Questions tagged [carbohydrates]

Carbohydrates are one of three classes of primary metabolites and thus natural products. They are polyhydroxylated hydrocarbons and their derivatives. Colloquially, they are known as sugars. This tag may be applied to all questions that concern carbohydrate species in solution, reaction mechanisms and structures.

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583 views

Are all carbohydrates a subset of alcohols?

According to the definition, an alcohol is any organic compound in which the hydroxyl functional group (-OH) is bound to a saturated carbon atom. Monosaccharides such as glucose contain several ...
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How can 32 g of Gatorade powder contain 33 g of carbohydrates?

A screenshot of the nutrition facts of a can of Gatorade powder was posted on my Facebook feed: The label reads "Per 32 g (about 3 tbsp)", but if you read through the ingredients, the amount of ...
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What is the density of carbohydrates/protein/fat? [closed]

As in weight per volume? I mean.. you always see them specified by weight but they have to have a volume, right? I suppose different fat(for example) molecules would have different densities but then ...
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How to Convert Sucrose to Glucose and Fructose

If you have some sort of sports drink that contains sucrose, how would you take that sucrose and break it down into its components, glucose and fructose? I know that sucrose + water will break it ...
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Carbohydrate conformations

I have to questions regarding the conformations of carbohydrates. There are 38 different conformations for an aldohexose or ketohexose, including $\alpha$ and $\beta$ anomers, namely 2 chairs, 6 ...
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Carbohydrate configurations

I want to study several carbohydrates that includes but not limited to the following molecules: Glucose Galactose Mannose Fructose Tagatose Sorbose I know that for any carbohydrate, possible list of ...
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Why starch (amylose) and cotton (cellulose) are so different?

Both amylose and cellulose have the same "monomer" structure (glucose), so what makes them look/form so differently?
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What are the steps to creating synthetic glucose?

I need to know how to go about creating synthetic glucose with generally available materials. As I am aware of both photosynthesis and glucose in nature, I will not need lessons in how plants produce ...
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In the Haworth projections of D and L glucose, is the stereochemistry at every carbon except the anomeric carbon just inverted?

I'm having a bit of trouble grasping sugar stereochemistry. Using glucose as an example, if you cyclize D and L glucose, is the stereochemistry at every carbon just inverted from the other form? ...
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Periodic cleavage of carbohydrates

Carbohydrate like glucose undergoes periodic cleavage by $\ce{HIO4}$ and forms respective products are five moles of formic acid and one mole of formaldehyde. Here is my question , what is mechanism ...
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How is it that fructose has a different metabolic pathway than glucose but yet glucose is converted to fructose?

Fructose is described to have a different metabolic pathway (a more fat-inducing one) than glucose (see: http://healthyeating.sfgate.com/difference-between-sucrose-glucose-fructose-8704.html) as it ...
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Can paper burn without oxygen or air?

If you put a paper inside an oven vacuum packed and go beyond $250~\mathrm{^\circ C}$, will it burn? There's no oxidizer. If not, what will happen?
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How do you identify reducing / non-reducing sugar by looking at structure?

Identifying reducing / non-reducing sugar been confusing me for a while now , I know that reducing sugar contain aldehyde or ketone group . It's easy to identify them in monosaccharides but this ...
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Is carbohydrate alcohol inebriant?

First of all, though I think that my question is related to this society, if you think reverse, tell me to delete the question: I would like to know if carbohydrate alcohol is inebriant; Can anyone ...
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Maltose Nomenclature

Maltose has a 1,4 glycosidic linkage between two molecules of α-D-Glucopyranose. My textbook suggests the final name of maltose as 4-O-(α-D-Glucopyranosyl)-D-glucopyranose I wanted to know what ...
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Why do gummy bears explode when added to hot potassium chlorate?

This link shows that a gummy bear explodes when in contact with heated potassium chlorate, $\ce{KClO3}$. But what in a gummy bear creates this reaction? Also, do other foods (fruit, icing sugar...) ...
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Can I break starch down into glucose units?

I was wondering if starch can be broken up into individual glucose units. Because on a site I saw, it said that through acid hydrolysis starch can be broken up into amylose and amylopectin. However, ...
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Potassium permanganate oxidation of sugars

I am told that all three sugars below can be oxidized to their corresponding carboxylic acids using potassium permanganate. This strikes me as bloody wrong because only hemiacetal sugars ...
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In water, will sucrose be hydrolysed by water to form glucose and fructose molecules? [duplicate]

If I dissolve sucrose sugar ($\ce{C_12H_22O_11}$) in water, would the water readily hydrolyse the sucrose sugar to form glucose and fructose sugars?
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What is a sugar?

I've always wondered about this... I can look up the exact chemical structure of (say) glucose, which is a sugar. That's easy enough. But what I cannot figure out is this: if I proffer some random ...
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Chemical structure of water-soluble polysaccharide

I don't know much about analytical chemistry, but I need to determine the chemical structure of a water soluble polysaccharide which is not pure and may have D-glucose, mannose and fructose. How do I ...
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1answer
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Why does lactulose turn dark?

Why does the standard 10gm/15ml lactulose solution turn dark when exposed to heat above 30 degrees Celsius? This is probably a simple question. It is funny that the warnings/important information on ...
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1answer
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Is sucrose made of 2 glucose molecules or 1 glucose and 1 fructose? [duplicate]

I have read from several sources about sucrose and some say it is 2 glucose molecules and some others say it is 1 glucose molecule and 1 fructose molecule. I know that both of these are related ...
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Cows milk protein in lactose

Does anyone know if the casein/whey cows milk protein can be found within processed lactose? Some background: our 4-month-old baby was given teething granules. She was then presented with a rash, ...
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Why do other sugars melt whereas sucrose decomposes?

Sucrose decomposes at 186 °C. It doesn’t melt but when it reaches decomposition temperature, sucrose decomposes into fructose and glucose. After cooling and hardening it is no longer sucrose. Am I ...
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Fermentation in beer (reaction schemes)?

I've been struggling with this for a while, and I can't seem to solve the problem. Alcohol is made in the fermentation process in beer: Sugars formed during mashing (maltose and maltotriose) will ...
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1answer
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What the balanced chemical equation for the conversion of starch to dextrin by dry heating?

This question is related to the toasting of bread. When we toast a slice of bread, the starch in it breaks down into dextrin. I want to know the balanced chemical equation for the process.
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Unexpected reaction during acid hydrolysis of cellulose

Recently I tried to hydrolyze some cellulose: I added some acid to it ($\ce{H2SO4}$) then noticed nothing. Even after a few days there was no visible change and after doing some tests for glucose, ...
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Is there a way to turn cellulose into sugar at home?

I know that once you have sugars, you can ferment, distill, and dehydrate to create 95+% ethanol. I've also read about cellulosic ethanol, with the new step there being the breakdown of the cellulose ...
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What chemical properties make some grasses usable for producing textile fabrics?

Textile fabrics are made out of cellulose fibres, that can be derived from cotton or bamboo. As far as I know all grasses contain cellulose, so why are only a few grasses used? What makes them so ...
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How to convert glucose to fructose

How to convert glucose to fructose? Moreover, can there be direct conversion(not necessarily in a single step), or we have to use indirect means, such as from sucrose, or other higher carbohydrates, ...
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What's the difference between alpha-glucose and beta-glucose?

What's the difference between $\alpha$-D-glucose and $\beta$-D-glucose? Are they isomers? Or do they differ in their elemental composition?
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How To Obtain A Reducing Sugar At Home?

I'm looking for a reducing sugar such as glucose or maltose (any reducing sugar will do) for some home chemistry experiments. Is there a readily available reducing sugar that I might source without ...
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Is formaldehyde a carbohydrate?

Formaldehyde has the formula $\ce{CH2O}$, and the ratio of atoms in a simple carb is $\ce{1C:2H:1O}$. This fits the formula of formaldehyde. When I researched this, I found some sources saying that ...
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How would you go about synthesising amino sugars from sugars?

How would you go about synthesising amino sugars from sugars? e.g. How would you synthesise the compound below from D-glucose? Would adding ammonia ($\ce{NH3}$) to it work?
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Which conformer of beta D-glucose is more stable?

I drew the two chair conformers of $ \beta $-D-glucose: Which one is more stable? I think it's the one with all of the OH groups in the equatorial position because of less steric hindrance, but I ...

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