Starch

[thesloc]

Hello all, I'm new to the forums and I've found a plethora of helpful individuals.

My question is concerning starch.

"The breakdown of starch is often catalyed at very high temperatures (100C). Why is the high temperatue needed?"

I'd appreciate any given help, in detail.


--Thanks.

[Dr.Stein]

Are you sure it is digested/degradated or catalyzed at water-boiling temperature? I think the suitable temperature for digestive system is around body-temperature, which digestive enzyme will work properly. In 100 oC enzymes are damaged so the digestion will not carried out as it should be.

[kjle]

enzymes will denature usually at about 45°C, I think you may be thinking fahrenheit

100°F is much closer to body temperature (98.6°F)

[thesloc]

Hey thanks. The question does say it's Celsius, not Fahrenheit. So I believe the question is a trick question. Now, does anyone know the method by which starch breaks down? Or any idea how I can elaborate further on my question?


How do starch breakdown in the absence of functional enzymes?

I think my problem has something to do with overcoming the activation energy and heat.

[victor]

Starch hydrolysis actually can be done by just heating it with water, as you said, in 100 ºC. But the problem is...how long can you wait for that? keep re-adding water to change the evaporated water vapor and do the iodine test oncee in every 10 minutes......

I ever tried this kind of hydrolysis about 3 days ago. it's an acid catalyzed starch hydrolysis. Just imagine that, 10 mL starch solution, added with 3 mL HCl 3M and heated about 70-80 ºC.....it still need about more than 36 minutes to do a nearly complete hydrolysis...(because I use an iodine test to detect the hydrolysis, while achroodextrine, maltose and glucose share the same result of that test, so I can't say that's a complete hydrolysis of starch).

Breakdown of starch by fuctional enzymes is done by α-amylase and β-amylase. Breakdown by alpha one yields maltose and dextrine, while breakdown by the beta yields maltose. And yes, this enzyme catalyzed breakdown can't be done in 100 ºC due to denaturation by heat.

So, I can say that, if the breakdown of starch is in 100 ºC temperature, it must be acid catalyzed hydrolysis.

@Dr.Stein
Majority enzymes will get denaturated in high temperature but certain enzymes like taq-polymerase and cellulase can stand that heat...

[thesloc]

Thank you Sir.

Something more political:
"In the United Staes, the use of high-fructose syrup dramatically increased after the take-over by the communist regime in Cuba. How can the two events be related?"

Thanks, once again, for any help.

[victor]

who's you calling by 'Sir'?

[Dr.Stein]

@Dr.Stein
Majority enzymes will get denaturated in high temperature but certain enzymes like taq-polymerase and cellulase can stand that heat...

Oh ok, enzyme is not my major, I do not know any exceptions thank you for telling me this

[canalon]

Think agricultural producton of cuba. Tobacco is not the oly thing...

[mith]

High fructose syrup is made from corn

[MrMistery]

and cuba grows sugar..