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I've heard that McDonalds and other fast food chains coat their fries in sugar water before frying to aid in color development, but the official McDonalds nutrition information (see page 2) indicates that their fries contain no sugar.

Is there evidence that McDonalds uses sugar to prepare their fries and if so is it just too negligible an amount to show up in the nutritional info?

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It amuses me that, when considering the nutritional information of fries, you skip the fat, sodium and total calories (and even acrylamides) and look for any traces of sugar. –  Oddthinking Jul 19 '11 at 4:03
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The source cited in Wikipedia is (a) not sure if the claim is true about McDonald's fries, (b) is cited in a 1983 book - there has been plenty of changes to the menu in the last 28 years. –  Oddthinking Jul 19 '11 at 4:08
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Fries contain enough starch and other carbohydrates that get turned into sugars in the body that any small amount that might be added to them would have no effect. Also, McD wouldn't lie about their product content, as that'd make them liable to be sued to destruction, so if they don't list it it's not in there. Of course a careless worker might spill something, causing contamination, but all the workplaces I've seen at McD don't have any sugar near the station where the fries are prepared (and are kept meticulously clean). –  jwenting Jul 19 '11 at 5:26
    
the wikipedia article furthermore states a competitor claiming to "assume" that McD does it based on the fact that his company does it. Hardly an authorative claim. And to add insult to injury the article claims that changing the cooking fat reduces cholesterol but goes on to say the same change causes an increase in cholesterol :) –  jwenting Jul 19 '11 at 5:28
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@Oddthinking Interesting observation, although I just figured I didn't need a group of skeptics to prove me that fries are cooked in oil, seasoned with salt, or calorie dense. :) –  Adam Wuerl Jul 19 '11 at 11:29

2 Answers 2

up vote 49 down vote accepted

A small amount of sugar is used to even out the appearance - to ensure an even quantity of reducing sugar is available for Maillard's reaction to proceed equally everywhere (see Wikipedia link for more info). However, the amount does not affect significantly the taste or nutritional values of the fires.

[Washing the potatoes with slightly sugary water] It’s not done for flavouring and it doesn’t mean you’re eating additional sugar.  In fact, total sugar represents approximately .007% per pound of potato, so it’s an extremely small part of the finished product.

McDonald's Australia

Regarding the common claim that the fries are sweet because of this, there is, in fact, evidence of the contrary.

Sugar, when exposed to high temperatures such as that of the oil blend that McDonald's uses when frying, caramelises.

Creme-Caramel
The dark brown colour at the top of a creme-caramel is due to caramelisation of sugar

Fast food fries are most definitely not caramelised. The browning of the chips is through Maillard's reaction and not caramelisation.

Chips
The light brown colour of French fries is due to Maillard's reaction.

Fries are sweet because the starch is first gelatinised during cooking and then broken down into glucose thanks to the amylase enzyme present in our mouth.

Facts and references

  • Oil used by McDonald's to fry: Canola oil
  • Canola oil smoking point: 230˚C
  • Common fry temperature for chips: 200˚C
  • Caramelisation temperature for sugar: 160˚C
  • Maillard's reaction temperature: 154˚C
  • Temperature at which starch gelatinises: 55–85˚C
  • Saliva contains: amylase
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Hu, hu, original research? :) I would have voted this up, even without citation. Everybody should know caramel. –  user unknown Jul 19 '11 at 14:01
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There's a great article on the subject at Serious Eats. The author reverse engineers McDonald's fries: aht.seriouseats.com/archives/2010/05/… –  Ezra Jul 19 '11 at 17:30
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Answers with pictures are so great –  elwyn Jul 19 '11 at 19:45
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Wait, what? Sklivvz doing oroginal research! I'm pleased! +infinity! –  Lennart Regebro Jul 20 '11 at 8:29
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your ref for fry temperature is wrong, and not even relevant to how the fries in question are prepared: a better temperature would be 170°-180°C (this article even mentions 360°F (180°C) for final frying temp) –  ratchet freak Jul 20 '11 at 16:28

Yes.

McDonald's state they they apply sugar to their fries.

This bit below is from the McDonald's Australia website.

Q: Do you add sugar to the fries?

A: We know that you want beautiful, golden brown French fries. Potatoes already naturally contain sugars that, when cooked, can rise to the surface in places and result in unevenly coloured French fries that look light in some areas and dark or burned in others.

All French fries – either those you’d buy in the supermarket or at a restaurant – are sprayed or washed in a solution containing a small amount of sugar which ensures they have an even exterior colour once they’re cooked. It’s not done for flavouring and it doesn’t mean you’re eating additional sugar. In fact, total sugar represents approximately .007% per pound of potato, so it’s an extremely small part of the finished product."

They don't say which sugar they use. One might expect that it is glucose (dextrose) but there are a lot of things that qualify as "sugar".

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Interesting. I could not find a similar question on the US site. I wonder if there are different practices between the countries. –  Adam Wuerl Apr 3 '12 at 11:39
    
Why might one assume that it's glucose? not sucrose? –  Rincewind42 Apr 3 '12 at 15:17
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Nice answer, but I disagree with the initial "Yes". I don't think that "spraying the fries with a solution containing as small amount of sugar" is the same as "coated in sugar", at least not when phrased like this. –  Martin Scharrer Apr 11 '12 at 10:23
    
nor does practice in one country assume it's a global practice. McD adapts their recipes (slightly) to the preferences of the local clientele as well as available raw materials. E.g. afaik the Netherlands is the only country where they offer a vegetarian burger (or at least was the first). –  jwenting Mar 19 '13 at 7:21

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