WHAT is protein, what is complete protein + 15 COMPLETE Proteins vegetarians and vegans need to know

29 Mar, 2019 by Helena-Reet Ennet

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NordenBladet – “Complete protein” is a term referring to the building blocks of protein- amino acids. There are twenty different amino acids which form a protein. And, there are nine amino acids which the body cannot produce, known as essential amino acids. As the body is not able to produce them on its own, we need to eat them. For a protein to be considered complete, it must contain all nine essential amino acids.

What is protein?
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific three-dimensional structure that determines its activity.

A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteine and—in certain archaea—pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modified by post-translational modification, which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors. Proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes.

Once formed, proteins only exist for a certain period and are then degraded and recycled by the cell’s machinery through the process of protein turnover. A protein’s lifespan is measured in terms of its half-life and covers a wide range. They can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal or misfolded proteins are degraded more rapidly either due to being targeted for destruction or due to being unstable.

Like other biological macro molecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms and participate in virtually every process within cells. Many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized. Digestion breaks the proteins down for use in the metabolism.

Proteins may be purified from other cellular components using a variety of techniques such as ultra centrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic engineering has made possible a number of methods to facilitate purification. Methods commonly used to study protein structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance and mass spectrometry.

What is complete protein?
A complete protein or whole protein is a food source of protein that contains an adequate proportion of each of the nine essential amino acids necessary in the human diet. Examples of single-source complete proteins are red meat, poultry, fish, eggs, milk, cheese, yogurt, soybeans and quinoa. The concept does not include whether or not the food source is high in total protein, or any other information about that food’s nutritious value.

It was once thought that plant sources of protein are deficient in one or more amino acids, and so vegetarian diets had to specifically combine foods during meals, which would create a complete protein. However, the most recent position of the Academy of Nutrition and Dietetics is that protein from a variety of plant foods eaten during the course of a day typically supplies enough essential amino acids when caloric requirements are met.  Normal physiological functioning of the body is possible if one obtains enough protein and sufficient amounts of each amino acid from a plant-based diet. In fact, the highest PDCAAS scores are not given to commonly eaten meat products, but rather to animal-derived vegetarian foods like milk and eggs and the vegan food soy protein isolate.

Total adult daily intake
The second column in the following table shows the amino acid requirements of adults as recommended by the World Health Organization calculated for a 62 kg (137 lb) adult. Recommended Daily Intake is based on 2,000 kilocalories (8,400 kJ) per day, which could be appropriate for a 70 kg (150 lb) adult.

Protein can be found in many different sources, including vegan complete protein sources:

• Beans and peas
• Soy Grains and vegetables
• Nuts and seeds
• Dairy products
• Eggs
• Meats and poultry
• Seafood (fish and shellfish)
  Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs. Pictures: 8x Pexels

15 Complete Proteins Vegetarians and Vegans Need to Know:

Buckwheat

• Protein content: 6 grams per 1 cup, cooked.
• It comes from the rhubarb family and it isn’t a type of wheat
• Capable of improving circulation and lowering cholesterol levels
• Must try ideas: use buckwheat as a protein in chili recipes

Spirulina

• Protein content: 4 grams per 1 tablespoon
• Part of the algae family and technically not a complete protein because it doesn’t contain methionine and cysteine)
• You can turn it into a complete protein by adding seeds, nuts, oats, and grains
• Must try ideas: add a spoonful to your favorite smoothie

Chickpeas

• Protein content: 7.25 g per ½ cup.
• Tasty and quite versatile vegan protein source. Use them like you would beans
• Must try ideas: add them to stews and curries, roast them in the oven, add them to soups, or make hummus

Mycoprotein

• Protein content: 13 g of protein per ½ cup serving
• A fungus-based protein used as meat replacement
• Must try ideas: use it like you would with meat

Hemp Seeds

• Protein content: 5 g of protein per tablespoon
• They add a sweet and nutty taste to smoothies, salads, and meals.
• Must try ideas: Add it to smoothies, salads, fruits salads, and granola.

Almonds

• Protein content:  16.5 g of protein per ½ cup.
• A great snack.
• Beneficial for eye and skin health
• Help you meet your protein needs in a vegan way
• Must try ideas: make almond butter or add them to green salads, vegetable dishes, granola, cereal, or fruit salads

Quinoa

• Protein content: 8 grams per 1 cup, cooked.
• Packed with fiber, manganese, magnesium, and iron
• A great substitute for rice
• Must try ideas: use it as a filling for a breakfast burrito

Rice and Beans

• Protein content: 7 grams per 1 cup
• When used together, they have a protein content like meat
• A fantastic way to fill up after a workout
• Must try ideas: use them as a filling during taco night

Lentils

• Protein content: 8.84 g of protein per ½ cup
• Quite versatile vegan protein sources
• Must try ideas: try lentil soup or add it to rice, stews, curries, or salads

Potatoes

• Protein content: 8 g of protein per serving.
• Surprisingly, potatoes a great vegan protein source
• Must try ideas: add them to soups and casseroles or enjoy them steamed, boiled, baked, or mashed

Broccoli

• Protein content: 4 g of protein
• Adding broccoli to your life can significantly increase your vegan protein for the day
• Must try ideas: it is tasty in salads and stir-fries

Ezekial Bread

• Protein content: 8 grams per 2 slices
• Made from sprouted grains: spelt, lentils, wheat, barley, beans, and millet
• Packed with fiber and vitamins
• Must try ideas: use it as a base for a mini pizza

Seitan

• Protein content: 21 grams per 1/3 cup
• It has been used by Buddhist monks as a vegan protein source
• Cook it in a soy sauce- broth in order to add gluten’s missing lysine for a chewy, meat-like food
• Must try ideas: try seitan fajitas and stir-fry.

Pita and Hummus

• Protein content: 7 grams in one pita and 2 tbsp of hummus
• An easy lunch, but also works as a breakfast, snack, or dinner as well as a vegan protein-filled meal
• Must try ideas: add your favorite veggies to the pita. Add some seitan, beans, or other vegan protein sources

Tofu

• Protein content: 10 g of protein per ½ cup
• A great and quite versatile vegan protein source. It can be used as a meat substitute and it ss great for baking
• Must try ideas: try tofu scrambles for breakfast and baked tofu with your favorite side for lunch

Peanut Butter Sandwich

• Protein content: 15 grams in one sandwich
• Great for children who will not even notice that they are meeting their protein through a vegan protein source
• Always use natural and organic peanut butter
• Must try ideas: make peanut butter and jelly or peanut butter and honey sandwiches. You can also add peanut butter and nut butter to lettuce wraps and tortillas

Featured image: Pexels/Ella Olsson