From Protein Folding to Punjabi Pea Paneer

From Protein Folding to Punjabi Pea Paneer

✿ Making fresh Indian cheese, or paneer, used to be a bit of a production in my home. My mother would start with not-so-fresh milk (why “waste” good milk, was her reasoning), bring it to a boil and then add lemon juice. In fascination, I watched the rapid separation of flocculant white curd from transparently greenish whey. That was my first encounter with the biochemistry of protein denaturation, although I would go on to ruin perfectly good batches of enzymes during my graduate career.

Proteins must be folded properly – into elegant ribbons, twisted helices, graceful loops and tight turns – not only to function properly but also to stay in solution (image 2). Too much heat, salt, acid or any number of adverse conditions cause proteins to unfold just enough to get their sticky inside parts to glom together. In a concerted show of protest, they leave the solution as a precipitate. Which brings us back to cheese. The curd is gathered into cheesecloth and suspended over a bowl to drain, before being packed into a brick under some heavy pots and pans. These days, one just reaches into the freezer of the local Patel Brothers for a perfectly rectangular brick of paneer.

✿ This quintessential Punjabi dish of peas and paneer is called Mattar Paneer. The gravy is vegan, with richness of cashew nuts in place of dairy cream. You can make this dish entirely vegan by replacing the paneer with baby potatoes boiled in their jackets (Alu Mattar..mmm!) or a cheese substitute of your choice.

✿ Recipe, a memorium to a lost G+ friend, and a harrowing tale of protein denaturation from my graduate student days at: https://madamescientist.wordpress.com/2012/12/10/from-protein-folding-to-punjabi-pea-paneer/

#ScienceEveryday  

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154 Responses to From Protein Folding to Punjabi Pea Paneer

  1. Mark Herndon says:


    That’s looks delicio ; )

  2. Yuji Naka says:


    Nice food. Are the diced white cubes chicken or toufu? 


  3. Looks yummy! Those proteins must have been folded really well 🙂

  4. Rajini Rao says:


    Fung Sit , Diced white cubes are fresh, compressed cheese called paneer.

  5. Rajini Rao says:


    Jonas Neergaard-Nielsen , actually they unfolded as a sacrifice to our good taste 😀

  6. Terry McNeil says:


    Homemade fresh paneer, wonderful!! 🙂

  7. Yuji Naka says:


    Rajini Rao Interesting! I will remember “paneer”, next time I will ask for it when I go to Indian restaurant again.   

  8. Rajini Rao says:


    Absolutely! Most Indian restaurants would carry a dish made with paneer. It’s rather rich and bland on its own, so it is usually served with gravy.

  9. Rajini Rao says:


    Thanks, Terry McNeil , have you experimented with paneer?


  10. Ah, me and molecular biology…


    At what stage do the proteins unfold? During the frying?

  11. Yuji Naka says:


    I never tried eating cheese when it’s diced, slightly- fried, and soaked in gravy.. very interesting to me. I’ll definitely try it next time. 


  12. Also, I never had paneer – how does it compare to something like tofu or feta?

  13. Rajini Rao says:


    Danke, Franz Forstmeier .


    Jonas Neergaard-Nielsen , the proteins denature when the lemon juice (or vinegar) is added to hot milk. That’s when they fall out of solution and form the cheese. The “curd” is then collected and packed under a weight. All cheese begins with a denaturation step. 

  14. Yuji Naka says:


    Jonas Neergaard-Nielsen Is it denaturing in deep fry? xD

  15. Terry McNeil says:


    Rajini Rao I’m a huge fan of paneer, it’s so versatile, goes with almost anything.


  16. No clue, Fung Sit – it’s the first time I hear that word! 🙂

  17. Keith Keber says:


    OMG, I am SO glad I added you to my circles!

  18. Rajini Rao says:


    Denaturation or the unfolding of proteins is the most common problem that any scientist working on enzymes has to deal with. The term PhD has been humorously defined as Protein Has Denatured by woeful graduate students 🙂


    Unlike DNA, proteins lose their structure and degrade very easily.

  19. Yuji Naka says:


    Jonas Neergaard-Nielsen I just looked it up, denaturing is essentially unfolding .. so, never mind. I just remember it also has to do with unsaturated fat or something. (forgot when not using them..) 


  20. Okay, doing some reading up on this (apparently quite basic!) stuff.


    The Wikipedia article says “Although denaturing egg whites is irreversible, in many other cases denaturing is reversible.”


    Is it reversible for cheese, paneer, tofu etc.? Melting cheese of course makes it liquid, but it’s not exactly soluble I guess.

  21. Rajini Rao says:


    Fung Sit  Hmmm, unsaturated fat? Perhaps you are thinking of “clarifying” butter…you heat unsalted butter until the milk proteins denature and sink to the bottom. Then you decant off the liquid butter and it stays fresh at room temperature for a long time because the proteins have been removed by denaturation. It also will not burn as easily as butter. Indians call this “ghee” or simply clarified butter.

  22. Yuji Naka says:


    Rajini Rao I did think of butter XD  (thought it was one of the steps making margarine, maybe I’m wrong.)

  23. Rajini Rao says:


    Jonas Neergaard-Nielsen , it is reversible only if the method of denaturation is quite gentle and if the protein is sturdy by evolutionary design. For examples, antibodies are purified in lab by a step of acid denaturation…even so, they are rapidly neutralized so that they refold. Antibodies are designed to be tough and long lasting. Proteases…that chew up other proteins, are quite resistant to denaturation, that’s how they can be added to awful things like laundry detergent. 


    Unfortunately all the cool proteins (i.e., ones I work with 😉 denature if you so much as look at them 😛

  24. E.E. Giorgi says:


    love this post so much!!  yum, wish I could have a taste, too… ok, I’ll content myself with the beautiful pictures… 🙂


  25. Rajini Rao your posts make me hungry, too. 🙂


  26. Rajini Rao For how long you have the coagulated milk under pression?


    If the pression is not much, and the time is short (just put it into a cotton cloth and press it a little so excess water is drained, and let it rest for some minutes, maybe a few houres) it’s called in Catalan “mató” and it’s a very traditional dessert eaten with honey (mel i mató) or maybe honey and nuts.


    Here you can see it: http://www.receptes.cat/recepta1072/mato


    By the way, my mother used to do it when milk got spoiled 🙂


  27. Stop it Rajini Rao 🙂  I am becoming distracted with hunger. Nice post.


  28. Rajini Rao Actually, it turns out that many proteins can be refolded even if they are catastrophically denatured.


    Many crystallography projects start from insoluble protein that must be treated before it regains proper structure and function.

  29. Rajini Rao says:


    Víktor Bautista i Roca , cheese is not pressed for very long. Softer versions can be crumbled in to the dish. There are sweet versions as well. I’m checking out your link, thanks!


    Yes, my mother made it with spoiled milk but I’m too squeamish to do that 🙂

  30. Jim Carver says:


    Víktor Bautista i Roca What are you talking about? pression? There is no such word.


  31. Well, apparently you have to be a prima-donna to be cool in the protein world 🙂

  32. Rajini Rao says:


    Jonas Neergaard-Nielsen , paneer does not taste like tofu and does not have the tang of feta. Perhaps most like fresh mozzarella? Víktor Bautista i Roca has a Catalan equivalent. 


    Fung Sit , I thought margarine was simply hydrogenated vegetable oil (the double bonds between carbon atoms are “saturated” and converted to single bonds with hydrogen). I looked at recipes, and many do have a step with milk and vinegar added. So I’m guessing some protein denaturation is involved. 

  33. Rajini Rao says:


    Jonas Neergaard-Nielsen , prima donna proteins, LOL.


    I work with membrane proteins, Vladimir Vigdorovich , and they are particularly painful. Refolding of proteins by dialysis, right? Probably denature them with urea instead of heat or acid?


  34. Jim Carver There is such word:


    «Pression Pres”sion, n. [L. pressio: cf. F. pression. See 4th Press.]


    1. The act of pressing; pressure. . –Sir I. Newton.


    [1913 Webster]»

  35. Jim Carver says:


    Rajini Rao That’s right about the trans fatty acids, they were/are heated and hydrogen was bubbled in, in the presence of a catalyst. I think it was platinum although other metals may have been used.


  36. Rajini Rao Ahh, membrane proteins … my condolences 🙂


    Dialysis or dilution, either works well. Denaturants are either urea or guanidine hydrochloride with a bunch of reducing agents. Fun stuff.


    The key is that despite folding complexity, many unexpected manipulations work remarkably well and allow us to study this fascinating material. Well … sometimes … when it works. 🙂

  37. Mike Byrnes says:


    Rajini Rao I love your combination of prose, chemistry, exotic food and culture. Delightful to read on a cold Saturday. Thx for transporting me for a moment.

  38. Jim Carver says:


    I agree Mike Byrnes she’s a gem. I think we should keep her even if she does get a little de-natured sometimes. 😉

  39. Rajini Rao says:


    Why, thank you both Mike Byrnes and Jim Carver . I’m quite unfolded by your compliments

  40. Jim Carver says:


    No problem and if you get coagulated…well that’s personal and none of my business! 🙂 Sorry, I just couldn’t wait to drop that into a line fold. Oh god, I seem to be digging myself a hole. help!

  41. Sinya Nakata says:


    I like the Indian dish. There are fewer shops to eat lightly at noon in Japan.

  42. Mike Byrnes says:


    Jim Carver I got myself into that infinite pun loop with Rajini Rao a week ago. Im just now able to write without pun-tificating.


    …Help Im slipping into …

  43. Samia Elsaid says:


    Sounds like a good dish.guess I ll try it one day Rajini Rao

  44. Jim Carver says:


    Mike, she is formidable and we get into it too. She usually wins, but I’ve gotten some good ones in.

  45. Rajini Rao says:


    A veritable punderstorm, as I recall Mike Byrnes . It’s a wild ride down a protein helix, with all those kinks and turns. 


    (Helix, kink and turn are real terms in protein structure, BTW). 

  46. Jim Carver says:


    You guys ever play that game where you try and fold proteins? Oh man, that will bend your brain.

  47. Rajini Rao says:


    Oh yes, the Fold-It game from the folk at UWashington. It gets a lot of popular press coverage. I think it is a fun way to reach the public although hard core biophysicists may not think so. 

  48. Mike Byrnes says:


    Rajini Rao Jim Carver It’s been punderful but I have to call my Punders Anonymous sponsor before I fall into bad company.


  49. Rajini Rao I can’t speak for hard-core biophysicists, but the Baker group seems to be the best at de novo structure prediction (built that reputation over many years). I thought Fold-It was a brilliant way to gamify the process.


    They (the Baker group) actually learned something in the process, by observing the way “players” create and modify their strategies as a group.


    Here is a post from January when I heard David Baker’s talk on the subject:


    https://plus.google.com/112666022385564474173/posts/GCJTZaDLVzy

  50. Jim Carver says:


    Rajini Rao I have the utmost respect for those that work in that field. I’m basically just a geologist that gets some air time in chemistry sometimes. I had some fun putting together an article on xenobiotic metabolism last week and I actually understand most of it now. Boy that was a stretch.

  51. Liz Krane says:


    *droooooool* So much delicious. Great blog post too! 🙂 I learned what protein denaturation is. So apparently when you cook meat or eggs, that’s also an example of protein denaturation because the heat changes the structure of the proteins! I think?

  52. Jim Carver says:


    Roelf Renkema I wouldn’t try it, too chaotic.

  53. Rajini Rao says:


    Vladimir Vigdorovich , I left an answer on your post. Thanks for the link!

  54. Rajini Rao says:


    Liz Krane , yes..cooking is essentially denaturation. Heat is the most common method, but salting and lemon juice also work. You can “cook” sushi or thinly sliced fish by coating with lemon juice. That is acid denaturation. 

  55. Jim Carver says:


    In the order of chaos it goes like this, from the least to the most: wood -> gas -> electric -> microwaves -> gamma/particles

  56. Jim Carver says:


    Liz Krane And there’s also things like enzymes and bacteria, rennet and buttermilk bacteria are examples of those. They also tend to acidify the mixture also so there is more than one thing going on. 

  57. Kunal Rohit says:


    Oh the thaali!!


    Paneer mutter with paratha?

  58. Rajini Rao says:


    Yes, Kunal Rohit ! Thali and katoris 🙂

  59. Rajini Rao says:


    According to Google Translate, that was “Curd with chive and fresh baked bread”. 


  60. So delicious! I just had matar paneer in lunch.

  61. Rajini Rao says:


    Matar paneer made by a punjabi is going to be better than that made by a southern Indian, Balvinder Ubi 🙂


    With chappatis or pulao?


  62. I can say the same for Dosa and Idli. Rajini Rao But yours look good and we don’t add cream or milk in it. Most of the time the gravy is vegan.

  63. Rajini Rao says:


    Thanks, Balvinder Ubi 🙂

  64. Jim Tipping says:


    Yum, thanks, good to know!


  65. When ever I try to make paneer at home it falls apart making it paneer ki bhurji I have no Idea how the guys who sell it or your mom managed to keep it intact.

  66. Rajini Rao says:


    Leave it in the cheese cloth/cotton cloth draining for a while (time honored method is to tie it to the tap over a bowl in the sink. Let it go overnight. Then, shape it and put the weight on it, still wrapped in cloth. I wonder if the crumbling has to do with fat content? Let me check on line, Sudhanshu Pathania .

  67. Rajini Rao says:


    The lovely ladies from showmethecurry.com (I’m a fan) recommend using whole milk and adding half a tablespoon of flour to the paneer and kneading it before putting the weight on it.


    http://showmethecurry.com/odds-ends/homemade-paneer-indian-cheese.html


  68. Thanks Rajini Rao never thought of adding flour to it. 🙂

  69. Rajini Rao says:


    Only half a tablespoon, don’t add too much. And use whole milk. Hope it works!


  70. Yup I’ll keep it in mind, although its hard to find unadulterated milk nowadays the sellers takeout some of the fat from the milk, and then sell, but definitely I’ll give it a try thanks again for the tip. 🙂

  71. Jim Carver says:


    Sudhanshu Pathania The removal of some of the fat shouldn’t affect the protein content I don’t think. Oh well, maybe a little, but the amount is trivial. 🙂

  72. Rajini Rao says:


    It shouldn’t affect the protein content, I agree Jim Carver . But the fat could help hold the cheese clumps together. If it is too dry, it may fall apart as he experienced.

  73. Jim Carver says:


    Rajini Rao Oh yeah I guess that’s true, the amount of fat globules would make a difference.


    Wonder if you could ameliorate that some way? Without getting gross about it oc. I mean gross literally. I tend to think added oil would be too large and maybe emulsify it.


    But that’s going way too far and I start talking like a lab experiment!

  74. Rajini Rao says:


    Perhaps butter instead of oil? Oil may make it runny. 

  75. Jim Carver says:


    Good idea, put the butter back. Don’t know why I didn’t think of that.

  76. Rajini Rao says:


    Thanks, Shinae Choi Robinson . The cooking album is a poorly disguised excuse to inflict science on the unsuspecting G+ audience 🙂

  77. Rajini Rao says:


    That is so going to be my next hashtag.

  78. Jim Carver says:


    Rajini Rao You know along those lines…I was thinking butter is about the most polar oil we use and I guess that’s what makes it so versatile. The lovely butter, wasn’t so bad.

  79. Tom Lee says:


    Looks so good. I love naan. Reminds me of a Pakistani restaurant in Sunnyvale that makes fresh naan on the spot for $2 each. May have to get some. 🙂

  80. Rajini Rao says:


    Freshly made naan sounds great Tom Lee ! Post a pix on your AIFAD if you do buy it 🙂


    These days you can also buy excellent naan in the freezer section of Indian grocery stores. They reheat really well, and come in various flavors (garlic, paneer, etc.).  

  81. Tom Lee says:


    This place offers three kinds of naan, plain, garlic and onion which they scrape fresh garlic and onion onto the fresh hot naan just being removed from of the clay oven. Delicious, with some curry or i wish if I can get some of your Punjabi Pea paneer that can go with those naan.


    For some reason I like freshly made naan better than the frozen ones.


    Do anything special for this Christmas Rajini Rao ? last year you went to the Tintin movie! This year I will go see The Hobbit.

  82. Rajini Rao says:


    Of course, fresh is going to taste way better than the frozen stuff. I’ve tried to make it at home, but you need blistering hot temperatures of the clay oven (tandoor). I can imagine how delicious it must be with the little bits of onion/garlic on the top, mmm.


    I’m waiting for my daughter to come home for the holidays so we can see The Hobbit together. I’ve heard that the 47 frames per second format gives people headaches, and the quality depends on the theater. It should be fun! 

  83. GS SODHI says:


    DUDH FATAN TE OOH LOK GHABROUNDE HANN, JINAA NU PANEER BANOUNA NAHI OUNDA………

  84. Rajini Rao says:


    GS SODHI , Thanks, but I don’t speak Punjabi. Also, it would help if you did not use all capitals when typing 🙂

  85. Tom Lee says:


    There’s no way the frozen stuff would beat the fresh hot ones that just came out of the tandoor. This place makes it a little creamy too, which I like, they probably put some milk into the dough.


    I posted a couple days ago regarding the 47 fps cinematography utilized by director Jackson in this new The Hobbbit movie. Let’s see who would get dizzy first Rajini Rao .I may stay away from the 3D version.

  86. Rajini Rao says:


    David Haddad , yes I do remember (and that you like ELP Pirates) 🙂

  87. Rajini Rao says:


    I hope so, David. I just read the article in Tom’s link (http://theweek.com/article/index/237247/why-isthe-hobbit-making-some-moviegoers-sick). Apparently, there is a strobe like effect in closeups, but it’s great for distance shots. 


    I think I’ll skip the 3D though. 


  88. Woke up and saw your post Rajini Rao ,now my mouth is watering 🙂

  89. Rajini Rao says:


    David Haddad , I made the usual mistake of assuming that whoever was quoted must be an expert in the field 🙂 This makes me all the more curious about seeing the film. 

  90. Rajini Rao says:


    Good morning, Kershaw Rustomji ! How is your cooking going these days? Any recent visits to Mumbai to partake of chai and samosas? 🙂

  91. J Stasko says:


    Alu Mattar is my all-time favorite Indian recipe….  I did not know its relation with Mattar Paneer. 

  92. Rajini Rao says:


    I wish I could taste Nasi lemak for breakfast as you do, Feisal Kamil (a magically veg version, though). Good Sunday morning to you.

  93. Rajini Rao says:


    J Stasko , Mattar is the word for peas. So Alu Mattar translates to Potatoes and Peas, whereas Mattar Paneer is Peas with Paneer. Other than that, no direct relation although one can make them in the same general way.


  94. Rajini Rao Not much of cooking though i was in Mumbai so had a few good foods 🙂


  95. Feisal Kamil Does the “nasi” in nasi lemak mean coconut? In what language? Some malayo-polinesian one? In Swahili coconut is nazi and it would not be strange if it comes from some malaisian word.

  96. Rajini Rao says:


    It’s Malaysian although Feisal Kamil would know about the exact meaning. It would be pretty cool if nasi was related to nazi. In Hindi, coconut is narial


  97. lol! “a harrowing tale of protein denaturation” !!

  98. Rajini Rao says:


    Google Translate was thinking of our waistlines after eating all that delicious coconut milk rice, no doubt.


    David Archer , you laugh, but having two weeks hard labor end up as a sudden precipitate makes for bad memories 😛


  99. Well, as the saying goes, “if you’re not part of the solution, you’re part of the precipitate!”

  100. Rajini Rao says:


    I thought of that joke too, David Archer 🙂


    There goes our theory, Víktor Bautista i Roca ! 


  101. wow…i am feeling hungry

  102. mahek abbas says:


    wowww…..my favourite dish…


  103. I don’t remember the last time I started a Sunday drooling all the way! I always have something special on Sundays. Can’t Thank You enough Rajini Rao. What photographs! But since I’m a foodie – no; that word doesn’t describe ME properly – I’m a Greedy Bastard. Though I like Sahi Paneer  and Paneer Butter Masala more, I like Mutter Paneer too; but not with plain chapattis. If I HAVE to take it with plain chapatti that chapatti will have to be hot off the tava AND “Makkhan Maarke” on both sides! I prefer Paneer in all it’s curried avatars with either Aaloo Paratha or Butter Nun. Thanks for something else too. I always make the gravy with raw Cashew. Today I’ll roast them before pasting it. And I use some raisin and daalchini in the curry and garnish it with dhania patta, I’ll report back tonight IST.

  104. Arun Shroff says:


    Rajini Rao Looks delicious! The elaborate production routine you describe is exactly how I recall we made it – till we too discovered the convenience of our local Patel bros 😉  And let us not forget that Paneer is also used to make many delicious Indian sweets – with Rosgullas being the most popular. Although they are  probably  too sweet for most American palettes. 

  105. Wong Koewei says:


    looks like roti canai (malaysian local indian food) it sure taste nice


  106. Rajini Rao i love paneer.  i tell westerners to use it more like a tofu & less like a cheese (it won’t melt!)  so nice when the helices behave as they should!  (my notifications are so bad, i just found yours buried somewhere invisibly).  would love it if you would share this with foodies+.

  107. GS SODHI says:


    THANKS………..FOR A NICE FOOD


  108. there is nothing like “desi khana” 🙂

  109. Rajini Rao says:


    Nikhil Mishra , I agree 🙂


    I miss all the variety that I would get in India.

  110. Rajini Rao says:


    Oh really, what? That I miss Indian food?


  111. it means u r not in india ?

  112. Rajini Rao says:


    That’s right…check the About page for information 🙂


  113. Wah! Muh me paani aa gya…


    thanks for uploading such a mouthwatering picture

  114. Manik Tyagi says:


    This is making me hungry.

  115. Azad Agrawal says:


    Rajini ji, I liked this post the MOST. Thanks.

  116. mirza amjad says:


    so nice bahot maze wala khna hae i like

  117. rohit patel says:


    jalasa padi jay jo aavu jamava nu madi jay to


  118. Tasty and Healthy food

  119. Preet Bansal says:


    Tusi tah kamal karti ji


  120. What fun! Iranians chees called paneer.

  121. Anand Brar says:


    Amazing post. Makes me wanna just go home and get the dish prepared by grandma!

  122. Dilip Mehta says:


    Fresh fried onion and garlic


  123. Ooh matter paneer with dahi chapatti very happy and good luck Indian

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