What Is Yeast Extract, What Is It Used For, And Is It Safe?

Yeast extract is a popular food ingredient. You may find it being used in different kinds of sauces, soups, snacks, and ready-made meals. To produce the extract, manufacturers use the same kind of yeast used for making wine, beer, and bread. With its unique savory flavor, the yeast extract adds to the overall taste of the food item, just as spices do. This is why many often call yeast extract the "hidden flavor enhancer" of foods.

Yeasts are single-celled organisms belonging to the kingdom Fungi.

Yeast extract is a natural food ingredient made from bakers' or brewers' yeast (Saccharomyces cerevisiae). This is the same fresh yeast used for centuries for fermenting beer, bread, and wine.

On an industrial level, yeast extract is usually made by this three-step process:

1. Manufacturers grow yeast in large containers called "fermentors," using sugar to nourish the yeast. They maintain a rich oxygen supply and a temperature of 30 degrees Celsius in the fermentor. These are similar to the conditions maintained while baking at home.
2. Manufacturers increase the temperature to 45 to 55 degrees Celsius so the yeast stops growing. Then they either use the enzymes already present in the yeast (autolysis) or add new enzymes (hydrolysis) into the fermentor. These enzymes break down the yeast proteins and the other macromolecules into smaller components and dissolve the cell walls to release the contents from the yeast cell.
3. Manufacturers mix the inner yeast cell content — the yeast extract — with the contents of the fermentor. After proper mixing, they separate the cell walls from the mixture and dry the filtered yeast extract.

Depending upon which process is followed in step 2, you either get autolyzed or hydrolyzed yeast extract. 

Some small-scale manufacturers make baker's yeast extract by grinding the dry yeast using a mortar and mixing it with water overnight. This is followed by centrifugation, filtration, dialysis, and freeze-drying steps. These processes are required to get the purified yeast extract.

Yeast extract contains all the natural macromolecules originally present inside the yeast cell. It's rich in macronutrients like carbohydrates and proteins and micronutrients like minerals and vitamins. Among vitamins, yeast extract is high in B vitamins.

Proteins make up almost 65% of the content in the yeast extract. These proteins are made up of amino acids — nutrients that give yeast extract its unique flavor. According to the Food and Agriculture Organization (FAO), yeast extract contains important proteins and amino acids that are similar in quality to those in milk and eggs. However, they may not be able to fulfill your daily protein requirement as most food products contain only minimal amounts of yeast extract. 

One of the most essential amino acids in yeast extract is glutamic acid. It's also found in different foodstuffs like vegetables, fish, meat, and dairy products, as well as soy sauce and parmesan cheese.

The sodium salt of glutamic acid — called glutamate — makes up almost 5% of yeast extract's nutrient content. Many manufacturers extract this glutamate and use it as an additive in food products to give them the distinct "umami" taste — a savory flavor normally associated with mushrooms and meats. You may often find this isolated form of glutamate listed as monosodium glutamate (MSG) in various food items.

Yeast extract is very popular owing to its unique umami flavor. Due to its amino acid profile, many also find the taste of yeast extract similar to that of homemade bouillon. Thanks to such great taste and rich protein content, manufacturers like adding it to various kinds of food items. 

You can find yeast extract used as a flavoring agent in many snack foods, sauces, dressings, gravies, canned soups, soup mixes, broths, meat products, seasoning, dairy products, sweet products, frozen dinners, beverages, and ready-made meals.

In Britain and Australia, it's commonly used in sandwich spreads like Vegemite and Marmite. 

Since it has high vitamin B content, you can also find yeast extract in many nutritional supplements for pregnant women and those with malnutrition. 

The United States (US) Food and Drug Administration (FDA) has given brewer's, or baker's yeast extracts the "generally recognized as safe" (GRAS) status. It is approved to be used as a flavoring agent and additive at levels not exceeding 5% of the food ingredients. The FDA also approves brewer's yeast to be used as a dietary supplement due to its high vitamin B content. 

However, the Center for Science in the Public Interest states that certain people should avoid yeast extract. For example, those with hypertension or other issues caused by high sodium intake may want to limit their consumption of products with yeast extract. 

Many manufacturers use autolyzed yeast extract in place of MSG. MSG can cause symptoms like tingling, mild skin flushing, numbness, and headache.

Since yeast extract contains minimal amounts of glutamate, such side effects are unlikely. But if you develop allergic reactions from inhaling fungal molds, you may get similar symptoms after having yeast extract.

Get in touch with a doctor if you get any severe allergic reactions from yeast extract or if the symptoms don't disappear by themselves. 

People sensitive to MSG may also get reactions from the glutamate in yeast extract. To avoid this situation, the FDA has made it compulsory for manufacturers to:

• Mention "yeast extract" separately in the ingredients list rather than keeping it hidden under the label of "natural flavoring" or "additives."
• Avoid saying "No MSG" or "No added MSG" on the label if the product contains yeast extract, autolyzed yeast extract, hydrolyzed yeast, or soy extract.

So, to avoid the consumption of yeast extract, regularly check and choose products that don't mention it as their ingredient.

In reality, however, you may find it hard to do so. 

This is because there are various products with yeast extract, like those belonging to the processed and packaged food category. Those liking snacks, junk foods, or ready-made meals may especially find yeast extract in most things they eat.

So, if you seriously wish to remove yeast extract from your diet — despite being relatively safe — make sure to avoid most processed foods. Instead, choose to eat fresh fruits and vegetables and prepare your meals by yourselves.