Meat analogue

Hong Kong-style tofu from Buddhist cuisine is prepared as an alternative to meat

A meat analogue, also known as a meat alternative or substitute, or as mock, imitation, faux, fake, vegetarian, or vegan meat, approximates certain aesthetic qualities (such as texture, flavor, appearance) or chemical characteristics of specific types of meat. Generally, meat analogue means a food made from vegetarian ingredients, and sometimes without animal products such as dairy. Many analogues are soy-based (e.g. tofu, tempeh) or gluten-based, but now may also be made from pea protein.

The target market for meat analogues includes vegetarians, vegans, non-vegetarians seeking to reduce their meat consumption, and people following religious dietary laws in Hinduism, Judaism, Islam, and Buddhism. Increasingly the global demand for sustainable diets in response to the outsized role animal products play in global warming and other environmental impacts has seen an increase in industries focused on finding substitutes similar to meat.

Meat substitution has a long history. Tofu, a popular meat analogue made from soybeans, was known in China during the period of the Western Han dynasty (206 BCE – 9 CE).[1] A document written by Tao Gu (903–970) describes how tofu was called "small mutton" and valued as an imitation meat. Meat analogues such as tofu and wheat gluten are associated with Buddhist cuisine in China and other parts of East Asia.[2] In Medieval Europe, meat analogues were popular during the Christian observance of Lent, when the consumption of meat from warm-blooded animals is forbidden.[3]

Tofu, a popular meat analogue, was invented in China by the Han dynasty (206 BC–220 AD). Drawings of tofu production have been discovered in a Han dynasty tomb.[1][4] Its use as a meat analogue is recorded in a document written by Tao Gu (simplified Chinese: 陶谷; traditional Chinese: 陶穀; pinyin: Táo Gǔ, 903–970). Tao describes how tofu was popularly known as "small mutton" (Chinese: 小宰羊; pinyin: xiǎo zǎiyáng), which shows that the Chinese valued tofu as an imitation meat. Tofu was widely consumed during the Tang dynasty (618–907), and likely spread to Japan during the later Tang or early Song dynasty.[1]

Prior to the arrival of Buddhism, China was predominantly a meat consuming culture. The vegetarian dietary laws of Buddhism led to development of meat analogues as a replacement for the meat-based dishes that the Chinese were no longer able to consume as Buddhists. Meat analogues such as tofu and wheat gluten are still associated with Buddhist cuisine in China and other parts of East Asia.[2] Meat analogues were also popular in Medieval Europe during Lent, which prohibited the consumption of warm-blooded animals, eggs, and dairy products. Chopped almonds and grapes were used as a substitute for mincemeat. Diced bread was made into imitation cracklings and greaves.[3]

John Harvey Kellogg developed meat replacements variously from nuts, grains, and soy, starting around 1877, to feed patients in his vegetarian sanitarium.[5]

There was an increased interest in meat analogues during the late nineteenth century and first half of the twentieth century.[6] Prior to 1950, interest in meat analogues came from vegetarians searching for alternatives to meat protein for ethical reasons and regular meat-eaters who were confronted with food shortages during World War I and World War II.[6]

Dietitian Sarah Tyson Rorer authored the cookbook, Mrs. Rorer's Vegetable Cookery and Meat Substitutes in 1909.[7] The book includes a mock veal roast recipe made from lentils, breadcrumbs and peanuts.[7] In 1945, Mildred Lager commented that soybeans "are the best meat substitute from the vegetable kingdom, they will always be used to a great extent by the vegetarian in place of meat."[8]

Some vegetarian meat analogues are based on centuries-old recipes for seitan (wheat gluten), rice, mushrooms, legumes, tempeh, yam flour or pressed-tofu, with flavoring added to make the finished product taste like chicken, beef, lamb, ham, sausage, seafood, etc. Other alternatives use modified defatted peanut flour, yuba and textured vegetable protein (TVP); yuba and TVP are both soy-based meat analogues, the former made by layering the thin skin which forms on top of boiled soy milk,[9] and the latter being a dry bulk commodity derived from soy and soy protein concentrate. There is also algae powder (i.e made from such algae such as Chlorella, Spirulina, ...).[10] Some meat analogues include mycoprotein, such as Quorn which usually uses egg white as a binder. Another type of single cell protein-based meat analogue (which does not use fungi however but rather bacteria[11]) is Calysta.

Dairy analogues may be composed of processed rice, soy (tofu, soymilk, soy protein isolate), almond, cashew, gluten (such as with the first non-dairy creamers), nutritional yeast, or a combination of these, as well as flavoring to make it taste like milk, cheeses, yogurt, mayonnaise, ice cream, cream cheese, sour cream, whipped cream, buttermilk, rarebit or butter. Many dairy analogues contain casein, which is extracted dried milk proteins, making them unsuitable for vegans.

Egg substitutes include tofu, tapioca starch, ground flax seed, aquafaba, mashed bananas, applesauce and commercially prepared products that recreate the leavening, binding or textural effects of eggs in baked goods.

Soy protein isolates or soybean flour and gluten are usually used as foundation for most meat analogs that are available on the market. Soy protein isolate is a highly pure form of soy protein with a minimum protein content of 90%. The process of extracting the protein from the soybeans starts with the dehulling, or decortication, of the seeds. The seeds are then treated with solvents such as hexane in order extract the oil from them. The oil-free soybean meal is then suspended in water and treated with alkali to dissolve the protein while leaving behind the carbohydrates. The alkaline solution is then treated with acidic substances in order to precipitate the protein, before being washed and dried. The removal of fats and carbohydrates, results in a product that has a relatively neutral flavor.[12] Soy protein is also considered a “complete protein” as it contains all of the essential amino acids that are crucial for proper human growth and development.[13]

Lipids are added to the meat analog in the form of liquid or semi-liquid glyceride shortening from synthesis, or other sources such as plants or animals. The glycerides could potentially contain unsaturated or saturated long chain acyl radicals ranging from 12 to around 22 carbon atoms. Due to the target audience of meat analogs, plant based lipid sources such as soybean oil, olive oil, canola oil, and others alike are usually used.[14] While lipids do not contribute to the structure of the meat analog, it is crucial in increasing the palatability and broadening the appeal of the product across the consumer base.

Food additives include flavor compounds, coloring agents, leavening agents, and emulsifiers. Sodium bicarbonate is a commonly used leavening agent in a variety of baked products such as bread and pancakes. The carbon dioxide released by sodium bicarbonate aids in the expansion and the unilateral stretching of the protein network during production. A variety of emulsifiers can be used to stabilize the meat analog system. These could include, but are not limited to polyglycerol monoesters of fatty acids, monoacylglycerol esters of dicarboxylic acids, sucrose monoesters of fatty acids, and phospholipids. Polyglycerol monoesters consist on average of 2 to 10 glycerol units and an average of one acyl fatty acid group per glycerol component. The polymer is created from esterification reactions with fatty acids and contains 14 to 16 carbons per polyglycerol moiety. Sucrose monoesters are derived from the esterification of sucrose with a fatty acid ester or a fatty acid and it ideally should have a fatty acyl group ranging from 14 to 18 carbon atoms. Lastly, phospholipid such as lecithin, cephalin, and sphingomyelin can also be used as effective emulsifiers.[14] In addition, some of the emulsifier act as a lubricant during the extrusion process.

Overall the composition of dry protein mix can contain between 30% to 100% water-hydratable, heat-coagulable protein by weight. A dry mix that contains 100% protein content yields the most desirable fibrous texture, but from the palatability standpoint between 50% to 70% was determined to generate the most positive feedback.[14] Protein content of lower than 30% would inhibit the formation of meat-like fibers during processing. The optimal fat content for the desirable mouth feel was determined to be around 30% to 40% by weight.

Meat analog products are currently made by two basic processes, through either thermoplastic extrusion or fiber spinning. Thermoplastic extrusion involves the adaptation of production processes that are more commonly associated with the making of ready-to-eat cereal products. Extruders are considered to be a cost-effective method of accommodating large-scale productions, and for forming desirable fibers.[15] The wet mix is mixed in a heated vessel at a temperature lower than the coagulation temperature of the proteins. The elevated temperature assists in lowering the viscosity of the dough and allows for a more homogenized mixing process. Special caution must be taken as to not overmix the dough as it has been known to substantially decrease the amount of fibers formed.[13]

Extruders should be set to the temperature in which the protein used will start to coagulate for max efficiency. Gluten and soy proteins coagulate at 75 °C and 68 °C respectively. Due to the fact that the extruder also cooks the product, the temperature of the inner walls of extruder should be within the range of 77 °C to 149 °C. Turbulent conditions caused by aggressive mixing and agitation should be avoided during processing as it contributes to the undesirable formation of randomly oriented, non-meat like fibers. Unidirectional and parallel fibers can only be formed through extruding and stretching under none turbulent, or laminar, conditions. Laminar flow condition occurs under low velocities where the fluid in question flows smoothly with overlapping layers, and it is typically characterized by having a Reynolds number below 2000, though this depends on the system and can vary significantly in complex fluids. Stretching of the meat analog would take place simultaneously during the extrusion. Ideally, the amount of linear expansion of the protein dough should be around 50% in either direction.[13]

Fiber spinning method is not commonly used to produce meat analogs due to its complexity, and it also negates one of the key advantages of meat analogs. This method of production increases the cost of production, which eliminates the advantage of creating an inexpensive meat/protein substitute. The fiber spinning techniques were adopted from the spun fiber method used to create synthetic fibers in the textile industry. In general, fibers are made through creating filaments out of the protein used as the starting material. The process begins through the dispersion of proteins into a dispersing medium such as an alkaline aqueous solution. This dispersion is then fed through a spinneret, a device used to extrude a polymer solution to form fibers, and deposited into an acidic salt solution with a pH range of 5.6 to 6.4 for coagulation. The filaments after exiting the small die of the spinneret would have a diameter of around .003 inches. These filaments are then stretched and elongated until the average thickness is around 20 microns.[13]

Excess salt solution is then removed from the fibers through squeezing or centrifuging prior to further processing. After the drying process, edible binders such as proteins, starches, cereals, dextrins, carboxy methyl cellulose, or a combination of them, are added to keep the fibers physically tied together through functioning as an adhesive or serving as a matrix in which the fibers embed upon. The fibers are then passed through a bath of melted fat and proceed to be pressed together to form the final product. The meat analog is then cut into suitable length for either packaging and distribution or further processing.[13]

In April 2013, Beyond Meat began selling Beyond Chicken in Whole Foods Market stores in the US. A mixture of soy and pea proteins, fiber, and other ingredients, the well-received product was marketed as an alternative to chicken meat. The California-based company developed a number of other imitation meat products including three different products to mimic beef and one to mimic pork sausage.

In 2016, Impossible Foods introduced a beef substitute, which it claimed offered appearance, taste and cooking properties similar to meat.[16] In April 2019, Burger King introduced a new product, the Impossible Whopper which was released nationwide later that year,[17] becoming one of the most successful product launches in Burger King's history.[18] By October 2019, restaurants, such as Carl's Jr, Hardee's, A&W, Dunkin Donuts, and KFC were selling meat analogue products.[19] Nestlé entered the plant-based burger market in 2019 with the introduction of the "Awesome Burger".[20] Kellogg's Morningstar brand tested its new Incogmeato line of meatless meat-like products in early September 2019, with plans for a nationwide rollout in early 2020.[21]

These vegan meats are consumed in restaurants, grocery stores, bakeries, vegan school meals, and in homes. The sector for plant-based meats grew by 37% in North America over 2017–18.[22] In 2018–19, sales of plant-based meats in the United States were $895 million,[23] with the global market for meat analogues forecast to be $140 billion by 2029.[24] Seeking a healthy alternative to meat, curiosity, and trends toward veganism were drivers for the meat analogue market in 2019.[25] The changing importance of the meat analogues in the American diet was visible in the dramatic increase in purchases during the COVID-19 pandemic in the United States.[26] The book The End of Animal Farming by Jacy Reese Anthis argues that plant-based food and cultured meat will completely replace animal-based food by 2100.[27]