Plant-based proteins, especially as analogues for animal meat products, are entering consumer markets in unprecedented numbers. They promote healthier and ecologically sustainable alternatives to meat, dairy and other products. The marketing strategy is based on creating a modern food supply that benefits humans, animals and the environment alike.
However, with their rapid rise in popularity, concerns have arisen over the potential nutritional and safety hazards of shifting from an omnivorous diet to a plant-based one. An array of challenges has been identified, including the presence of harmful chemicals and microbial contaminants in the ingredients, concerns about food adulteration, excessive use of food additives, the use of genetically modified components, mislabeling, the introduction of new allergens and the possibility of vitamin/mineral deficiencies while altering the protein quality.
The incentives for plant-based proteins are enticing. The market for plant-based alternatives is expected to soar to $85 billion by 2030, a considerable jump from $4.6 billion in 2018, according to a UBS report “The Food Revolution.” Higher-income nations, which constitute only 17% of the global population, could help reduce greenhouse gases by 61% by adopting a more plant-based diet while also increasing carbon sequestration.
How they’re created
Proteins are obtained from plants such as soybeans, peas, corn and other crops. Turning them into meat analogues involves four major phases.
Initially, plant proteins are extracted and refined to form flours, concentrates or isolates. Following this, they’re blended with other ingredients, including carbohydrates, lipids, salts, flavors and colors, to achieve a meat-like texture, flavor and cooking quality. This mixture is then subject to various processing operations that encourage the development of meat-like structures and characteristics.
Various conventional methods use harsh chemicals like acids, bases and organic solvents to extract and purify proteins. Nowadays, green extraction methods that utilize single or mixed enzymes and advanced physical extraction methods like ultrasound, electric pulsed field, microwave and high-pressure-assisted extraction also can be employed.
It's worth noting that many of these protein extraction methods were not initially designed for plant proteins, and therefore do not optimize functionality. Instead, they were created to extract oil or starch from plant materials, which can sometimes compromise protein functionality due to denaturation or aggregation.
It’s this production phase of plant-based ingredients that poses the most concerns about food safety and nutritional quality.
To ensure the plant-based meat analogue is safe to consume and of high quality, the product, packaging materials and environmental conditions must be carefully designed and controlled during storage, transportation and distribution. This necessitates understanding the mechanisms of microbiological, chemical and physical deterioration.
Some plant proteins, including soy, wheat, pea and lupin proteins, are known allergens that may induce health problems for particular consumers. Additionally, some people are apprehensive about consuming plant proteins (particularly those derived from soy) that are obtained from genetically modified sources. Moreover, the use of organic solvents (such as hexane) during protein extraction can lead to environmental and health risks, especially if significant residual amounts remain in the final product.
Then, during the processing stage, plant proteins are combined with a range of functional elements to achieve the end product's desired flavor, texture and appearance. This entails using colorings, emulsifiers, gelling agents, binding agents and flavorings.
Some consumers worry about the high number of additives in certain plant-based meat substitutes, which they regard as ultra-processed foods. In addition, nutritional issues have been raised about some of the ingredients used in these heavily formulated food items, such as saturated fats, refined flours and salts.
Many toxins, few amino acids
When formulating plant-based foods, it's essential to be aware of the possibility of natural toxins. Plants produce metabolites to defend against bacteria, fungi, insects and predators. Some prime examples include lectins in kidney beans, cyanogenic glycosides in apricot seeds, cassava, flaxseeds, and glycoalkaloids in potatoes.
Wild mushrooms may contain muscarine, while fresh lily flowers contain colchicine. Ginkgo seeds contain 4'-methoxy pyridoxine. Therefore, it's crucial to carefully choose and process plant-based ingredients to avoid, remove or deactivate any potentially harmful toxins.
Plant proteins have an amino acid composition that differs from meat proteins. They are often deficient in one or more essential amino acids vital to human health, ones that cannot be internally produced -- including methionine, lysine and tryptophan. Creatine, taurine and anserine, also missing in plant-based meat alternatives, play a crucial role in brain and muscle function.
Consumption of soy, pea, wheat and other plant proteins could result in allergic reactions for some people. Pea and peanut proteins, for instance, possess comparable structures, thereby causing cross-reactions in people with peanut allergies. Wheat proteins are often used as binders in plant-based meat products. They are common allergens that can cause mild-to-severe symptoms, including life-threatening anaphylaxis reactions.
People with wheat allergies and celiac disease may also be allergic to gluten, found in grains such as wheat, barley and rye. Therefore, it's essential to choose low-allergenic proteins and carefully process and label plant-based foods to prevent these unwanted reactions.
The use of carrageenan, a seaweed-derived polysaccharide, as a food ingredient has been criticized by some researchers. While it has numerous applications as a stabilizing, gelling or thickening agent in meat substitutes, one study, from before 2008, linked carrageenan to gastrointestinal inflammation, bacterial imbalances, irritable bowel syndrome and colon cancer.
While that single study has been questioned, less defensible is that if carrageenan is extracted from contaminated seawater, it can accumulate dangerous levels of heavy metals, thereby posing a significant health threat.
Burgers that ‘bleed’ and ooze fat
Part of the early success of Impossible Foods’ Impossible Burger was its use of soy leghemoglobin to mimic the taste and texture of beef and pork, including a red hue that resembles meat juices.
While it can be obtained from soybean roots, the protein is typically produced using modified yeast. Either way, questions are raised about the use of genetic modification.
In addition, some studies suggest that increased heme iron intake is linked to higher body iron stores and a greater risk of type 2 diabetes. However, it’s worth noting that current scientific evidence indicates that the levels of leghemoglobin used in plant-based foods are not harmful.
Fats are sometimes added to further mimic the sensation of eating a real burger – a plus for sensory enjoyment but a minus for health.
There has been growing apprehension over a medley of additives such as flavorings, colorings, binding agents, preservatives and sweeteners. In addition, formulating meatless products with liquid smoke flavorings can pose a risk, as excessive consumption of these additives is known to be carcinogenic.
The high salt content in some plant-based meats is a cause for concern as it can lead to health issues like cardiovascular disease, high blood pressure, osteoporosis, kidney disease and stomach cancer.
Finally, there’s the cook step. Legumes, grains and vegetables may carry harmful bacteria. So just as with meat products, proper thermal processing is crucial to ensure that meat analogues are safe to consume. This can be done at the factory, restaurant or home.
As plateauing sales and the departures of big companies from this category indicate, plant-based meat analogues are not all the rage they were a few years ago. But they have made inroads that probably never will be given up, and the current generation of meat-replacers is far better than that first soy burger created by an ADM scientist back in 1991. Continuing development, with one eye on food safety, will only further enhance the category.
