Summary

• Mushrooms have a deliciously rich savoury flavour called ‘umami’.
• Much of the umami flavour comes from the natural glutamates in mushrooms.
• The umami flavour of mushrooms can replace some of the salt used in recipes.
• Consuming less salt and fewer salty foods helps to keep blood pressure levels normal.

The unique mushroom flavour

Mushrooms have a deliciously rich, savoury flavour, much loved by consumers, chefs and cooks the world over. What is it that makes mushrooms so tasty? It is the natural glutamates in mushrooms that give them their deep flavour, making them a favourite with meat eaters and vegetarians alike. 

Glutamate is an amino acid that is found in all foods with protein. Glutamate is also produced by the body, with high levels in the muscles and the brain. Glutamate is used as a neurotransmitter in the brain by half of all nerve cells.

The glutamate level in the mushroom increases as the mushroom matures from a button to a flat mushroom. Natural glutamate is also responsible for much of the flavour in Parmesan cheese, soy sauce, anchovies, tomato juice, Vegemite and Marmite.  

When extra glutamate is added to food, the salt content can be reduced by 30-40% without affecting the palatability (Mouritsen 2012). We suggest that when you add mushrooms to a meal, you can add far less salt. In fact, you may be able to get away with no salt at all and let the flavour of mushrooms do the talking.

The natural free glutamates in mushrooms are not to be confused with the monosodium glutamate (MSG) sometimes added to foods as a flavour enhancer. There is no MSG in mushrooms.

You can now see why mushrooms are the flavour that everyone enjoys, and they are a very successful substitute for meat. We sometimes consider mushrooms as the meat-eater’s vegetarian choice. It also helps understand why mushrooms complement so many meat dishes.

Potential role of glutamate

Glutamate is a major fuel for the gut. Glutamate is extensively metabolised by enterocytes in the intestines and, therefore, not all of it is absorbed by the gut (Burrin 2009). Glutamate is a signalling molecule in the nervous system of the intestines, and it is thought to signal fullness, or satiety, to the brain helping us to avoid over-eating. Free glutamate may also be absorbed via the stomach and be involved in the digestive function, such as contractile actions of the intestines, gastric acid secretion and blood flow. It seems that glutamate is doing more than providing flavour; it may be regulating our appetite as well.

Blood pressure

If you want to keep your blood pressure healthy then the standard advice is to be fit, keep your weight healthy and avoid highly salted foods. The salt in foods is known as sodium chloride, with the sodium part contributing to high blood pressure. Food labels list sodium and foods with less than 120 mg of salt per 100 grams are considered to be low salt food.

Potassium is a natural mineral in plant foods, and it plays a major role in maintaining fluid and electrolyte balance. A diet with plenty of potassium and low in sodium (salt) appears to both prevent and help correct high blood pressure, which in turn, helps to prevent strokes. The mushroom is very low in sodium and high in potassium, making it perfect for helping to maintain healthy blood pressure.