In the past 10 years, there has been a lot of research into the quality of protein. As consumers become more interested in health and proactive nutrition, proteins are being used more often in general wellness, rather than just specialized nutrition.
In the past five years, there has been a 9% global increase in the number of food and beverage products that claim to be high in protein or a source of protein, according to Innova Market Insights.
With a focus on health and wellness, consumers are turning to plant-based protein options that are seen as being more sustainable. In the past five years, the number of food and beverage products containing plant protein has increased by 17%.
As the number of protein sources increases, people are becoming more concerned about factors such as the type of protein and its quality when making decisions about what products to buy. Manufacturers can improve sales by improving the quality of their protein-based products.
Protein Quality Differs Depending on Food Source
As protein becomes a bigger factor in consumers’ diets, they are increasingly concerned with the quality of the protein they’re eating. As plant-based food alternatives become more popular, it’s important to remember that not all proteins are the same.
Some protein sources are better than others at providing the nutrition and physiological benefits we need. There are a few ways to measure the nutritional quality of different protein sources, and people are becoming more aware of them.
Protein Amino Acid Composition
Amino acids (AAs) are the building blocks of proteins. Proteins are made of 20 common amino acids, 9 of which are considered essential amino acids.
Arginine and Histidine amino acids are classified as conditionally essential because they are only required in populations with specific physiological needs.
Without adequate amounts of EAAs (essential amino acids) in the diet, deficiencies can develop because the body cannot produce them.
Proteins that naturally contain adequate levels of essential amino acids (EAA) are often found in animal-derived sources, such as egg or milk. Plant proteins lack some of the essential amino acids that are necessary for human health. Rice does not contain enough Lysine, and peas do not contain enough Tryptophan.
Different crops, seasons, and protein extraction methods will result in different AA profiles for a protein source. Further processing, such as protein hydrolysis or heat treatment, can also affect the AA profile. The composition of EAA can vary depending on the main ingredient, such as a bean or grain, flour, protein concentrate, or protein isolate.
Another factor that affects protein quality is digestibility. During digestion, the gastrointestinal enzymes break down protein into peptides and amino acids.
The functions of amino acids are very important for things like hormone and neurotransmitter production, as well as muscle protein synthesis and various cellular processes. Proteins must be broken down into smaller pieces before the body can absorb them. Protein digestibility is an important factor to consider because it can affect the nutritional value of proteins.
Animal proteins are typically easier for the body to digest than plant proteins. The presence of anti-nutritional factors in plants is the reason for lower digestibility of plant proteins. These anti-nutritional factors can make it harder for the body to digest protein and reduce how much of the protein the body can use. The levels of antinutritional factors in plants may be reduced during protein extraction when the fractionation and heat inactivation process is followed.
Plant protein isolates have a high protein purity and low levels of antinutritional factors, making them a good choice for people looking to add protein to their diet. A method for improving protein digestibility is to isolated the protein from plants. Other methods that can be used to improve plant protein digestibility are soaking, boiling, microwaving, fermentation, or hydrolysis.
Texture and mouthfeel are important characteristics that affect a person’s experience of eating a food product. Soy proteins, soy protein concentrate, and soy flours can help improve the texture of food while also increasing the protein content.
Soy protein concentrates can be used to create products that have a similar texture and appearance to meat, without using actual meat. This can be beneficial for companies that want to create vegetarian or vegan products that still have the appearance and taste of meat products.
Textured soy flours do the same. If the right kind of soy protein is chosen, it can improve the texture of vegetarian hot dogs, yogurt, and other similar products.
The three types of textured or structured soy proteins are made from soy flour, soy protein concentrate or isolated soy protein. To create textured vegetable protein, soy flour is pushed through a machine that shapes it using heat and pressure.
There are many types of soy sausages, which come in different sizes, shapes, colors and flavors. Some sausages are even bacon-colored and bacon-flavored.
Combinations of soy protein or other powdered protein ingredients (i.e., wheat gluten) with various carbohydrate sources can produce unique textured protein products.
Formulators use products that contain wheat gluten more widely in vegetarian applications to simulate ground meats or meat chunks and strips. This is because wheat gluten provides a chewy, meaty texture that is similar to that of actual meat.
The products that are manufactured using thermoplastic extrusion technology are available in both dry and wet forms. The products can be hydrated with water or flavored solutions before being used in processed meat or vegetarian products.
Gelation is a process where protein molecules unfold and then come back together to form a gel.
This process is responsible for creating products that require a “thermal setting” like cake batters, custards, and puddings. When heated, egg white forms a gel coagulum that cannot be reversed, resulting in the desired textures. Different textures are created when a protein is able to change the viscosity of a product.
When whey proteins are heated under the right conditions, they form an irreversible gel by organizing themselves into a three-dimensional network. Water is held within the gel matrix, providing extra water holding capacity. Traditionally, foods containing whey protein ingredients would have to be heated above 65°C before the proteins would form gels or thicken solutions, which limits their use in many types of food products.
Water binding is especially important in food products that are viscous, such as beverages, soups, sausages and custards. A gel network helps hold water and prevent moisture loss.
The current focus of research is on creating cold-set gels: whey protein ingredients that can thicken solutions or create gels at ambient—and even refrigerated—temperatures.
The development of viscosity is closely related to the gelation properties and interactions between proteins. Soy proteins can enhance viscosity. Isolated soy proteins and soy protein concentrates are normally the proteins used for viscosity modification. Soy proteins can provide a wide range of viscosity profiles when they are isolated. The modification of soy proteins can result in products with very low to very high viscosity.
The functional properties of isolated soy proteins can vary dramatically. How well a soy protein works is largely based on the way it is processed. Three factors that have a significant impact on the functional qualities of finished isolated soy proteins are heat, homogenization, and pH.
Viscosity is an important element to consider when manufacturing beverages. Enzyme modification creates isolated soy proteins that produce very low viscosity for production of high protein beverages and infant formula.
How viscous and how well it gels are critical properties in the manufacture of soy yogurt. In cream soups and high fat sauces, it is important for the finished products to be stable and have the right texture. This is achieved through emulsification and viscosity. Applications that use processed meat require soy proteins that can emulsify and gel well.
Emulsions are stabilized by proteins at oil/water interfaces. Whole eggs and yolks contain both protein and lipids, which give them their emulsifying properties. Without eggs, baked goods would be less rich and moist, and would have a more crumbly texture.
Controlled denaturation of the protein can enhance emulsification properties. This means that they help to mix oil and water, which would otherwise not mix together.
Beverage manufacturers can modify whey protein isolate to fit their personal specifications by using a simple processing step, as stated by Dairy Management Inc. from Rosemont, Illinois.
Some possible uses for this product are baby formula, soda, fruit-based juice, and sports or health-related drinks.
Enzymatic bio-processing can tailor whey protein functions to specific needs such as gel strength, emulsion stability, and solubility. Researchers are hoping to find ways to improve edible films, nutritional drinks, and low fat meat products.
Foaming is the process of creating and stabilizing gas bubbles in a liquid. A protein’s ability to form foams is dependent on its diffusion to the air-water interface to lower surface tension, as well as its partial unfolding. Protein molecules are encapsulated by air bubbles and then adhere to each other, forming a film that is somewhat elastic. Foaming of protein solutions can have benefits in some cases, like when making aerated frozen desserts or meringues.
Egg white is an excellent food foaming agent. This is because the different proteins in egg white interact with each other to create a foamy texture.
In addition, products made from egg white foams that have undergone thermal coagulation have stable textures. Whipping agent-enhanced egg products that improve foam formation are also available.
Proteins can be made more functional through high pressure treatment and enzyme modification. Proteins can be denatured, aggregated, or gelated by high pressure. New protein ingredients with interesting textures and tastes could be created through high-pressure treatment of proteins. This would have a minimal effect on flavor and color.
Some potential uses for high-pressure processed egg whites are gelation while preserving natural flavor and nutritional value.
Process parameters such as pressure, time, temperature, protein concentration, pH and presence of salts can all influence the effects.
More research is needed to understand how high pressure affects proteins in food.
The hydrolysis of proteins affects the gelation properties in various ways. If you use enzymes to break some of the bonds in the gel, you can change how strong it is and how well it holds together.
The article by Dinakar Panyam and Arun Kilara at Pennsylvania State University described the tryptic hydrolysis of whey proteins. Tryptic hydrolysis at a degree of hydrolysis between 2.3% and 6.7% prevents gelation at pH 3.0 and pH 7.0, whereas hydrolysis to 2.3% DH with a Bacillus subtilis protease dramatically increases whey protein’s gelling ability and gel strength at neutral pH.
This suggests that it is possible to use tryptic digests at a high concentration in acidic beverages without the beverages resulting in gelation. The protease digests from B. subtilis may also be used in neutral pH foods, such as surimi.
Pepsin digests protein at a lower pH, so using it at pH 4.0 improved the characteristics of egg albumin gels. The ability to deliberately make weaker gels may be advantageous for some desserts.
Soy protein that has undergone partial hydrolysis is more soluble than soy protein that has not undergone hydrolysis. Panyam and Kilara found that soy protein that was hydrolyzed with ‘Alcalase’ (a bacterial protease from Bacillus licheniformis) resulted in a product that was highly soluble over a wide pH range.
Whey proteins tend to be more soluble at a higher pH, but denaturation causes them to be less soluble at a lower pH, because it creates larger clumps. Hydrolysis of heat-denatured whey protein isolate, especially by trypsin, partially restored the loss of solubility. PF
Plant Protein Combination
One common way to optimize the essential amino acid profile in protein formulations is to combine different plant protein sources in a complimentary fashion. The composition of the plant protein blend is based on the limiting essential amino acid in each protein source.
The most common essential amino acids lacking in dietary proteins, based on early studies, are Methionine, Lysine, Tryptophan, and Threonine.
Most plant proteins are not able to provide all essential amino acids. There are a few exceptions to the rule that plants don’t contain all essential amino acids, such as soy, potato and canola.
It is common practice to combine complementary plant proteins to improve the essential amino acid (EAA) profile and increase the dietary protein quality. An enhanced DIAAS/PDCAAS value can be achieved by combining a food that is limited in sulfur-containing amino acids (Methionine/Cysteine) or Tryptophan with a food that is limited in Lysine.
Food Formulation with Hybrid Proteins
Some products that contain a mix of different proteins have been available for a few years. However, the main objective of combining protein sources was not to create hybrid products, but rather to achieve a cost saving. The products, which include mostly protein bars and nutritional beverages, are fortified with a blend of dairy and plant protein. Food companies have an opportunity to more effectively communicate the hybrid positioning of their products, as well as the benefits of hybrid formulations.
Flexitarianism is on the rise, and as a result, so are vegan food products.
Since these consumers are eating animal-derived products, formulations that include both plant and animal proteins would still be consistent with the dietary choices of flexitarians. The goal of hybrid foods is to let people eat more plant proteins and fewer animal proteins.
One way to improve the nutritional quality of a protein product is to include both animal and plant protein. Animal protein is often complete and delivers all essential amino acids (EAAs). So far, there have not been many new food products that are a mix of two different types of food.
Many new products have been created recently, mostly in the dairy alternative area. Companies such as Premier Nutrition, Live Real Farms, Bel, and Triballat have all come out with new products that combine dairy with other things such as oats, almonds, and pulses.
As more consumers include plant-based protein in their diets, the quality of that protein is becoming an important consideration. In the future, it may become a key factor in differentiating products in a crowded market.
However, more education is required regarding the different parameters linked to protein quality such as the essential amino acid profile, the protein digestibility-corrected amino acid score, and the digestible indispensable amino acid score.
This gives protein food and beverage manufacturers a chance to make formulas that are better for you nutritionally and that your body can digest more easily. They can also teach you about protein quality and how it influences your overall health and nutrition.
There are several ways to improve protein quality, and as more new protein sources become available, protein quality will become an important factor for consumers when choosing between different options.
Consumer education on protein quality will help them choose foods with good nutritional value.