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Why do onions turn pink...

post #1 of 6
Thread Starter 

Hey  Ya'll it's been a while...

Missed ya.

Question...What is the science behind why onions turn red when they are being baked? I understand carmelization so what prevents the onion from compeletely carmelizing when in the oven?

Thanks in advance as always...

Frizbee

Do what you do with passion....the rest will fall into place..
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad.
  ~Rev. Run
Our Lives are not in the laps of gods, but in  the laps of our cooks.
  ~Lin Yutang
Reply
Do what you do with passion....the rest will fall into place..
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad.
  ~Rev. Run
Our Lives are not in the laps of gods, but in  the laps of our cooks.
  ~Lin Yutang
Reply
post #2 of 6

Which onions?  

 

Red onions are full of pH sensitive cyoanthins. They turn pinker when exposed to bases and purple-blue when exposed to acids. Or maybe it's the other way around, but they do change color according to pH.

 

I've not noticed the yellow onions I normally use turning pink when they get baked.

post #3 of 6
Thread Starter 

Specifically I was asking about yellow onions.. Yes, why do they turn pink when baked and how do you stop this?

Thanks

Do what you do with passion....the rest will fall into place..
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad.
  ~Rev. Run
Our Lives are not in the laps of gods, but in  the laps of our cooks.
  ~Lin Yutang
Reply
Do what you do with passion....the rest will fall into place..
Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad.
  ~Rev. Run
Our Lives are not in the laps of gods, but in  the laps of our cooks.
  ~Lin Yutang
Reply
post #4 of 6

They are simply put, Bleeding. When subject to a high dry temp they are on the road to the sugar content caramelizing. This lite caramelzation will appear pink in particular on thick skin sweet onion. It will not hurt the product but will give a weird color.

Chef EdB
Over 50 years in food service business 35 as Ex Chef. Specializing in Volume upscale Catering both on and off premise .(former Exec. Chef in the largest on premise caterer in US  with 17 Million Dollars per year annual volume). 
      Well versed in all facets of Continental Cuisine...

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Chef EdB
Over 50 years in food service business 35 as Ex Chef. Specializing in Volume upscale Catering both on and off premise .(former Exec. Chef in the largest on premise caterer in US  with 17 Million Dollars per year annual volume). 
      Well versed in all facets of Continental Cuisine...

Reply
post #5 of 6
Doesn't it also have something to do with the pan they are being baked in? I believe this will happen when baking them in an aluminum pan but I could be wrong on that. Great question and glad your back at ChefTalk.
Thanks,

Nicko 
ChefTalk.com Founder
All About Braising: The Art of Uncomplicated Cooking
All About Braising: The Art of Uncomplicated Cooking
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Thanks,

Nicko 
ChefTalk.com Founder
All About Braising: The Art of Uncomplicated Cooking
All About Braising: The Art of Uncomplicated Cooking
Bacon (I made)
(26 photos)
Reply
post #6 of 6

Nicko ! I have seen it in a black roasting pan and on a aluminum sheet pan and a ss bain marie insert.

Chef EdB
Over 50 years in food service business 35 as Ex Chef. Specializing in Volume upscale Catering both on and off premise .(former Exec. Chef in the largest on premise caterer in US  with 17 Million Dollars per year annual volume). 
      Well versed in all facets of Continental Cuisine...

Reply

Chef EdB
Over 50 years in food service business 35 as Ex Chef. Specializing in Volume upscale Catering both on and off premise .(former Exec. Chef in the largest on premise caterer in US  with 17 Million Dollars per year annual volume). 
      Well versed in all facets of Continental Cuisine...

Reply
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