T Nation

Resistant Starches


#1

In my food chemistry class we were discussing resistant starches and it was said that maltodextrin was a resistant starch. So if a resistant starch acts kind of like dietary fiber but is digested in your Large intestine, then how does is it rapidly absorbed as a polyglucose molecule the way it is said to be used in Surge?

I've been looking it up in various places and it seems that it can be used as a resistant starch in some products and in other products for rapid absorption? But how is this possible? Im confused about this. Any explanation would be helpful.
-Seth


#2

Resistant Starch is any given amount of starch and products of starch degradation that will resist digestion in the small intestine. Maltodextrin, usually made from corn starch is not a Resistant Starch.

However there are other Maltodextrins which are resistant starches made from stuff like debranched retrograded tapioca. There are various uses of these RS's mainly in certain baked products with higher fibre contents and for use to stimulate fecal bifidobacteria. RS's act like insuluble fibre.

Regular Maltodextrin like the stuff used in supplements,(not the same as the special RS variety) were traditionally touted as complex carbohydrates and have a favourable effect on glycaeminc index of foods.

However, maltodextrin has a quite basic and weak structure and is readily absorbed on ingestion. Quite unlike resistant starches. Maltodextrin is abosorbed readily but not as quick as say dextrose.

Hope this helps.


#3

Thanks for the explanation. so if i have it straight there r different types of maltodextrin, the maltodextrins i am discussing in class are the ones from debranched retrograded tapioca and the ones in Surge r not RS and are usually from cornstarch. Thanks for the quick reply and explanation!

-Seth


#4

Yup, there are different grades of maltodextrin. Those found in cheap supplements will tend to act more like sugar in the body where as the ones found in your higher quality (not just price) products will act more like a complex carb.


#5

Woah hang on, you took my info and did some almost journalistic machinations to it !

More to the point, there are different types of Resistant Starches...

I might as well tell you what they are seeing as you sorta misconstrued what I originally told you.

There are four types of resistant starch:

Resistant Starch 1 is physically inaccessible starch that is trapped within cell walls as in some partially milled grains some beans/legumes.

Resistant Starch 2 is resistant starch granules which are found 'naturally' occuring in foods like unripe bananas and some grains.

RS 3 is retrograded or crystalline non-granular starch, for example cooked and then cooled down potatoes, cornflakes and retrograded high amylose maize starch.

RS4 (apart from being a high performance Audi) is a somewhat obscure classification thats specific to chemically modified or re-polymerised starch such as chain linkage altered dextrins.

Debranched retrograded tapioca is an RS4 by the way.

Hope this too helps you.


#6

Okay so I think I understand it all. I just looked in my textbook and there is a whole section on this. Just curious, are you a food chemist or have a degree in something related?
Thanks for all your explanations
-Seth


#7

What textbook you looking at ?
To answer the last bit I have a Degree (BSc Hons) in Food Science and Nutrition, an MSc in Exercise and Nutrition Science, doctorate (Ph.D) in food science also a post graduate diploma in dairy chemistry (PG.Dip).

I did start a first degree in Politics, sacked it off after the first year and swapped to the Food Science.

But I now teach music privately for a living.


#8

My textbook is Foods, experimental perspectives, 5th edition, by Margaret McWilliams.
-Seth


#9

I recommend this book for futher reading..

Experimental Food Science, Third Edition (Food Science and Technology International) by Marj Penfield and Ada Campbell.

and also

Food Science : The Biochemistry of Food & Nutrition, Student Edition by McGraw - Hill.

Neither are that complex, but both are very useful

If you absorb all that then check out also...

Mechanism and Theory in Food Chemistry

by D. Wong.

Gripping bedtime read.