The Ties That Bind: An Overview of Food Binders
“Food is the ingredient that binds us together.”
– Gary Mehigan
Food is a sensorial experience – the eyes initiate the appetite, the nose detects fragrances, and the bite reveals taste and texture. Cooking enhances the experience with the sights and sounds of grilling, frying, or sizzling, coupled with the gratification of creating a dish. Because food engages every one of our senses, we have become accustomed to demanding excellence in every facet of its preparation and consumption. To meet this standard, products utilize a panoply of ingredients to enhance the nutrition, taste, texture, or appearance. A binder or binding agent is a key ingredient that glues structural elements to form a cohesive matrix. In providing the glue, binders create magic by uniting the various components that make up the foods we have come to love. This is precisely why the food industry needs binders. The alternative protein sector is no different.
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The Alchemy of Binders
A ‘binder’ in food is an umbrella term used to refer to any substance that holds various components (proteins, fat particles, oil droplets, seasonings) of solid food together. Interactions at a molecular level between binders and these components lead to a structured product. The result is the creation of a food material matrix leading to structural cohesiveness, the defining trait of binders1. Beyond structural stability, binders can help in moisture retention, gelation, emulsification, and flavor encapsulation, as well as other benefits. These varying attributes both enhance the texture and mouthfeel of the product and impact nutrient digestibility and bioavailability. In essence, binders ensure that a burger patty remains cohesive through the cooking process, yet morphs from a soft, raw substance to a fibrous, chewier form, that oozes flavor with each bite. Most meat and alternative meat products simply wouldn’t come together (literally) without binders.
Today, we see binders utilized in the fanciest gastronomic creations, but they had extremely humble beginnings going back centuries. The first recorded use of binders, intentional or inadvertent, dates back to the creation of bread. Upon settling down in agrarian societies, humans started crushing grains and mixing them with water before cooking. Kneading the mixture created interesting texture profiles, which resulted from the binding properties of grains such as wheat gluten, the protein present in wheat. Today, eggs are the most popular natural binding agent, followed by flour. With the advent of modern technology, synthetic binders are now widely employed in the food industry, particularly in baked goods and meat products. 84 different binders of plant and animal origin have been classified Generally Recognized As Safe (GRAS) by the USDA.
The Taxonomy of Binders
Binders commonly included in alternative meats are highly varied. They may be protein-based, fiber-based, carbohydrate-based, starch-based, or fat-based.
Protein-based binders (e.g. soy protein, pea protein, algal protein) are highly functional due to their exceptional emulsification capabilities. These binders have high viscosity, which reduces leakage while cooking. In addition, these binders serve as a source of protein in meat analogues.
Fiber-based binders (e.g. methylcellulose, psyllium) result in improved textural properties due to excellent moisture retention capabilities. However, it is essential to utilize them in limited quantities to avoid impacting texture negatively.
Carbohydrate-based binders (e.g. xanthan gum, guar gum, carrageenan gum) are usually gums that can form a stable gel without a distinct color, taste, and odor. They also serve as fat substitutes and enhance shelf-stability of products. However, due to their sticky, viscous texture, their utilization must be closely monitored.2
Starch-based binders (e.g. potato starch, tapioca starch) tend to be cost-friendly due to ubiquitous raw sources, making them an easily available binding option. However, comparably larger quantities are required to attain similar outcomes to other binders.
Fat-based binders (e.g. vegetable oils) can provide binding at increased concentrations. Oil interacts with proteins and promotes hydrophobic exchanges and aggregation, resulting in a uniform gel network.3
Other binders (e.g. esterified alkoxylated polyol) explored for meat analogues include fat mimetics, which provide enhanced binding structure while lowering fat content.4
The Allure of Binders
Binders are indispensable in delivering the desired texture of the final product. Beyond structural stability, they can provide a cornucopia of additional functionality due to their chemical interactions with other ingredients. The benefits of binders span three key categories – taste, texture, and functionality.
The Magic (and Mayhem) of Methylcellulose
With a wide range of natural and synthetic binders available, one stands out above the rest – methylcellulose. Commonly found in alternative meat products, methylcellulose is a synthetic, modified form of cellulose, a compound found in abundance in plant cell walls and considered to be the building block of all plant life. It is produced by heating cellulose with a caustic solution, followed by treatment with methyl chloride, a colorless and odorless compound. Methylcellulose is a hydrocolloid known for its unique gelling, thickening, and binding properties. Its unparalleled thermally reversible gelling properties mean that it sets when heated to 65°C (~150°F) and melts upon cooling to 35°C (~95°F)5. No other binder (except for gellan gum to a limited extent) can mimic this behavior, adding to the uniqueness of methylcellulose. It is also extremely versatile in its applications with above average water-holding properties (it can absorb 50-100 times its weight in water), thus contributing to improved moisture retention in the final product6. Further, methylcellulose is an affordable binding agent that is readily available, making it the binder of choice for conventional and alternative meat products.
The use of methylcellulose is hampered due to consumer perception that it is a ‘processed’ ingredient given its chemical origins. With the growing popularity of ‘clean-label’ foods, consumers are becoming increasingly wary of ‘hyper-processed’ products. Methylcellulose is also the main ingredient in many laxatives, leading to concerns around its usage in food. The conventional meat industry has leveraged this opportunity to paint methylcellulose (and other synthetic additives) as dangerous, leading to negative associations with products that include them. None of this refutes that food safety organizations including the FDA in the U.S., EFSA in the EU, FSANZ in Australia and New Zealand, and even the Joint FAO/WHO Committee on Food Additives (JECFA) have approved the use of methylcellulose as an additive7. Ironically, it has been used in the conventional meat industry since the 1950s. Organizations often cap the use of methylcellulose at 2% of product weight. Both Impossible Foods and Beyond Meat have gone on the record to confirm that they adhere to this limit, as indicated on their product packaging. Methylcellulose has precedence, approval, and adherence in its use. Why, then, does its utilization in alternative meats cause such controversy? The gap between perception and reality is bridged by facts. When it comes to methylcellulose, the facts deserve greater attention and scrutiny.
In part due to these issues, numerous companies are working on alternatives to methylcellulose:
ICL Food Specialties and Plantible Foods have introduced ROVARTIS, a product created using duckweed RuBisCo protein to replace eggs and methylcellulose.
Meala FoodTech’s platform transforms plant-based proteins into functional ingredients, a direct methylcellulose replacement.
Oceanium produces a seaweed-based ingredient called Ocean Health Fiber as a replacement.
Fiberstar combines citrus fiber, agar, starch, and psyllium to create its substitute.
Shiru, a protein discovery and ingredient creation company, has teamed up with CP Kelco and Puratos to create alternatives.
Eggmented Reality uses bioinformatics to identify proteins with specific binding functionalities.
Peaazz Pea Protein, a product from Merit Functional Foods, is a soluble and neutral-tasting pea protein that can serve as a replacement for methylcellulose.
Alver’s Chlorella product is also a suitable replacement.
ReBind Food produces multifunctional, plant-based binders that can replace eggs and sugar.
Given the abundance of innovation, the next generation of products is likely to employ a range of methylcellulose alternatives.
We’re in a Bind
While binding agents currently utilized in alternative meat products were not always designed with this purpose in mind, their versatile functional properties have led to their repurposing in the industry. Today, we see companies mix and match binders to achieve desired binding effects. As the meat analogue market continues to grow, we can expect companies to focus on refining existing ingredients and discovering novel binding agents alongside them. With time, the industry will likely boast a greater spectrum of binding agents tailored to meet its evolving needs. Perhaps we won’t get past the long names, but the basic compound that is simply trying to hold everything together is bound to bind better.
Herz, Moll, Schmitt & Weiss (2023), Binders in foods: Definition, functionality, and characterization
Han et. al. (2023), Comparative Evaluation of Polysaccharide Binders on the Quality Characteristics of Plant-Based Patties
Kyriakopoulou, Keppler & Goot (2021), Functionality of Ingredients and Additives in Plant-Based Meat Analogues
Milhouse & Rowe (2022), Plant-based meat replicas with binders for plant-based food products, Patent Application No.: US 2022/014295
ChefSteps, Methylcellulose F50
Blaesi, Kummerlen, Richter & Saka (2022), Mechanical strength and gastric residence time of expandable fibrous dosage forms
Food Additives - What is Methylcellulose (E461) in Food: Uses, Safety, Side effects