Vegging Out with Analogs

July 2001

By Suanne J. Klahorst
Contributing Editor

Health messages are powerful food for thought when persuading people to reconsider their dietary choices. Low-fat vegetarian diets are touted by some as not only the solution to reducing the risk of heart attack and cancer, but as a means of ending world hunger and preserving livestock and land management. For many, these diets include meat analogs as a protein source, many from soy, but some running the ingredient gamut from all-vegetable to those containing dairy and egg.

No matter what the philosophy behind the meatless-meal trend, it appears to be on the rise. Last year, Atlanta-based HealthFocus reported a study of 2,000 U.S. grocery shoppers that found that 22% buy meat substitutes, up from 7% in 1992. This increasing awareness has led to increasing innovation in the development of a range of meatless products, not just burgers, but everything from ham to hotdogs.

Good soy
In 1770, in London, Ben Franklin had the foresight to recognize soybeans as a “food of the future” and sent some beans to a Pennsylvanian farmer. It took two centuries and more than a few scientific advances, but Ben would be proud to see the contribution the Asian bean makes to nutrition and functionality in today’s processed foods.

A major U.S. field crop, soybeans always have been an excellent option for animal feed. In 1998, humans consumed just 3% of the soybean crop. However, ongoing health research and education has convinced more Americans to eat cow feed, rather than cows, resulting in an increase in human soy consumption.

Thirty million Americans claim to eliminate the animal link in the food chain, and go straight to plant sources for their protein, citing health, social responsibility, and ethical and religious beliefs as their main incentives. In addition, aging baby-boomers are interested in a reduction in dietary cholesterol and saturated fats. One-third of teenagers have experimented with vegetarianism. And for children — among whom obesity recently has become endemic — soy-food manufacturers offer low-fat entrées that consist entirely of soy protein. This has become possible recently, because the USDA has revised regulations that limited soy content to a maximum of 30% of the total grams of protein in a school meal.

According to a marketing report, entitled “The U.S. Soy-Based Alternatives Market,” by Aninditta Savitry, research analyst, Frost and Sullivan, San Antonio, TX, 76% of consumers are now aware of soy’s health benefits. The report estimates the purchase of soy-based products in 2000 at $622 million, with a 38% growth rate. Savitry’s review reveals that soy products are no different than other food products when it comes to establishing customer loyalty. They require excellent taste and flavor, brand equity, packaging innovation and convenience to succeed.

The success of soy- as well as wheat-based meat analogs is due largely to the development of technologies that provide the consumer with good-tasting alternatives without sacrificing their preferences for savory flavor and texture.

Texturizing taste
The development of texturization was a valuable engineering innovation that duplicates the appearance and chew of cooked meat products. Most forms of texturization today are accomplished by screw extrusion through a die that determines the final end product. Variations in the final product’s texture are achieved by changing temperature, pressure, moisture and mechanical force. The mechanical force is transformed into heat energy, which serves to plasticize the product and produce a texturizing “melt.” The heat also cooks the product and ensures microbiological quality. Depending on how the material is extruded and then cut, final shape options include chunks, granules, ropes, flakes or patties.

Early screw extruders had single screws and later technologies introduced twin-screw extruders, such as the one introduced this year by Clextral, Tampa, FL, developed with Protial, Angers, France. Clextral’s twin-screw extruder creates fiberized protein products with realistic meat texture, taste and mouthfeel. Prior to metering the vegetable-protein bases to the extruder, the raw materials are mixed to obtain a smooth blend. The extruder feeds and compresses the ingredient mass to a die that is cooled, and the change in temperature between the product and the die fiberizes the texture. The product can be brine-cooled with a solution including salt, color, flavoring or vitamin fortification before packaging. Clextral’s turnkey production system has a capacity of 200 kg per hour.

A wide range of physical characteristics can be achieved in the extrusion process due to the infinite number of protein/feed combinations available. Extruded products range from soy flours, soy concentrates and soy protein isolates, as well as blends of protein from different sources, such as the popular wheat and soy combination. Final products can simulate cooked muscle in many forms; they exhibit longitudinal or lateral fibration, surface appearances ranging from smooth to rough, a range of possible colors, and textures from soft to firm and elastic.

Many exclusive proprietary technologies have been developed. For example, Archer Daniels Midland Company (ADM), Decatur, IL, pioneered the first texturized vegetable protein® (TVP). According to Russ Egbert, director of protein research applications, at the company, “combining soy proteins with starches and other powdered proteins, such as wheat gluten, produces textured products that can be used to simulate ground meat, chunks and strips. Textured soy proteins are able to withstand retorting and can be used in canned applications.”

Midwest Grain Products, Atchison, KS, introduced textured protein from wheat gluten. The dry, textured product, when hydrated, looks and feels like meat due to a fibrous structure that can be adapted to mimic the look and texture of beef, chicken, pork or fish. The bland flavor profile and light color make it well-suited for lighter-colored analogs, such as chicken, and added colors can change its appearance to a darker variety. It is available in a variety of particle sizes and meat-like colors with a protein content of approximately 60% to 65%.
The number and types of technologies that product developers have access to for designing vegetarian entrées are daunting at first glance. Short of defining all the burger-building construction materials available, the architecture can be simplified to three major types of ingredients: proteins, binders and flavors. Plant protein can be obtained from a variety of sources, but today’s vegetarian entrées rely mostly on soy and wheat derivatives to provide the protein matrix.

Tempeh and tofu too
Tofu-based products are some of the earliest examples of soybean-cuisine development in America, and have the advantage of worldwide acceptance from consumers who appreciate traditional and nontraditional Asian cuisine and flavors.

Turtle Island Foods Inc., Hood River, OR, is a locally grown company that brought the traditional Asian soy food, tempeh, to the U.S. vegetarian market. A cultured cake of beans and/or grains, tempeh is made by cooking and dehulling the beans and grains, and culturing them with Rhizopus oligosporus. According to Turtle Island company literature, “The product is then incubated overnight at 88ºF,” until the mass is covered with “a thick, white mat of mycelia that binds the ingredients together into a solid cake.” The company combines soy with rice, millet, sunflower and sesame seeds to create five varieties of tempeh for retail distribution. Its product line now includes deli meats and veggie burgers from fermented soy bases. The deli slices are constructed from tofu, wheat protein, white beans and garbanzo beans; the firmness of tempeh cake provides an excellent base for veggie burgers.

In April of 2001, Vitasoy USA Inc., South San Francisco, CA, announced its solution to vegan convenience food with four flavors of baked tofu. The company expects to gain some market share with its nontraditional ethnic gourmet flavors, such as chile picante and mesquite. The company also is quick to point out that each serving has 53 mg of soy isoflavones and 19 grams of soy protein.

As a specialty business, tofu and tempeh are gaining a small, but devoted following. However, the most widely marketed veggie burgers and analogs usually are based on one or more combinations of processed soy proteins. Cheryl Borders, manager soy food applications, ADM, describes the overall challenges facing the product developer creating vegetarian analogs from soy proteins: “When developing a meat analog, the product developer must add the characteristic attributes inherently found in the meat counterpart. The meat product contains flavor, color, fat and texture — all qualities which the product developer must add to the vegetarian analog.”

Soy protein selections
The three most common forms of soy used (in order of their protein content) are derivatives from one of the three major groups: soy flours, soy protein concentrates and soy isolates. Functionality is an important aspect of vegetable-protein. Unlike meat proteins, the food technologist has many options for purchasing specific vegetable-protein functionalities within very large and diverse product lines.

Functionality depends largely on how the protein was processed and how it is combined with other ingredients. The most valued functional characteristics typically focus on water retention, emulsification (fat and water binding) and texture enhancement through gelation or other means. These attributes are critically important to the flavor and appearance of a meat analog, allowing it to achieve the mouthfeel and juiciness of a cooked meat product. Soy proteins generally bind 1 to 6 grams of water per gram of protein; therefore water is usually one of the first two most abundant ingredients in vegetable-protein products. The presence of both lipophyllic and hydrophyllic amino acids on the same polymer account for protein’s ability to act as a binder to water and fat. Soy proteins tend to be fairly insoluble, therefore they swell when hydrated and form a suspension rather than a true solution in water.

Soy flour is made by grinding soybean flakes, with or without their natural oil. Flours made from defatted soy flakes, a flake that has undergone an oil extraction process, contain about 50% protein, while the full-fat flours are closer to 40% protein. Defatted soy flour makes an excellent raw material for texturizing into granular products to simulate ground beef or sausage for burgers or pizza toppings. For example, Boca Foods Company, Madison, WI, uses organic texturized soy flour in its All American Classic Boca™ Burgers.

For some products, however, soy protein concentrate may be the chosen form. Soy concentrate, available in textured and powdered forms, is 70% protein and contains soy fiber, but lacks the carbohydrates that are associated with flatulence and other unpleasant aspects of bean digestion. Like high-protein soy flour, it’s made from defatted soy flakes. The concentrate generally has a cleaner flavor profile, with less “beany” and green notes, but also is higher in protein and more costly. This is the main ingredient in Boca’s Original Chik’N Nuggets™. The soy protein concentrate is combined with soy protein isolate and textured wheat gluten to achieve a chicken-like texture. Gardenburger, Portland, OR, built its Gardenburger Hamburger Classic™ on “hydrated soy protein concentrate,” a clever way of eliminating water from the ingredient list. Boca’s Vegan Original, with one of the shortest ingredient lists in the industry, builds its vegan entry from soy protein concentrate alone.

Soy protein concentrates are manufactured by two different methods: alcohol washing or aqueous acid leaching. The alcohol-washed concentrates are used frequently for making textured soy concentrate. After heating and homogenizing alcohol-process concentrates, they exhibit gel-forming characteristics and improved functionality. The aqueous acid-leaching process imparts water-binding and fat-emulsifying characteristics. Temperature and pH affect the emulsifying properties of the final products. Both types of protein concentrates can be spray-dried and dehydrated in the final application. The concentrates sometimes require more water for hydration than soy flours.

Soy protein isolate, at 90%, is closest to pure protein. It is considered to have more functionality than protein concentrates and can be texturized or spray-dried. Isolates have the lightest color and blandest flavor. They frequently appear in meat-analog products in combination with soy flour or protein concentrates for their ability to bind fat, act as adhesives, and impart gelling and viscosity characteristics.

Other alternatives
Soy and wheat aren’t the only sources of protein in meat analogs. Eggs, cheese and other dairy ingredients and a variety of grains have made their appearance in many formulas.

For some veggie burgers, eggs have partnered with soy protein as a binder, protein source and texturizer. A patent (Proctor & Cunningham 1985) demonstrated that eggs behave similarly to beef jerky in a formula of 35% to 65% whole eggs and 10% to 30% textured soy protein. Egg whites, composed primarily of protein and free of fat, are the ingredient of choice. They can help round out the amino-acid profile of non-soy-based products and also act as the “glue” in a grain and vegetable patty.

Cheese also is found on the ingredient list of many meat patties and analogs. The Gardenburger Original® features many dairy ingredients on the label: mozzarella cheese, cottage cheese curd, natural butter flavor, Cheddar cheese, several forms of whey, dried cream cheese and dried buttermilk. This burger is not soy-based; the structure is framed by a combination of mushrooms, rice, oats and bulgur wheat.

For today’s true veggie lovers who don’t require a traditional meat analog for acceptability, the Gardenburger Veggie Vegan™, at approximately 5% protein, is loaded with seven types of vegetables in addition to brown rice, rolled oats and bulgur wheat. With the addition of vegetable gum, sunflower oil and some wheat gluten, this burger may hold its own on a bun, but is not designed to deliver the savory hamburger flavor that the soy protein burgers can achieve. For that purpose, Gardenburger developed the Flame Grilled™, with 20% protein from soy and wheat, natural grilled flavor, caramel color, soy sauce, and other ingredients that create its dark, meaty appearance. It is the formula for the vegan burger that satisfies the carnivorous appetite.

The United Kingdom market is still the most diverse in the meat-analog sector in both frozen and chilled markets — it developed meat analogs from Fusarium, a fungal microorganism that the marketers prefer to call “mycoprotein” and liken to mushrooms for the benefit of consumers. A fermentation product, the fibrous protein has been marketed to the UK veggie-meat sector as Quorn™ since 1985 by Marlow Foods, now a subsidiary of AstraZeneca, Wilmington, DE. The U.S. product launch for Quorn was May 2001, at the Food Marketing Institute annual meeting, and regional rollouts will begin pending an expected approval of the protein source by the FDA this summer.

Flavors make the grade
Vegetable proteins with bland flavor profiles are more acceptable because they are easier to flavor. Kath Whittaker, managing director, Mastertaste, Bristol, UK, a division of Kerry Group, says, “Nearly all analog products tend to soak up flavor like a sponge, which results in high usage levels of flavors.”

According to Whittaker, the most important considerations in flavored meat analogs are the protein raw materials, the process and the end-product application — for example, whether the product will be eaten hot or cold. Some raw materials give the base undesirable flavors. When creating the desired end-product flavor, it is critical to mask these before building up the target flavor profile. Flavor houses have specific reaction systems and masking flavors to achieve this.

“Analysis of the ‘real’ meat product is used as a reference or bench mark when creating analog flavor systems, and by using a wide range of building blocks, experienced flavorists can build the target profile,” says Whittaker. “It is crucial to test the flavor with the correct base and processing method at each stage of development to ensure the correct flavor delivery after processing. Sensory evaluation using quantitative descriptive analysis (QDA) is a vital tool in this process.”

Soy protein binds volatile flavor components particularly well when it undergoes heat denaturation. Factors influencing protein binding to flavor volatiles are temperature, pH, concentration and the presence of water. Proteins may bind more or less of a flavor component, depending on length and extent of heat treatment. Binding due to hydrophobic interactions and hydrogen bonding between flavor and protein is reversible, unlike covalent binding, such as Schiff base formation (aldehydes and amino groups), which is irreversible. Irreversible protein-flavor binding can reduce the impact of desirable flavors and carry undesirable flavors to sensory receptors. Flavorists know that one of the most widely studied, documented protein-flavor interactions is the binding of off-flavors to soy proteins.

A wide variety of flavors have been introduced for vegetarian meat analogs. Numerous functional ingredients can be added to give specific properties to the flavor, many derived from yeast and some from soy flour itself. Soy flour, treated with enzymes and fermented, can be used as a flavor enhancer and imparts benefits similar to a yeast extract. This is labeled as “fermented soy flour.”

Yeast extracts owe their enhancement ability to naturally occurring 5'-nucleotides that potentiate and round out the flavor without contributing flavor. Yeast extracts also are known to mellow an acid bite, masking the apple-cider vinegar or citric acid that sometimes is added to vegan veggie burgers. Adding yeast not only boosts flavor, but also improves mouthfeel. Yeast extract or autolyzed yeast extract have found a place on many vegetarian labels, presumably due to the longstanding healthy reputation of brewers yeast and torula yeast.

Many vegetarian meat flavors can be derived from vegetable oils heated with amino acids and sugars to encourage Maillard reactions, the same type of reaction that takes place when meat is cooked. Certain flavors are specific to certain types of cooked meat and may be termed “roast chicken,” “grilled beef” or “bacon.” To add taste and mouthfeel, a fat flavor might be added to round out the flavor profile. Many manufacturers prefer products labeled as “natural flavor from vegetable sources.”

What about vegan seafood? Max Maxwell, business development manager, Kerry Ingredients, Beloit, WI, notes, “Very few vegan seafood flavors exist, as most seafood flavors are fish-based. One can use sea salts, ocean-plant-derived flavors and many of the flavors associated with various seafoods to meet these flavor profiles.” Matching the texture, appearance and other flavors characterizing a specific seafood application is the best way to meet the needs of most seafood replacers.

Veggie meats that have a slighter sweet flavor profile, such as ham or Canadian bacon analogs, can use evaporated cane juice (available as an organic ingredient) for sweetening. Other carbohydrates added to veggie meats are binding polymers, such as xanthan gum, carrageenan, hydrolyzed oat flour, cornstarch, rice starch, konjac flour, tapioca, gum arabic, locust bean gum, guar gum and wheat maltodextrin. Some of the ingredients, such as konjac, can foster the appearance of fat in the product by forming small white inclusions.

Labels and regulations
One difference between veggie meats and their meat-based counterparts is that many analog products rely more heavily on organic-ingredient sourcing for attracting consumer attention, and building and maintaining brand equity. The importance of organic certification in sourcing food ingredients for vegetarian analogs will continue under the new USDA ruling.

The Organic Foods Production Act of 1990 requires the USDA to develop national standards for organically produced products, and after 10 years of consensus building, the final rule was published in the Federal Register in December 2000 (www.ams.usda.gov/nop/). Full implementation is expected by mid-2002.

Section 205.605 refers to nonagricultural substances allowed as ingredients in or on processed products labeled as “organic” or “made with organic.” Some of the listed ingredients commonly found in veggie products include flavors, yeast, natural colors, alginates and xanthan gum. Allowable non-organically produced substances in organic foods are found under section 205.606 and include native cornstarch, bean gums, kelp, unbleached lecithin and pectin. Product developers should be aware of the organic status of their food ingredients under the new ruling, particularly for natural flavors, as they differ from other definitions of natural flavor.

While not all vegetable-protein products are 100% organic, most of them sport the label “made with organic soy.” According to the new FDA rule, this means no genetically modified foods. The Wall Street Journal decided to challenge GMO-free labeling by testing 20 products labeling that claim. One product tested showed 40% of the soybean DNA in a veggie bacon came from genetically modified plants. The reproducibility of testing methods is being questioned, and until standard test methods are adopted for the industry, companies that claim GMO-free may be setting themselves up as the next media target.

Sourcing ingredients to please the consumer has never been so exciting and so complicated. Alan Routh, chief executive, SunRich Inc., Hope, MN, which supplies non-GMO soy, was quoted in the Journal article, “I wouldn’t say GMO-free.”

Whether positioned for the natural foods market or just for general consumption, the FDA provides a regulation for labeling vegetable protein in vegetable-based meat, poultry, seafood, egg or cheese replacements. Protein sources of less than 65% protein are to be labeled with the source and term “flour.” If the protein content by weight is at least 65% and less than 90%, the term designated is “protein concentrate,” and if the protein content is 90% or greater, the label suggested is the source and the term “protein isolate or isolated ______ protein.” Terms such as “bits” or “granules” may be used to describe the physical form of the product.

Health news
In addition, those who formulate with soy protein might consider flagging the health benefits. For more than a year, the FDA has deemed the relationship between soy and cardiovascular health worthy. Products that contain at least 6.25 grams of soy protein per serving, and meet specifications for sodium and saturated fat, are approved for labeling health claims regarding soy protein’s contribution to reducing heart-disease risk.

Nutrition is the driving force for both vegetarians and “alternavores” who substitute soy proteins for animal products. Mark Messina, associate professor, Loma Linda University, Loma Linda, CA, and vegetarian nutritionist for ADM, explains that soy is becoming part of the American diet. “The National Soybean Board reported that 27% of consumers now eat a soy product once a week.”

Messina gives some of the credit for that to isoflavones, such as genistein and daidzein, the benefits of which can be realized with only one to two servings of soy products a day. “Studies such as the 1998 Jacobsen study of Seventh Day Adventists men have shown that two glasses of soy milk a day reduced the rate of prostate cancer by 70%, but do not appear to lower testosterone levels. An epidemiological study published in the Journal of National Cancer Institute (1998, 90, 21:1637-47) found that soy protein was protective against prostate cancer mortality in 42 countries. The phytoestrogenic (phyto refers to biologically active substances found in plants) effects of isoflavones have been documented in a number of studies in various soy-eating populations. They include a lower incidence of menopausal symptoms, reduced breast cancer and decreased risk of endometrial cancer.”

These health benefits, as well as improved technology that make eating meat analogs a pleasurable experience, should ensure continued consumer interest in “veggie meats.”

Suanne J. Klahorst, an omnivore, is associate director of the California Institute of Food and Agricultural Research (CIFAR) at the University of California, Davis. She often is observed free-ranging for veggie meats and tofu delicacies in the Sacramento and Davis Food Co-ops.

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