Editing Yeast extract (section)

==Production==
Yeast extracts in general are produced in three steps: fermentation (growing the yeast), disruption (breaking of the cells), and separation (to keep the soluble part). Although the vast majority of yeast extract spreads are made using von Liebig's traditional approach of heat-autolysis using [[by-product|surplus]] yeast from beer brewing, other methods do exist for producing specialized types.<ref name="rg343682745">{{cite conference |last1=Teimouri |first1=Iraj |last2=Ahranjani |first2=Rana Naderi |title=Yeast Extracts: Production, Properties and Application | conference =6th National Conference On Strategic Research in Chemistry And Chemical Engineering With An Emphasis On Indigenous Technology In Iran |date=August 2020 |url=https://www.researchgate.net/publication/343682745}}</ref>

In terms of fermentation, spent beer yeast is commonly contaminated with the bitter compounds from [[hops]], requiring a "debittering" step to wash out most of this undesired flavor. Yeast from other sources are not affected by this issue.<ref>{{cite journal |last1=Nand |first1=K. |title=Debittering of spent brewer's yeast for food purposes |journal=Food/Nahrung |date=1987 |volume=31 |issue=2 |pages=127–131 |doi=10.1002/food.19870310208}}</ref> Spent brewer's yeast is also quite [[biodiverse]], containing yeasts other than traditional ''Saccharomyces cerevisiae'' and sometimes beer spoilage-causing  [[lactic acid bacteria]] too.<ref>{{cite journal |last1=Jacob |first1=Friedrich Felix |last2=Striegel |first2=Lisa |last3=Rychlik |first3=Michael |last4=Hutzler |first4=Mathias |last5=Methner |first5=Frank-Jürgen |title=Spent Yeast from Brewing Processes: A Biodiverse Starting Material for Yeast Extract Production |journal=Fermentation |date=24 June 2019 |volume=5 |issue=2 |pages=51 |doi=10.3390/fermentation5020051|doi-access=free }}</ref>

For disruption of the cell, some physical and chemical methods may be used in place of the heat-autolysis process. Doing so may allow specific compounds to be extracted or to produce an extract without the hydrolysis of cell contents (as in autolysis) happening.<ref name="rg343682745"/> Autolysis can be assisted with added enzymes; for example, additional [[nuclease]] would enhance the release of nucleosides from RNA.<ref name="roempp">{{cite book|isbn=3-13-143462-7|title=Römpp Lexikon Lebensmittelchemie|author=Eisenbrand, Gerhard & Peter Schreier |page=494 f}}</ref>

Separation removes insoluble parts, mainly the yeast's cell wall, from the extract. Cell wall is usually sold in two parts: the glucans as "yeast [[β-glucan]]" and the mannans further processed into [[mannans|mannan]]-oligosaccharide (MOS).<ref>{{cite journal |last1=Baek |first1=KR |last2=Rani Ramakrishnan |first2=S |last3=Kim |first3=SJ |last4=Seo |first4=SO |title=Yeast cell wall mannan structural features, biological activities, and production strategies. |journal=Heliyon |date=30 March 2024 |volume=10 |issue=6 |pages=e27896 |doi=10.1016/j.heliyon.2024.e27896 |doi-access=free |pmid=38524613|pmc=10958358 }}</ref> The product is finally concentrated by drying, into a thick paste or a dry powder.<ref name="roempp"/>