What is Protein?
Proteins are essential components of the human diet. They are found in skin, hair and muscle and all body tissues. A protein is made up of peptide building blocks with various combinations of 20 amino acids which determine proteins functionality and their nutritional value.1
Commercially, proteins are differentiated based on:
- Source: animal, insects, plants or microbes
- Protein content: concentrates (up to 80%) and isolates (higher than 90%).
Snacks and baked goods are ideal products for protein enrichment due to consumers’ need for foods that are highly nutritious, satiating and portable.
The word ‘protein’ may have its roots in the Greek word ‘proteios’ which means primary. Proteins, as biological molecules, were identified in the 18th century based on their tendency to coagulate. Their amino acid make up was identified in 1838 by two chemists Mulder and Berzelius.2
Adding proteins to foods and baked goods began with the recent low-carbohydrate trend. Today, proteins are considered one of the key nutritional ingredients in baked goods and snacks.
Commercial production of protein
Large scale production of proteins varies with the source and protein’s end use. Typically for plant proteins such as soy, isolation involves solubilization in water, precipitation and drying.
Membrane-based separation technologies are used in separating proteins from milk and other plant sources based on protein concentration (isolates/concentrates) or peptide size (hydrolyzates).
Proteins can boost humans nutritional well-being, stimulate muscle synthesis, satiety and help with weight loss as well as enhance athletic performance.
Animal-based proteins typically contain most essential amino acids in adequate amounts and are considered ‘complete proteins’. Plant-based proteins, however, are labeled ‘incomplete proteins” due to a lack of some essential amino acids.2
Consumption of proteins provides 4 cal/g protein.
Wheat and some grains contain proteins such as gluten which can trigger an autoimmune response in people with celiac disease.
Composition of commonly used food proteins in baking 1
- Grain proteins: gluten (gliadin, glutenin), albumin and globulin.
- Milk proteins: caseins (alpha-S1, alpha-S2, beta-casein, kappa-casein, glycomacropeptide) and whey proteins (beta-lactoglobulin, alpha lactalbumin, immunoglobulins, lactoferrin, lactoperoxidase).
- Oilseed proteins such as soy: glycinin, conglycinin and globulin.
In baking, proteins perform as dough conditioners, structuring agents and moisture controllers. Bread wheat flours contain higher levels of gluten resulting in a tough and chewy bite while cakes have a light and airy texture due to lower amounts of gluten in the flour.
Proteins serve several functions in foods and bakery systems such as foaming, emulsifying, viscosity building, gelling and water-binding, flavor and color development through Maillard reaction and much more.
Incorporating proteins into a wheat-based baking formula should first and foremost take into consideration the potential effect on gluten development and on the final product volume and texture.
Typical proteins used in baked goods include:
- Milk proteins improve the nutritional value of baked goods and can impart desirable flavor and color, a result of undergoing Maillard reactions. Their versatility makes them excellent candidates for egg replacement. Sodium caseinates addition to bread provides similar functionality to that performed by ascorbic acid or DATEM. Whey protein concentrates, on the other hand, can depress bread volume and affect texture negatively.
- Grain proteins such as wheat gluten are responsible for baked goods’ unique texture. The gliadin fraction helps with dough extensibility and viscosity while gluten provides strength and elasticity. Addition of vital wheat gluten to baking systems allows the development of high-fiber foods with desirable texture and other sensory attributes.
- Oilseed proteins such as soybeans provide baked goods with excellent water binding, gelling, consistency and other desirable textural attributes. Drawbacks of using soy proteins include their potential allergenicity and beany flavor.
Considerations when fortifying baking systems with proteins:
- Some proteins attract a lot of water and can lead to a very stiff dough. Others will not attract water and make the dough very soft, which makes it hard to develop the gluten.
- The ability of vital wheat gluten to sequester water can help with reducing moisture migration in frozen baked foods and doughs.
- Lower-viscosity proteins will have less effect on volume loss than higher-viscosity proteins.
- Non-wheat protein sources can provide a wide variety of textures from crunchy to crispy.
The FDA considers food proteins as GRAS (21CFR101.54). 4
- Fenema, O.R., Srinivasan, D. and Parkin, K.L. (Editors). Introduction to Food Chemistry. 5th edition, 2017, CRC Press, 1123 pp.
- Mulder, G.J. 1938. Sur la composition de quelques substances animals. Bulletin des Sciences Physiques et Naturelles en Neerlande, p. 104.
- Hoseney, R. C. Principles of Cereal Science and Technology, St. Paul, MN, USA. Am. Assoc. Cereal Chem. 1986, 68.
- CFR – Code of Federal Regulations 21CFR101.54” Accessdate.fda.gov. 01 Apr. 2019. https://www.accessdata.fda.gov/scrIpts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.54. Accessed 12 Nov. 2019.
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