Comparative Analysis of the Glycemic Index of Amaranth and Other Gluten-Free Products

Introduction. For patients with gluten intolerance, diet therapy is the main method of treatment. However, gluten-free diets are found lacking in many important components. Children that fail to consume neccessary nutrients or have problems with their absorption tend to be physically retarded. Gluten-free diet may increase the risk of autoimmune diseases, especially type I diabetes. Therefore, products for children with celiac diseases should be both gluten-free and have adequate bioavailability of carbohydrates. This article features the chemical composition of amaranth, the geometric structure of starch grains, and its effect on the formation of colloidal solutions. It also compares the glycemic index (GI) of amaranth with other gluten-free grains, i.e. rice, buckwheat, and corn. Study objects and methods. The research featured native amaranth grain (Amaranthus cruentus) (Mexico), puffed amaranth kernels (Mexico), and coarse granular amaranth flour (Mexico). Results and discussion. Amaranth grain contains 12.5–23% of protein, 50.7–77.0% of carbohydrates, 6.0–8.0% of lipids, 10.5–18.3% of dietary fiber, and 2.5–3.5% of minerals. The GI of amaranth and its products were compared with similar values of other glutenfree crops, namely rice, buckwheat, and corn. Amaranth grain and its products demonstrated a higher GI, if compared with other gluten-free grain raw materials. The GI of amaranth grain was 87, the GI of the puffed amaranth kernels was 101, and the GI of the coarse granular amaranth flour was 97. Amaranth starch is easy to digest, which is mainly due to the high content of amylopectin (88 to 98%), since amylopectin breaks down faster than amylose. The relatively small size of starch granules (1.5–3.0 microns) increases the attack capacity of enzymes. These properties make amaranth starch glycemic, or low-resistant, which means that amaranth is easily digested and possesses stability to retrogradation. Conclusion. The unique nutritional and functional properties of amaranth gluten-free products can significantly improve the diet of children with gluten intolerance. However, amaranth starch and its products have a high GI. Hence, it is necessary to control the percentage of these components in formulations and be careful with the selection of additional components and their impact on the total GI.