and medium grain) also tend to absorb less moisture over time.

      When rice undergoes a retort process it may be added cooked or uncooked. "Precooking rice in a retort operation is not always necessary," says McCaskill. "Often it's done to change the density of the rice so it doesn't settle out and so it remains uniformly mixed."

    Many "pasta-bilities"

      Last year, reports surfaced that eating pasta causes the body to produce excessive insulin which, in turn, creates rapid weight gain and all the associated health risks. However, cooler (and wiser) heads prevailed and pasta is back on the list of "good" foods. That's good news not only for consumers, but for product designers. Pasta can be the starting point for many side dishes, from all American macaroni and cheese to more exotic versions like couscous.

      The term 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, so these terms must be used with care.

      The two main categories defined by the FDA are macaroni and egg noodles. The standards of identity allow these products to be made with semolina, durum flour farina or flour, but durum wheat makes the best quality. Durum semolina produces pasta with a characteristic amber yellow color. It also imparts resistance to overcooking, reduces starchiness, gives a firm bite, and creates a characteristic, almost nutty flavor. Adding other kinds of hard spring wheat produces a paler color, a softer bite, and less resistance to overcooking. Egg noodles are generally made with a finer granulation durum wheat product, durum flour. An egg noodle contains 5.5% egg solids on a dry basis, using whole egg, egg yolk, or any combination of the two.

      In addition to these products, some ingredients termed pasta contain grains other than wheat, such as rice, buckwheat, quinoa and amaranth. These are generally regarded as specialty products destined for health food markets, medical or nonallergenic diets, or various ethnic products. Because these grains contain a lower level of protein than durum wheat, they tend to be softer and lose more starch during cooking.

      Most semolina and durum wheat used in the United States is enriched with the B vitamins and now, folate. The Code of Federal Regulations also allows added iron at a level of 16.5 mg per pound and added calcium at a level of up to 625 mg per pound in macaroni and noodle products. Noodles may contain vitamin D. Protein, generally soy protein or egg white, is allowed. The protein level of unenriched pasta ranges from approximately 12% to 14%.

      Adding egg albumen or other protein not only increases the nutritional profile, it strengthens the network that retains the starch during cooking and gelatinization. The standards of identity allow the addition of alginate and glyceryl monostearate to strengthen the pasta for severe process conditions. Glyceryl monostearate complexes with the amylose to form insoluble helical structures that retain the starch and minimize water absorption. Alginate is useful for steam-table applications. Carrageenan can be added to pasta that contains nonfat milk. Disodium phosphate may be added to speed cooking.

      Fiber and flavorings such as herbs and spices can be added to pasta. Technically, most of these ingredients are not included in the standards of identity for macaroni and noodles, with the exception of onion, celery, garlic and bay leaf. The standards specifically do not allow artificial colors, artificial flavors, artificial sweeteners, chemical preservatives or starch. Vegetable macaroni must contain a minimum of 3% vegetable solids. However, only tomato, spinach, beet and several others meet the standard of identity for this product. In most cases, especially in dried pasta, the main contribution of added vegetables, spices and flavoring is for appearance.

      "The American Italian Pasta Co. has done a lot of work on retail or foodservice pasta, adding ingredients like porcini mushrooms," comments Sanford Wolgel, Ph.D., industrial sales, Conte Luna Foods, Philadelphia. "They are very nice products, but packaged-product manufacturers are usually not too interested. For them, the flavor carry through from pasta is not a big issue; they want the flavor to come from the whole system, including sauces. In most cases they are just looking at added ingredients for the perceived added value and visual effects. The AIPC product is targeting the retail or foodservice market that may be using minimal sauce so flavor carry through will be more important. But to achieve that, they need a much more sophisticated flavor system - things like encapsulated flavors."

      Dried, shelf-stable pasta contains approximately 12% water. Frozen pasta usually has about 28% moisture. To increase the shelf life of retail refrigerated pastas to up to 12 weeks, the product is quickly dried to reduce the moisture and then sometimes steamed slightly and put into gas flushed packaging.

      Pasta is extruded or die-cut to the desired shape. The standard of identity defines several shapes and sizes, including macaroni, spaghetti and vermicelIi. Other forms are named for their traditional shapes: penne, rigatoni, spirals, fusilli, farfalle (bow ties), radiatore (little radiators), etc. Novelty shapes formed to represent a cartoon character or even seasonal motifs can come from specially designed dies. Long goods such as spaghetti are available in custom lengths to fir specific applications.

      "The big shape right now is bow ties," says Wolgel. "People want to differentiate their products; they are trying to add some perceived value by experimenting with different shapes, flavors and ethnic products."

      Both the retort process and the steam-table have adverse effects on pasta. When subjected to long periods of cooking, the product becomes starchy and soft. This can be addressed by varying the shape, size and formulation. Adding uncooked pasta filled directly into cans minimizes heat exposure, but it also increases the starchiness in the product.  "Wall thickness and shape affect how well the pasta holds up. Smaller, heavier walled pieces work much better in retort application," points out Robert Vermylen, vice president of A. Zerega's Sons Inc., Fair Lawn, NJ. "Using 100% durum semolina or durum flour helps keep the pasta firm and reduces starchiness in the finished product. Adding egg albumen and glyceryl monostearate, which are allowed by the Federal Standards of Identity in pasta, provides additional benefits."

      Retort pasta should rehydrate more slowly than that designed for home use in order to reduce overcooking. Increasing the wall thickness and adding functional ingredients slows the cooking process. The insoluble network formed by egg albumen forms a water insoluble network. This entraps the starch granules, slowing down gelatinization. Glyceryl monostearate complexes with the amylose and minimizes starch migration to the surface, decreasing water absorption after cooking.

      To provide consumer convenience, many packaged side dishes use pastas in quick-cooking or instant form. The traditional forms are Ramen, or fried noodles (the Oriental method), and freeze drying (the European method). The term Ramen sometimes refers to a shape rather than the actual process used.

      "Cooking pasta entails two separate processes: starch hydration and protein denaturation," says Wolgel. "The structure of pasta is such that the starch granules are embedded in a protein matrix. As dry pasta is exposed to heat and water, the hydration of the starch occurs with gelatinization and the starch granules swell. At the same time, the heat denatures the protein. These two reactions need to be balanced to produce pasta with an acceptable taste and texture. The starch must stay embedded in the protein matrix and not slough off, and the protein must not completely lose it's integrity."

      Wolgel continues, "Technologies for altering the cooking characteristics of pasta have concentrated on the hydration/gelatinization phase. Pregelatinization is usually accomplished directly after extrusion or sheet formation with steam. To dry this type of pasta, a variety of proprietary technologies have been developed, including freeze-drying and specialized dryers."

      Instant noodles usually need only boiling water for rehydration, which takes about 90 seconds. Quick-cook noodles require a period of boiling, but compared to regular pasta the time is drastically reduced, about five to seven minutes. The cook tolerance on these types is less than conventional noodles.

      Couscous, which originated in the Mediterranean, is a pregelatinized form of pasta most often made of durum wheat and water. It also can be made with pearl millet or corn. It frequently appears in Moroccan dishes. To make couscous, the wheat is mixed with water, then the mixture is formed into small granules, steam-cooked, and dried. The finished granules are sorted by size into coarse, medium and fine grades. Americans seem to show a preference for medium grade. The coarse grade withstands retort conditions.

      This process yields precooked particles that can be reconstituted with hot or boiling water, or steamed, which is the traditional method. After cooking, couscous triples in size and resembles small fluffy grains, similar to rice. The cooked couscous should absorb sauce, resulting in additional swelling, but still maintain particle integrity. The traditional way to eat it is with a spicy stew, but because the product is bland it blends well with many flavorings.

      Pasta designed for microwave cooking needs thinner walls to hydrate more quickly. Reduction of the wall thickness increases fragility, so egg albumen is often added. In addition, disodium phosphate in the pasta formulation increases hydration rates and reduces cooking time.

    Spud wiser

      The country's No. 1 vegetable is the potato, served as french fries. It also makes a great main ingredient for a side dish. Most of us are familiar with meat and potatoes, but potato renditions go way beyond the mashed version.

      Most commercial potato varieties grown in the United States have white flesh and are classified according to their skin color: white, red or russet. The most notable exception is a yellow-skinned and - fleshed variety known as Yukon Gold. The characteristics of these different types of potatoes determine their appropriate use.

      Red-skinned potatoes contain a low level of moisture and a high level of sugar. This type works well in boiled applications, such as canning and prepared salads.

      Most french fries, hash browns, and even potato chips come from russet potatoes. Russets also are frequently used for dehydrated flakes and slices. This variety has a long cylindric shape that can be cut into long french fries. The medium moisture content (approximately 79% to 80%) minimizes oil absorption during frying and gives the desired texture in the finished product. The low level of reducing sugars minimizes discoloration during frying.

      The specific characteristics of a particular crop or variety of potatoes affect their usage. The most important factors include size and shape, defects, solid matter, and specific gravity. While these generally fall into certain ranges within a given variety, they may vary due to crop conditions, maturity, storage and handling.

      To get the desired size for french fries, a long thin tuber is needed. The standard size for thin cut strips is 3 inches. Processors use both trim and undersized potatoes for other products such as hash browns or dehydrated flakes. For peeled products, a high surface-to-weight ratio, deep eyes, and odd shapes such as knobs increase the amount of trim and, therefore, the waste.

      The potato processor's main goal is to maximize the amount of high quality product," says John Ojala, Ph.D., extension potato specialist, at the University of Idaho, Idaho Falls, Research and Extension Center. "Low quality material either gets a price discount or gets discarded. For a typical french fry plant, a 45% to 50% recovery rate is typical."

      Certain defects also affect the yield. These include discolorations due to disease or composition, greening and bruising. These are either hand-trimmed or mechanically sorted.

      "Anything that materially detracts from the appearance is a concern," says Ojala. "However, from a taste or nutrition standpoint something that affects the appearance is generally not a problem. A defect may be unsightly, but it won't hurt you if you eat it - even the green on a potato. When the sun contacts a tuber, it produces chlorophyll and that penetrates into the flesh. However, these cells also accumulate glycol alkaloids and that can cause bitterness. But to make someone physically ill, well, you couldn't physically consume that many."

      The specific gravity of commercial potatoes usually falls in the range of 1.058 to 1.105, according to Ojala. This corresponds to about 15% to 25% dry matter, but the exact relationships depend on the variety. Approximately 90% of the dry matter is carbohydrates, and about 85% of that is starch. For french fries, the specific gravity determines the finished product texture and appearance, recovery rate, oil usage, and amount of frying required. Potatoes with a low specific gravity require a longer fry time to bring them to the target moisture. Specific gravity also can be an indication of the level of reducing sugars.

      When reducing sugars in potatoes encounter heat, especially the high heat used for frying, it creates Maillard browning. Immature potatoes have high levels of sucrose and glucose. The concentrations depend on the particular variety and can rise during storage. For frying, ideally the sucrose level should be less than 1.5 mg/g and the glucose level should be under 0.035 mg/g.

      Fresh and frozen potatoes are also subject to enzymatic browning. This can be inactivated by blanching or by quick processing of fried potatoes after cutting. For applications that require cut and peeled potatoes to be held before cooking, sulfite treatment, usually sodium bisulfite, prevents the enzymatic discoloration. Other compounds such as ascorbic acid, cysteine, glutathione and sodium thioglycolate also can lessen the problem.

      Frozen potatoes used to come mainly in the form of french fries or some other fried product. However, demand for healthier alternatives and products better suited for microwave applications has led to the development of commercial IQF and roasted varieties.

      "Roasting of potatoes is done with a dry-heat oven," says Don Smith, vice president, marketing, Northland Frozen Foods, West Chester, OH. "That activates the chemical pyrazine, the compound responsible for the odor associated with roasted potatoes. Roasting case-hardens the surface and removes the excess moisture. When you microwave the potato, it doesn't have a mushy texture. The product remains firm, and because of the case-hardening, it remains stable in a sauce environment. We can make a high- or low-solids product, so you can have a creamier or drier product. The moisture range for a cooked product is between 60% to 75%."

    Extra extras

      Other ingredients, such as vegetables and beans, can be considered side dishes in their own right. And they, along with other components such as spices and flavorings, can dress up a base.

      Vegetables can give a product a healthful connotation, especially as more studies link their consumption to disease prevention, particularly cancer. When used as a side dish, the serving size of vegetables should be approximately 1/2 cup. Lesser amounts are often added to other side dishes to enhance eye appeal and flavor.

      Depending on the particular application, vegetables can be used in fresh, frozen or dehydrated forms. Raw vegetables contain enzymes that promote proteolysis, oxidation and browning, and other undesirable reactions. While they are most active at temperatures near or above room temperature, these reactions still occur when the vegetables are frozen. The enzymes can be inactivated by blanching - generally at 200°F for approximately two minutes. Often, processed vegetables go through heating sufficient to inactivate the enzyme without a special step, such as cooking or retorting. To preserve the texture, any blanching should be minimal, just enough to ensure the enzymatic inactivation. Certain agents, such as ascorbic acid, may prevent oxidative browning and preserve a fresh appearance.

      A number of factors can influence the type and specifications of the vegetable used. For frozen applications, size is often an issue (will that chunk fit in the package?). Also, some vegetables, such as zucchini, can exude a significant amount of moisture, so they must be combined with an absorbent component, such as rice.

      Dehydrated vegetables come in many varieties with differing properties: air-dried, freeze-dried, air/ freeze-dried, puffed and infused. While they are primarily used in dry mixes, they can be used in other applications. However, dehydration can result in significant losses in flavor, texture and color when compared to fresh. The degree depends on the process used and the type of vegetable. For example, carrots make a better dehydrated product than green peppers.

      "Dehydrated vegetables, unlike fresh vegetables, offer the convenience of ready-to-use vegetables precut in desired sizes," says Hayes. "They do not have waste and, unlike frozen vegetables, they have no special storage requirements."

      The rehydration rate often influences the selection of a specific product. Air-dried products rehydrate slowly - seven to 15 minutes in boiling water, depending on the vegetable. Freeze-dried products rehydrate quickly, from almost instantly to about three minutes. Intermediate products like puffed vegetables take about three to five minutes. Reducing temperatures below 190°F extends the rehydration time. Size also influences the hydration rate; the larger the piece, the longer the hydration.

      Contrary to popular belief, freeze-drying does not make the best product. In addition to the expense, the process itself drives off much of the flavor. It produces open cells, which promotes oxidation and color fading. Packaging must provide an effective oxygen barrier or freeze dried vegetables deteriorate rapidly.

      In a dry mix, the rehydration rate should fall in line with the other ingredients. Rehydration rate is a function of the size, the process, and the moisture level. If the moisture is too low, the piece may become brittle. If too high, it will accelerate deterioration. Less moisture migration occurs at lower water activities, so an infused piece can actually have a higher moisture content than other types without creating problems.

      Dried beans, or legumes, also can serve either as the base or an accent. Many varieties and products are available - everything from lentils to chickpeas to the very popular black bean and the not-so-popular (at least in my house) lima bean. We will take a more in-depth look at legumes in next month's issue of Food Product Design.

      Beans are probably the ideal retort product because they are one of the few that improve with the long exposure to heat. They even retain a relatively high level of vitamins through the cooking process. However, the same properties that make them ideal for long periods of heat make them ill-suited for convenience foods. Yet, there are instantized versions available. As with rice and pasta, the beans are first precooked and then dried, either conventionally or with freeze-drying. They will then rehydrate in minutes instead of the normal times of over an hour.

      From a nutritional standpoint, beans may be an appealing choice. They are relatively high in protein, although they may be lacking in one or more essential amino acids. They contain high levels of mainly soluble fiber - about 7 grams per cup of cooked beans.

      Spices are often an intrinsic part of a side dish formulation. They add flavor, and certain combinations lend an ethnic cache to the various bases. As appealing as they may be from a culinary standpoint, fresh and even dehydrated spices are not always best. Oleoresins and extracts provide better consistency in terms of flavor. If particulates are needed for visual appeal, then it is time to turn to a fresh, frozen or dehydrated version. From a flavor standpoint, though, fresh products typically have volatility issues, especially under high-heat conditions.

      "The side dish category has not been too experimental in terms of new flavors; they are usually well established before making it into a side dish," says McCommins. "However, new ideas may be emerging. There's a growing interest in using different strong flavored herbs such as basil, thyme and rosemary on potatoes. Cheese is always well accepted. We've recently developed a dramatic way to add visual and flavor impact, a shelf-stable flavored bit. These can be added to potato shreds to look like melted cheese and add flavor impact.

      "If you offer something unique - a garlic-flavored mashed potato - people get excited about the meal," he adds. "However, consumers still want comfort foods. And when foodservice operators test new flavors for potatoes, two types remain consumer favorites: scalloped and au gratin."

      The choices for ingredients for side dishes encompass a wide spectrum of tastes and functionality. Some categories that we have not even mentioned can improve the flavor, texture and appearance. The important thing to remember is that whatever the ingredients and whatever the form, the ideal formulation can take a side dish from being a bit player to having a starring role on the plate.

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