Glycaemic index and resistent starch

Glikemijski indeks (GI) određene količine i vrste ugljikohidrata utječe na brzinu promjene koncentracije glukoze u krvi (GUK), a ta promjena povezana je s cijelim nizom bolesti kao što su dijabetes tipa 2, pretilost, metabolički sindrom i kardiovaskularne bolesti. Porast GUK nije određen samo GI neke hrane nego i količinom ali i vrstom ugljikohidrata u toj hranii. Jedan od glavnih izvora ugljikohidrata u svakodnevnoj prehrani ljudi (25 – 50 % ukupnog energetskog unosa) predstavlja škrob koji dolazi iz hrane biljnog podrijetla. Proizvodnja i potrošnja škroba u svijetu je u stalnom porastu. Nativni škrob koji se proizvodi izoliranjem iz biljnih materijala (najčešće kukuruza, tapioke, pšenice, krumpira i riže) ima ograničenu primjenu zbog određenih nedostataka koji se riješavaju kemijskim, fizikalnim i enzimskim postupcima modifikacije škroba. Prema probavljivosti škrob se dijeli u tri skupine, od kojih je s aspekta utjecaja na zdravlje najvažniji rezistentni škrob. Ova se frakcija škroba ne razgrađuje u tankom crijevu i nerazgrađena odlazi u debelo crijevo, gdje se fermentacijom pomoću crijevne mikroflore prevodi u kratkolančane masne kiseline (octena, propionska, maslačna), CO2, vodik i kod nekih pojedinaca metan. Rezistentni škorb ima veliki potencijal u prehrambenoj industriji zbog utvrđenog povoljnog učinka na glikemiju (niži GI hrane) i smanjenog rizika za cijeli niz bolesti (npr. dijabetes tipa 2, kardiovaskularne bolesti, pretilost i karcinom debelog crijeva).Glycaemic index (GI) of a certain quantity and type of carbohydrate affects the rate of change of glucose concentration, which correlates with type 2 diabetes, obesity, metabolic syndrome and cardiovascular disease. The increase in blood glucose is not determined only by the GI of a certain food, but also the amount and the type of carbohydrate. One of the main sources of carbohydrates in a daily diet (25 - 50% of total energy intake) represents starch coming from plant foods. Production and consumption of starch in the world continuously rises. The native starch, which is produced by isolation from plant material (typically corn, tapioca, wheat, potato, and rice), has limited use due to certain disadvantages solved by chemical, physical and enzymatic methods of starch modification. According to its digestibility, starches are divided into three groups, out of which the most interesting from the aspect of health has resistant starch. This fraction of starch is not digested in the small intestine, but undigested enters the colon, where it is fermented by the intestinal microflora and converted into short chain fatty acids (acetic, propionic, butyric), CO2, hydrogen and in some individuals to methane. Resistant starch has great potential in food industry because of the favourable effect on glycaemia (lowers GI of foods) and reduced risk for a number of diseases (e.g. type 2 diabetes, cardiovascular disease, obesity, and colorectal cancer)