Yeast extract

Yeast extract is a common ingredient in commercially prepared soups (canned, frozen, or deli).[1][2] It is a flavor enhancer like monosodium glutamate (MSG).

Yeast extracts consist of the cell contents of yeast without the cell walls;[3] they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savoury flavors and umami taste sensations[4] and can be found in a large variety of packaged foods[5] including frozen meals, crackers, snack foods, gravy, stock and more. They are rich in B vitamins (but not B12). Yeast extracts and fermented foods contain glutamic acid (free glutamates), an amino acid which adds an umami flavor. Glutamic acid is found in meat, cheese, fungi (mushrooms and yeast) and vegetables—such as broccoli and tomatoes.[6][7] A number of other substances found in yeast extract provide aromas, some meat-like, when allowed to react under heat.[8]

The heat-autolytic process to make yeast extract of the autolysate type was invented in the 19th century by Justus von Liebig.[9] Yeast cells are heated until they rupture, then the cells' own digestive enzymes break their proteins down into simpler compounds (amino acids and peptides), a process called autolysis.[10] The insoluble cell walls are then separated by centrifuge, filtered, and usually spray-dried.[11] This is the process used for Vegemite, Marmite, and the like.[12]

Yeast extracts in liquid form can be dried to a light paste or a dry powder. This is not the same as nutritional yeast, which are made from intact cells not directly hydrolyzed and consequently have a lighter flavor.[12]

  1. ^ "Handcrafted chicken soup doesn't happen in 30 minutes, but it can take less work than you might think". National Post. 17 April 2017. Retrieved 27 September 2018.
  2. ^ "Campbell Rethinks Its Soup Recipe as Consumer Tastes Change". The New York Times. 10 November 2015. Retrieved 27 September 2018.
  3. ^ Umami: Unlocking the Secrets of the Fifth Taste. Arts and Traditions of the Table: Perspe. Columbia University Press. 2014. p. 172. ISBN 978-0-231-16890-8. Retrieved 27 September 2018.
  4. ^ Baines, D.; Seal, R. (2012). Natural Food Additives, Ingredients and Flavourings. Woodhead Publishing Series in Food Science, Technology and Nutrition. Elsevier Science. p. 296. ISBN 978-0-85709-572-5. Retrieved 27 September 2018.
  5. ^ Costello, Rose (21 March 2013). "Do you really know what exactly is in your frozen chips?". The Irish Times. Retrieved 27 September 2018.
  6. ^ "Your guide to glutamate (+vegan queso salsa dip)". WhyFoodWorks. Retrieved 15 April 2016.
  7. ^ Renton, Alex (10 July 2005). "If MSG is so bad for you, why doesn't everyone in Asia have a headache?". The Guardian. Retrieved 6 April 2018.
  8. ^ Kale, Prajyoti; Mishra, Anusha; Annapure, Uday S. (June 2022). "Development of vegan meat flavour: A review on sources and techniques". Future Foods. 5: 100149. doi:10.1016/j.fufo.2022.100149.
  9. ^ "Marmite: Profile of a yeast-based spread".
  10. ^ "Here's how food companies sneak MSG into foods". Business Insider. Retrieved 5 April 2018.
  11. ^ George A. Burdock, Encyclopedia of Food and Color Additives 3:2972, CRC Press, 1997, ISBN 0849394147
  12. ^ a b Bond, Owen. "Benefits of Yeast Extract". Livestrong.com. Retrieved 4 April 2018.