Step 2: Milk

As a biological product, milk contains proteins, the principal milk proteins are known as casein but it also contains other proteins. It consists of 80% casein and 20% whey protein. There are four major types of casein molecules: alpha-sl, alpha-s2, beta, and kappa

Because of the negative charge of the casein, it is dispersed in milk so if we want to make cheese we need to denaturate casein to coagulate it.

Denaturation of milk proteins
When an acid is added to milk, the H+ concentration neutralizes the negatively charged casein micelles. When milk is acidified to pH 4.7, it reaches its isoelectric point (the point at which all charges are neutral) and it forms a precipitate known as acid casein. Cottage cheese and cream cheese manufacture involves an acid precipitation of casein with lactic acid or lactic acid-producing microorganisms. Acid casein is used in the chemical industry and as a glazing additive in paper manufacturing.

Casein also can be coagulated with the enzyme rennin, which is found in rennet (an extract from the stomach of calves)
Do you remember which factors affects proteins? If not, go back to step 1 because rennin as a protein is affected by these factors and is enzymatic activity can change.
Rennin works best at body temperature (37 C). If the milk is too cold, the reaction is very slow, and if the milk is too hot, the heat will denature the rennin, rendering it inactive. The mechanism for the coagulation of the casein by the rennin is different from the acid precipitation of casein. The coagulation of the casein by rennin is a two-stage process. In the first stage, rennin (a proteolytic enzyme which means it acts only on proteins) splits a specific bond in the amino acid chain of the kappa-casein macromolecule converting it into a-para-kappa-casein and a glyco-macropeptide. This causes an imbalance in the intermolecular forces in the milk system, and the hydrophilic (water-loving) macropeptides are released into the whey. Unlike kappa-casein, the parakappa-casein does not have the ability to stabilize the micellular structure to prevent the calcium-insoluble caseins from coagulation. In the second stage, colloidal calcium phosphate (this is and example of other compound affecting proteins) bridges within the casein micellular structure, resulting in the three-dimensional curd structure.
The rennin coagulum consists of casein, whey protein, fat, lactose, and the minerals of the milk, and has a fluffier and spongier texture than the acid precipitate. Rennet is used in the manufacture of cheese and cheese products (nowadays, most of the cheese producers do not use calve rennet because is very expensive they use "vegetable rennet" which is made from microorganisms), and rennet casein is used in the plastics industry.
This molds after a while. :P <br>
I really enjoyed the quality of your instructable; you put in so many pedagogical aids...infographics, glossary, multiple well selected photos on and on. Question; how does pastuerization reduce the calcium content of milk as you state in Step 7?
wonderful instructable, thank you for posting.
ATLANTA (Reuters) - Dozens <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin"><strong>Christian Louboutin</strong></a> of Atlanta public school educators accused of <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin for Sale"><strong>Christian Louboutin for Sale</strong></a> cheating on standardized <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin Outlet"><strong>Christian Louboutin Outlet</strong></a> testing have until Wednesday to resign <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin Cheap"><strong>Christian Louboutin Cheap</strong></a> or be fired, local school officials <a href="http://www.christianlouboutin-discounts.com/" title="Cheap Christian Louboutin"><strong>Cheap Christian Louboutin</strong></a> said on Monday.The city's interim school <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin Heels"><strong>Christian Louboutin Heels</strong></a> superintendent has given educators a three-day window starting on Monday to resign and avoid termination proceedings that will begin Thursday, Atlanta Public Schools spokesman Keith Bromery told Reuters.<br><br>The Georgia <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin On Sale"><strong>Christian Louboutin On Sale</strong></a> Association of Educators (GAE) is advising <a href="http://www.christianlouboutin-discounts.com/" title="Christian Louboutin Sale"><strong>Christian Louboutin Sale</strong></a> its members who have been accused in the <a href="http://www.christianlouboutin-discounts.com/" title="http://www.christianlouboutin-discounts.com/"><strong>http://www.christianlouboutin-discounts.com/</strong></a> scandal not to resign, said Michael McGonigle, legal services director for the advocacy group.&quot;I think the school district is moving much too quickly,&quot; he said. &quot;It <a href="http://www.christianlouboutin-discounts.com/christian-louboutin-shoes-c-6.html" title="Christian Louboutin Shoes"><strong>Christian Louboutin Shoes</strong></a> simply took the investigation's report at face value,&quot; he added, referring to the state report.The GAE will provide legal representation to any member who wants to appeal a <a href="http://www.christianlouboutin-discounts.com/christian-louboutin-boots-c-14.html" title="Christian Louboutin Boots"><strong>Christian Louboutin Boots</strong></a><br> termination, he said.&quot;We think it's worth the fight,&quot; McGonigle said.CONSPIRACY OF SILENCE?The cheating discovered in 2009, found in 44 of the 56 Atlanta public schools examined, was prompted primarily by pressure to meet targets in a data-driven environment, according to a statement released by Georgia Governor Nathan Deal's office earlier this month.
However, former U.S. Ambassador <a href="http://www.nikehighheels.com/" title="Nike High Heels"><strong>Nike High Heels</strong></a> to NATO Robert Hunter--who dealt with <a href="http://www.nikehighheels.com/" title="Nike Heels"><strong>Nike Heels</strong></a> many of the same debates about no-fly-zones and UN resolutions during the Bosnia and Kosovo conflicts in the 1990s--argues that <a href="http://www.nikehighheels.com/" title="Jordan Heels"><strong>Jordan Heels</strong></a> an international intervention in Libya need not be so complex: A no-fly zone can be imposed in a matter of hours, likely with low military risk, as NATO <a href="http://www.nikehighheels.com/" title="Nike Dunk Heels"><strong>Nike Dunk Heels</strong></a> demonstrated over Bosnia in the mid-1990s and as a coalition did over Iraq after 1991. As Gates argued, this might also require <a href="http://www.nikehighheels.com/" title="Jordan High Heels"><strong>Jordan High Heels</strong></a> suppressing Libyan air defenses -- but that is also <a href="http://www.nikehighheels.com/" title="Dunk Heels"><strong>Dunk Heels</strong></a> a relatively straightforward military proposition. In sum, the course is clear. Washington should push for the <a href="http://www.nikehighheels.com/" title="Air Jordan Heels"><strong>Air Jordan Heels</strong></a> rapid institution of a no-fly zone against the Qaddafi regime. This no-fly zone could be undertaken by NATO, the European Union, or by a &quot;coalition of the willing&quot; that includes the United States, France, the United Kingdom, and a few others.
The recalls spanned more than 10 million <a href="http://www.talluggbootssale.com/ugg-classic-mini-c-6.html" title="UGG 5854"><strong>UGG 5854</strong></a> vehicles around the world for faulty floor mats, sticky gas pedals, software glitches and other defects, but mostly in North America. Toyota <a href="http://www.talluggbootssale.com/ugg-classic-tall-c-1.html" title="UGG Classic Tall"><strong>UGG Classic Tall</strong></a> was the only major automaker to see its North American vehicle sales drop last year compared to <a href="http://www.talluggbootssale.com/ugg-classic-short-c-4.html" title="UGG 5825"><strong>UGG 5825</strong></a> the previous year. Other automakers staged a recovery from the global financial crisis. Toyota's North American sales last year totaled 1.94 million vehicles, down 2 percent from 2009, with 1.76 million of that total in the U.S. <br><br><a href="http://www.talluggbootssale.com/ugg-classic-short-c-4.html" title="UGG Classic Short"><strong>UGG Classic Short</strong></a><br><a href="http://www.talluggbootssale.com/ugg-classic-short-c-4.html" title="Classic Short UGGS"><strong>Classic Short UGGS</strong></a><br><a href="http://www.talluggbootssale.com/ugg-classic-short-c-4.html" title="Short UGG Boots"><strong>Short UGG Boots</strong></a><br><a href="http://www.talluggbootssale.com/ugg-bailey-button-c-3.html" title="UGG Bailey Button"><strong>UGG Bailey Button</strong></a><br><a href="http://www.talluggbootssale.com/ugg-bailey-button-c-3.html" title="Bailey Button UGG Boots"><strong>Bailey Button UGG Boots</strong></a><br><a href="http://www.talluggbootssale.com/ugg-bailey-button-c-3.html" title="UGG Button Boots"><strong>UGG Button Boots</strong></a><br><br>Toyota fared better in its home <a href="http://www.talluggbootssale.com/ugg-bailey-button-c-3.html" title="UGG 5803"><strong>UGG 5803</strong></a> Japanese market, where tax <a href="http://www.talluggbootssale.com/ugg-classic-tall-c-1.html" title="UGG Tall Boots"><strong>UGG Tall Boots</strong></a> breaks and government incentives for green vehicles kept its Prius gas-electric hybrid sales <a href="http://www.talluggbootssale.com/ugg-knightsbridge-c-55.html" title="UGG Knighstbridge"><strong>UGG Knighstbridge</strong></a> booming. The Prius ranked as Japan's top-selling car in 2010 with <a href="http://www.talluggbootssale.com/ugg-knightsbridge-c-55.html" title="UGG Knighstbridge Boots"><strong>UGG Knighstbridge Boots</strong></a> nnual sales of 315,669 cars, hitting an all-time high for any nameplate and a 51 percent increase from the previous year. Toyota's sales in Japan jumped 10 <a href="http://www.talluggbootssale.com/ugg-knightsbridge-c-55.html" title="UGG 5119"><strong>UGG 5119</strong></a> percent last year to 2.20 million vehicles, despite a sluggish economy.
do you have to have remmet and calcium chloride? can u use somthing else
heat the milk till it's near boiling and add lemon. kill the flame and cover for 30 minutes, cut up the curds and continue with step 10
Great 'ible. I've been reading about the health benefits of whey protein (claims for muscle building/maintaining, insulin regulation, etc.) Instead of, or in addition to, ricotta, could the whey liquid be processed into a "sports drink"? How much protein would it contain?
Thank you for the instructable! Quick question: Where can I find calcium chloride locally? I know it's available online, but where can I go pick it up in a store? I live in Northern California, of course, my town probably looks very much like your town. Your anticipated wisdom and knowledge is greatly appreciated! :)
I got my liquid calcium chloride, natural rennet and vegetarian rennet from <a rel="nofollow" href="http://www.cheesemaking.com/">http://www.cheesemaking.com/</a><br/>
here's a source of calcium chloride and other things<br/><a rel="nofollow" href="http://glengarrycheesemaking.on.ca/index.htm">http://glengarrycheesemaking.on.ca/index.htm</a><br/>
An amazing job- I especially like the use of a glossary for individuals like myself that are a bit lacking in the necessary knowledge base. :P
That was an intense tutorial! I'll have to try it.<br/><br/>Check <a rel="nofollow" href="http://www.instructables.com/id/EN6AXM0YAOEV2Z6A2R/">here</a> for info on inserting clean-looking links.<br/>
Thank you, now the links look is better

About This Instructable


97 favorites


Bio: Food Chemist with a desire to study Entomology some day. Hobbies: Cooking, origami, reading, watching anime, my crazy pigeon and sometimes videogames.
More by syribia: When pigs have wings pop up card Pocket paper kaleidoscope toy Anti stress balls
Add instructable to: