Curry Recipes Online
Beginners Guide => Hints, Tips, Methods and so on.. => Cooking Methods => Topic started by: SnS on March 04, 2008, 03:56 PM
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What makes an onion work?
Cut it, and it explodes with strong smells, hot flavours, and irritating vapours. But detonate the firepower, and it can be meek and mild - even sweet. The key is to understand an onion's structure.
With this knowledge, any cook can manipulate this versatile bulb to achieve pleasingly specific results.
Onion structure and onion chemistry
Onions come in many different colours and sizes, but all are the same species. The dry bulbs, the vegetable we're exploring here, are 89 percent water and 8 to 9 percent soluble sugars; the rest is minerals, fats, proteins, and sulphur compounds.
The sulphur compounds produce distinctive flavour and an aroma that can be difficult to disguise once you've eaten or touched onions. These oil-soluble compounds easily remain in the oils on your skin. They're also blood-soluble and so can be detected in breath and perspiration.
Some onion compounds do not form until you break cell membranes. As soon as a cell is broken, as by peeling, bruising, or cutting, a definite sequence of reactions follows. A key component is the enzyme alliinase. The degree to which this enzyme is activated affects the intensity of the response.
First, sulphur-containing compounds are produced; these are responsible for irritating vapours, one of which stimulates a tear response, and for a biting astringency. These compounds quickly break down into others, which ultimately yield the onion flavour and aroma. In raw or partially cooked onions, these compounds mask sugars and dominate taste.
How to control onion behaviour
Cutting or breaking the cell membranes develops compounds associated with flavour, aroma, and bitterness. With more disruption, more of these compounds, including lachrymator (tear producer), will be formed. To minimize this effect, peel onions under running water so you rinse away vapours and lachrymator as they are created. Chilling onions before you cut also slows the release of tear producer.
When you chop onions in a food processor, more cells are bruised than when you mince onions by hand--so the flavour is stronger and more bitter.
Cooking time and heat intensity both affect flavour. A short period of high heat brings out strong onion characteristics more quickly. But long cooking over low heat diminishes the strong taste, enhancing the onion's natural sweetness.
Using too high a temperature for too long a time develops bitterness, which is somewhat different from a burnt flavour.
Saute: most flavour (not hot)
Sauteing or stir-frying cut onion over medium-high heat brings out the most flavour. The high temperature volatilizes the first set of compounds, this speeds production of other compounds associated with onion flavour and aroma. Sugars in the onion caramelize, which lends colour and flavour to sauces and stocks.
Slow-cook: sweet, mild, limp
Slow-cook sliced onions in oil over moderate heat until they become very limp and golden. Slicing brings forth flavour components; long gentle cooking dissipates them, unmasking natural sweetness. Some of the soluble onion sugars caramelize during cooking, deepening and enriching flavour.
Whole: mellow and mild
If onion is cooked uncut, hot flavour from its enzyme, alliinase, never develops; you get only mild onion flavour with slight sweetness.
Boil whole: sweet, mild
When small, whole, peeled onions are boiled in water, the onion produces a compound much sweeter than sugar. As with baked whole onions, alliinase's hot flavour doesn't develop.
Deep-fry: crisp, sweet, golden
Cut onion into thin shreds, lightly dust with flour, and fry in a generous amount of oil. The large surface area exposes sulphur compounds. The hot oil drives off many of them and much of the onion's moisture, leaving crisp sweet shreds.
Now you all know about onions!
SnS ;D
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Adding a little salt to your chopped onion will also cut down on the bitterness as it releases the natural sugars.
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Thanks Sns
That explains why any recipe using fried pureed raw onions, tastes so bitter
I have a Pat Chapman recipe using it (I think it was CTM from his first restaurant cookbook)
I thought I did something wrong, but I guess the recipe could never have gone right
Adding a little salt to your chopped onion will also cut down on the bitterness as it releases the natural sugars.
Hi Domi
I noticed how salt affected the sweetness of a base I was cooking
It was one of those "experimental curry base days"
The second base version I made that day,used double the salt
It didn't turn out saltier, just loads sweeter
It does seem strange, doesn't it?
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Some interesting reading about onions on this forum here
http://forums.egullet.org/index.php?showtopic=75013
SnS ;D
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Great post SnS - thanks! ;D
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Thanks for the info SnS! Great stuff! ;D
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Has anyone tried sprinkling their uncooked onion with a quarter teaspoon of asafoetida before frying? I add asafoetida to all my dishes and I think this is the best way to fully make use of the spice, I've added it in the spice mix and after cooking the onion but I really do think it makes more of a difference when added to the onion before it's cooked...
or am I just kidding meself that it works better? :-\
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Hi Domi
I always thought Asafoetida was used instead of onion, but I guess if you use them both together that's gonna create one hell of an onion taste. ;D
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Hi Domi
I guess if you use them both together that's gonna create one hell of an onion taste. ;D
No it doesn't SnS, if anything it makes the fried onion taste more mellow, deeper, or more rounded....I only ever use a quarter teaspoon (or thereabouts) not enough to overpower it in any way, it just enhances the flavour. By the way, asafoetida does stink, but once it hits the onion the farty smell disappears instantly and can't be smelt during the cooking process either. ;) Asafoetida (the plant, not the dried spice) is used as a substitute for onion and garlic, which is why I think it really enhances the flavour....it's a natural marriage for me. :)
More info on asafoetida:
http://www.macasafoetida.com/infozone.asp
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Can anyone tell me some nice herbs or spices I could add while frying my onions to make a chicken tikka have a more flavourful taste? Lately I have found that something is missing.
Also thanks for all this useful infomation on onions it will help me in later dishes.
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Can anyone tell me some nice herbs or spices I could add while frying my onions to make a chicken tikka have a more flavourful taste? Lately I have found that something is missing.
Why are you putting onions in chicken tikka? Sounds odd. Stick to ginger, garlic, spices and yoghurt and you'll be fine
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Here is a text extract from a brilliant cook book 'Classic Indian Cookery' by Julie Sahni. If you haven't got a copy, it is well worth the price tag 9.74 (Amazon). SnS ;)
http://www.amazon.co.uk/Classic-Indian-Cookery-Julie-Sahni/dp/1904010687/ref=sr_1_4?ie=UTF8&s=books&qid=1211152696&sr=8-4
# A word of caution: Onions available here (UK) differ from those available in India. Because the Indian climate is warmer, the onion grown there is pungent and less juicy. This is a crucial difference, because the Indian recipes specify that onions should be ground to a paste before frying. This is impossible to do with our (UK) onions, as they become a puree or watery sauce in the process. Therefore, always finely chop the onions or slice them into thin shreds (never mash) before frying, so that you do not destroy the fibres that contain the moisture.#
So - in a nutshell - the type of onion we use can make a big difference to the final dish.
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It is true that there are advantages of onions. But there are certain things that most if us do not know. There are some ill effects of onions as well.
1. Latex and sulphur are contained in onions.
2. You get tears when cutting the onion because of sulpher in it.
3. The PH of the blood can be reduced because of onions.
4. Can prevent correct absorption of drugs.
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It is true that there are advantages of onions. But there are certain things that most if us do not know. There are some ill effects of onions as well.
1. Latex and sulphur are contained in onions.
2. You get tears when cutting the onion because of sulpher in it.
3. The PH of the blood can be reduced because of onions.
4. Can prevent correct absorption of drugs.
Not entirely convinced by this list !
I'm happy to go along with the sulphur content of onions, but on what authority do you base your claim that they also contain latex ? Also bear in mind that some authorities argue that the sulphur content can be beneficial in combating the formation of cancer cells, reducing hypertension and assisting in the regeneration of hair follicles.
I'd also be interested to know on what authority you base claims 3 & 4 : I'm all in favour of keeping us curry chefs informed of the risks involved, but unsubstantiated claims can be more of a hindrance than a help.
** Phil.
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It sounds like some of thinking presented on this web page:
http://ramjeeawon.info/snp/shree-shree-baba-shree/ill-effects-of-onions-garlic/ (http://ramjeeawon.info/snp/shree-shree-baba-shree/ill-effects-of-onions-garlic/)
I have read that some Indians consider onions and garlic a bit too naughty and I read that these people would use hing as a subsitute.
The bit about sulphur sounds like poor science to me. You could say the same about carbon. Carbon monoxide is a killer of course, but our bodies contain loads of carbon and we couldn't live without it.
Sounds like a load of twaddle to me.
Paul
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A freind of mine used to deliver butcher meat to Indian resteraunts ,he said they used o use a lot of minced onions or pureed onions in their cooking. This may account for the smooth texture in cooking ,anyone heard of this
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A freind of mine used to deliver butcher meat to Indian resteraunts ,he said they used o use a lot of minced onions or pureed onions in their cooking. This may account for the smooth texture in cooking ,anyone heard of this
Well, yes : almost every base of which I am aware contains a large quantity of onions, which (via various techniques) get liquidised/macerated/pulped until what remains is that wonderful smooth base that is the basis (no pun intended) of almost every BIR curry.
** Phil.