Effects of Boiling and Steaming on the Carbohydrates of Sweet Corn

Sweet corn is an important source of carbohydrates in the human diet. In this study, the effects of the two most commonly used cooking methods (boiling and steaming) on the contents of individual sugars, sugar alcohols, oligosaccharides, total starch, resistant starch (RS), phytoglycogen, water-soluble carbohydrates (WSC), and dietary fibers (DF) were investigated using yellow and bicolor sweet corn samples. Four simple sugars, sucrose, glucose, fructose, and maltose, were identified. Boiling and steaming did not alter the concentrations of sucrose but resulted in the decrease of other three minor sugars. Sorbitol and mannitol were identified as the primary sugar alcohols. Sorbitol decreased in cooked samples, while mannitol remained unchanged regardless of the cooking method. Oligosaccharides and phytoglycogen were not detected in either variety. Boiling and steaming did not alter the content of WSC, total starch, or higher-molecular-weight DF but led to a significant reduction of RS and total DF. This study provided understanding on how cooking may affect the health benefits and quality of sweet corn.