Resistant Starch: Nutrition, Functionality, and Health Benefits
Resistant starch (RS) is a unique type of dietary carbohydrate that resists digestion in the small intestine and instead ferments in the large intestine, acting similarly to dietary fiber. It has gained increasing attention in food science and nutrition due to its prebiotic effects, glycemic control benefits, and positive impact on gut health.
What Is Resistant Starch?
Unlike regular starch, which is broken down into glucose during digestion, resistant starch passes through the small intestine undigested and reaches the colon, where it serves as food for beneficial gut bacteria. During fermentation, it produces short-chain fatty acids (SCFAs)—especially butyrate, which supports colon health.
Types of Resistant Starch
Resistant starch is categorized into five main types based on its source and how it resists digestion:
RS1 – Physically Inaccessible Starch:
Found in partially milled grains, seeds, and legumes.
Resistance due to physical barriers preventing enzyme access.
RS2 – Naturally Resistant Starch:
Found in raw potatoes, green bananas, and some high-amylose maize.
Resistance due to the starch’s crystalline structure.
RS3 – Retrograded Starch:
Formed when cooked starchy foods (like rice or potatoes) are cooled.
Cooling causes the starch to re-crystallize, making it resistant to digestion.
RS4 – Chemically Modified Starch:
Produced through chemical processes (e.g., esterification or cross-linking).
Commonly used in processed foods for texture and health benefits.
RS5 – Amylose-Lipid Complexes:
Formed when amylose interacts with fatty acids.
Found in foods cooked with fats or oils.