Rennet
Rennet (/ˈrɛnɪt/) is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a lipase.
Rennet has traditionally been used to separate milk into solid
Molecular action of rennet enzymes
One of the main actions of rennet is its protease chymosin cleaving the kappa casein chain.[2] Casein is the main protein of milk. Cleavage removes the slightly negatively charged glycomacropeptide (GMP) from the surface of the casein micelle. Because negative charges repel other negative charges, the GMP prevents casein micelles from adhering to each other. With the GMP removed, the casein micelles can begin to cluster and lose their polar charge, causing them to rise out of the polar water molecules and join non-polar milk fat as a portion of the cheese curd. This action is enhanced in the presence of strong ions like those formed from calcium and phosphate. As such, those chemicals are occasionally added to supplement pre-existing quantities in the cheese making process, especially in calcium phosphate-poor goat milk. The solid truncated casein protein network traps other components of milk, such as fats and minerals, to create cheese.[citation needed]
Extraction of calf rennet
Traditional method
Dried and cleaned stomachs of young calves are sliced into small pieces and then put into salt water or whey, together with some vinegar or wine to lower the pH of the solution. After some time (overnight or several days), the solution is filtered. The crude rennet that remains in the filtered solution can then be used to coagulate milk. About 1 gram of this solution can normally coagulate 2 to 4 litres of milk.[5]
Modern method
Deep-frozen stomachs are milled and put into an enzyme-extracting solution. The crude rennet extract is then activated by adding acid; the enzymes in the stomach are produced in an
One kilogram of rennet extract has about 0.7 g of active enzymes – the rest is water and salt and sometimes
Alternative sources
Because of the limited availability of mammalian stomachs for rennet production, cheese makers have sought other ways to coagulate milk since at least Roman times. The many sources of enzymes that can be a substitute for animal rennet range from plants and fungi to microbial sources.[8] Cheeses produced from any of these varieties of rennet are suitable for lactovegetarians, as well as those keeping Kosher. Fermentation-produced chymosin is used more often in industrial cheesemaking in North America and Europe today because it is less expensive than animal rennet.[9]
Vegetable
Many plants have coagulating properties.
Microbial
Some molds such as
The traditional view is that these coagulants result in bitterness and low yield in cheese, especially when aged for a long time. Over the years[when?], microbial coagulants have improved greatly, largely due to the characterization and purification of secondary enzymes responsible for bitter peptide formation/non-specific proteolytic breakdown in cheese aged for long periods. Consequently, it has become possible to produce several high-quality cheeses with microbial rennet.[14]
It is also suitable for the elaboration of
Fermentation-produced chymosin
Because of the above imperfections of microbial and animal rennets, many producers sought other replacements of rennet. With genetic engineering it became possible to isolate rennet genes from animals and introduce them into certain
Originally created by biotechnology company
The most widely used FPC is produced either by the fungus Aspergillus niger and commercialized under the trademark CHY-MAX[22] by the Danish company Chr. Hansen, or produced by Kluyveromyces lactis and commercialized under the trademark Maxiren by the Dutch company DSM.[23]
FPC is chymosin B, so it is purer than animal rennet, which contains a multitude of proteins. FPC provides several benefits to the cheese producer compared with animal or microbial rennet: higher production yield, better curd texture, and reduced bitterness.[16]
Cheeses produced with FPC can be certified kosher[24][25] and halal,[25] and are suitable for vegetarians if no animal-based alimentation was used during the chymosin production in the fermenter.[citation needed]
Nonrennet coagulation
Many soft cheeses are produced without use of rennet, by coagulating milk with acid, such as citric acid or vinegar, or the lactic acid produced by soured milk. Cream cheese, paneer, rubing, and other acid-set cheeses are traditionally made this way. The acidification can also come from bacterial fermentation such as in
Vegan alternatives to cheese are manufactured without using animal milk but instead use soy, wheat, rice or cashew. These can be coagulated with acid using sources such as vinegar or lemon juice.[26][27][28][29]
In mythology
In Yazidism, the Earth is believed to have coagulated and formed when rennet flowed from the White Spring of the celestial Lalish in heaven into the Primeval Ocean.[30]
See also
References
Footnotes
- ^ Yacoubou, Jeanne. "An Update on Rennet". The Vegetarian Resource Group. Retrieved 2021-12-24.
- ^ "Rennet in cheese - the science: How rennet works". 2013-06-12.
- ISBN 9789290532736.
- ^ Singley, Nora. "What You Might Not Know: Not All Cheeses Are Vegetarian!". Kitchn. Kitchn.com. Retrieved 30 January 2022.
- ISBN 978-1-4051-7164-9.
- ^ "Cheese Technology: Lesson 14. CALF RENNET: PREPARATION AND PROPERTIES". ecoursesonline.iasri.res.in. Retrieved 2021-02-04.
- ^ "Hooked on Cheese: Cheese for Vegetarians". The Daily Meal. 2017-08-31. Retrieved 2021-02-04.
- ^ "TECHNICAL REPORT OF EFSA: Explanatory Note for the Guidance of the Scientific Panel of Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) on the Submission of a Dossier on Food Enzymes: 3.2. Source Materials and Manufacturing Process: Comments/Explanations: Updated on version 2014:EN-579". European Food Safety Authority. 2014-11-14. Retrieved 2015-11-11.
- ^ "Chymosin". GMO Compass. Archived from the original on 2015-03-26. Retrieved 2011-03-03.
- ISBN 978-0-12-263652-3. Retrieved 2009-05-06.
- ^ Mike, Tad, "Capers: The Flower Inside", Epikouria Magazine, Fall/Winter 2006
- S2CID 85375727.
- ISBN 978-1-62106-592-0.
- ^ "Marzyme Microbial Coagulant" (PDF). BMBtrade.it. 2011. Archived from the original (PDF) on 2016-05-03. Retrieved 2017-07-17.
- ^ "How to Know if Your Cheese Is Vegetarian Friendly". The Spruce Eats. Retrieved 2021-10-23.
- ^ ISBN 978-1-4051-8298-0.
- ^ "FDA Approves 1st Genetically Engineered Product for Food". Los Angeles Times. 24 March 1990. Retrieved 1 May 2014.
- ^ Staff, National Centre for Biotechnology Education, 2006. Case Study: Chymosin
- ^ "Food Biotechnology in the United States: Science, Regulation, and Issues". U.S. Department of State. Retrieved 2006-08-14.
- ^ E. Johnson, J. A. Lucey (2006) Major Technological Advances and Trends in Cheese J. Dairy Sci. 89(4): 1174–1178
- PMID 29153182.
- ^ "Enzymes for Cheese". Chr-Hansen.com. Archived from the original on 2011-11-01. Retrieved 2012-07-30.
- ^ "DSM Food Specialties — Product Page — Maxiren". DSM.com. Archived from the original on 2012-01-06. Retrieved 2013-01-28.
- ^ "Say Cheese!".
- ^ a b "Chymax spec sheet" (PDF).
- ^ "These 25 Vegan Cheeses Will Make You Quit Dairy Forever". 2017-05-19.
- ^ "12 Vegan Cheese Recipes That Will Change Your Life". Archived from the original on 2017-10-09. Retrieved 2016-05-02.
- ^ "Vegan Cheese Recipes".
- ^ "8 Amazing Vegan "Cheese" Recipes". 12 May 2014.
- OCLC 63127403.
Bibliography
- Carroll, Ricki. Making Cheese, Butter, & Yogurt. Storey Publishing 2003.
- "Biotechnology and Food: Leader and Participant Guide", publication no. 569, produced by North Central Regional Extension. Printed by Cooperative Extension Publications, University of Wisconsin-Extension, Madison, WI, 1994. Publication date: 1994. Tom Zinnen and Jane Voichick
External links
- Fankhauser's Page on Rennet history and use
- Appendix D - Assessment of filamentous fungi - Qualified Presumption of Safety
- FDA-registration of recombinant chymosin
- Recombinant Chymosin
- Cheese Yield Experiments and Proteolysis by Milk-Clotting Enzymes
- Validation of recombinant and bovine chymosin by mass spectrometry
- Native and Biotechnologically Engineered Plant Proteases with Industrial Applications