Editing Rancidification (section)

{{Short description|Spoilage of fats & oils into foul-smelling substances}}
{{missing|detection and quantification — peroxide value, acid value, carbonyl value, total polar materials; legal levels|date=November 2021}}
'''Rancidification''' is the process of complete or incomplete [[autoxidation]] or [[hydrolysis]] of [[fat]]s and oils when exposed to air, light, moisture, or bacterial action, producing short-chain [[aldehydes]], [[ketones]] and free [[fatty acids]].<ref name="Ullmann">{{Cite book|doi = 10.1002/14356007.a11_561|chapter = Foods, 3. Food Additives|title = Ullmann's Encyclopedia of Industrial Chemistry|year = 2000|last1 = Lück|first1 = Erich|last2 = von Rymon Lipinski|first2 = Gert-Wolfhard|isbn = 3527306730|publisher=Wiley-VCH|location=Weinheim}}</ref>

When these processes occur in food, undesirable odors and flavors can result. In processed meats, these flavors are collectively known as [[warmed-over flavor]]. In certain cases, however, the flavors can be desirable (as in [[aged cheese]]s).<ref>{{Cite book|doi = 10.1002/14356007.a10_173|chapter = Fats and Fatty Oils|title = Ullmann's Encyclopedia of Industrial Chemistry|year = 2000|last1 = Thomas|first1 = Alfred|isbn = 3527306730|publisher=Wiley-VCH|location=Weinheim}}</ref>

Rancidification can also detract from the nutritional value of food, as some [[vitamin]]s are sensitive to oxidation.<ref name="german">{{cite book|title=Naturwissenschaftliche Grundlagen der Lebensmittelzubereitung|first=Waldemar|last=Termes|publisher=Behr's Verlag|pages=50–37|isbn=978-3-925673-84-9|year=1990|place=Hamburg}}</ref>  Similar to rancidification, oxidative degradation also occurs in other hydrocarbons, such as [[lubricating oil]]s, [[fuel]]s, and mechanical [[cutting fluid]]s.<ref>{{Cite book|doi = 10.1002/14356007.a03_091|chapter = Antioxidants|title = Ullmann's Encyclopedia of Industrial Chemistry|year = 2000|last1 = Klemchuk|first1 = Peter P.|isbn = 3527306730|publisher=Wiley-VCH|location=Weinheim}}</ref>