The Three Browning Reactions in Food

[00:00] It is common among cooks to refer to any food  browning under heat as "caramelization." People   will say that meat is caramelized when  it gets a good crust on it, or bread.

[00:13] Is this wrong? Well, I think it depends  on what you mean by "wrong." There are   multiple browning reactions that happen in  food and caramelization is but one of them.

[00:28] All the food browning reactions  can be sorted in two categories:   enzymatic and non-enzymatic. Enzymatic  is the kind of browning that happens  

[00:40] when you cut fruit and leave it open  to the air. It's a kind of oxidation. Plants naturally biosynthesize a broad  class of chemicals known as phenols. Phenols are involved in lots of the colors  and smells that attract pollinators to plants,  

[00:58] or attract fruit-eating animals, like  us, who might help the plant reproduce   by taking the fruit somewhere to  eat it and dropping the seeds. When you cut the fruit, you bust through  cell walls and release an enzyme,  

[01:15] which is a kind of protein, called polyphenol  oxidase. You also expose the cut surface to air,   and in the presence of oxygen, polyphenol  oxidase oxidizes the phenols, or chemically  

[01:30] changes them with oxygen into new things  — specifically, in this case, quinones,   which are another class of organic compounds that  are toxic to microorganisms and yucky to insects.

[01:44] Basically, when the plant  is wounded, it produces this   layer of polymerized quinones to  protect itself. It's a band aid. The quinones then react with proteins  and free amino acids in the fruit to  

[02:00] produce a class of brown-colored  compounds known as melanin. Yes,   melanin. The stuff that makes fruit brown  is the same stuff that makes people brown.  

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[03:32] your subscription when you use my link. Join the  millions of Babbel learners breaking the language   barrier every day and Babbel dot come slash Ragusea. cut fruit and leave it out, and none of that  is caramelization. Caramelization is one of  

[03:50] the two non-enzymatic browning reactions in  food, both of which can be observed via this   little 'smores maker toy my kids won at one of  those kiddie casino arcades. We kinda love it.

[04:06] Camelization is something that happens when sugar  meets heat. Only heat and sugar are involved. How much heat is required depends  on the ph of the environment,  

[04:18] and on which sugar you're caramelizing.  In low ph, acidic conditions, fructose   can caramelize at just over the boiling  point, which is not very hot at all. That's  

[04:32] why high-fructose foods are more likely to have  those caramel flavor notes. Glucose caramelizes   at like low-baking temperatures, sucrose  caramelizes at normal baking temperatures.

[04:47] One hypothesis as to why 350ºF/180ºC  is a common default oven temperature   is that's the lowest heat that is  likely to caramelize most sugars,  

[05:00] though maltose needs it a little hotter  than that. And what is this caramelization? Basically it's just the sugars breaking apart and  reforming into a million new organic compounds.  

[05:14] Some of the sugars polymerize, or link together  into giant structures known as caramelans,   caramelens, and caramelins —  solid naming convention there,  

[05:29] science. No opportunity for confusion at all. Anyway, these big sugar polymers  absorb light and so they look brown.   You also get a lot of much smaller, volatile  molecules that easily vaporize and we smell  

[05:46] them. The big one in caramel is called  diacetyl, which smells intensely like butter,   because it's also in butter, and with  massive exposure it's responsible for  

[05:59] the disease known as popcorn lung, but  that's not a real hazard of eating caramel. If you over caramelize sugar with too much  heat you start breaking these compounds down  

[06:11] into chemicals that get gradually  closer and closer to pure carbon,   so the sugar turns bitter  and black. That's burning. The other kind of non-enzymatic browning  in food is the famous Maillard Reaction,  

[06:28] named after the French chemist who first  described it in 1912. He was trying to   replicate the natural process of protein synthesis  in a lab and then he stumbled on this thing. The Maillard Reaction happens when sugar and  

[06:42] amino acids react with each  other in hot, dry conditions. Mashmallow is a great example because it is  a sugar syrup foam stabilized with protein,  

[06:54] like egg white or gelatine,  which provides the amino acids. Between low to middle baking temperatures, the  sugars and proteins break down and parts of them  

[07:06] recombine to make new compounds that are super  unstable and lead to more compounds that are   unstable and a whole crazy chain reaction unfolds  resulting in lots of complex chemicals with  

[07:19] complex flavors. It's really too complicated  to explain in much greater detail here. The particular compounds that create the  brown color are known as melanoidins,  

[07:33] which is to say they're not  melanin but they're like melanin. Some of the compounds created by  the Maillard Reaction smell toasty,   some smell nutty, others taste umami-y,  and it all depends on the specific amino  

[07:50] acids and reducing sugars involved and  the exact heat and the exact conditions. One useful thing to know is that the Maillard  Reaction is enhanced in high ph, or alkaline  

[08:05] conditions. That's why you soak pretzels in  lye, to make them Maillard faster. You get   a super brown thin piece of bread that's still  soft on the inside, because it browned so fast.

[08:18] Acidic, low ph conditions inhibit the  maillard reaction. The more yogurt   you put in your naan dough, the less  it's gonna brown, because of the acid.

[08:31] That's a big difference  compared to caramelization.   Caramelization is enhanced by extreme ph in  either direction, basic or acidic. And that,  

[08:43] alone, may be a good enough reason to keep  these two things linguistically separate. And yet, cooks often refer to  either kind of non-enzymatic   browning as "caramelization," and generally  speaking, I think that's fine, if you care.  

[09:03] Fact is, both kinds of browning are usually  happening when you brown almost anything,   because virtually all foods contain at least  a little sugar and a little protein. Meat is  

[09:18] mostly protein but it naturally contains some  sugar, because animals run on glucose. Onions   contain a ton of sugar, but also some protein,  because all known lifeforms contain protein.

[09:33] The more protein and sugar your food  has, the more browning you'll get. Both Maillard and caramelization are generally  happening in most cooking, it's just a matter of  

[09:46] which is the dominant reaction. But, if you want  to keep yourself out of most trouble, if you want   to immunize yourself against attacks by pedants,  just say "browning." Whether it's caramelization,  

[10:02] maillard, enzymatic browning, just call it  browning. It's all browning. That is all.