CBOT corn. Starch futures outside the market, CBOT corn varieties rose, corn starch continued to decline. Externally, CBOT corn closed higher on Tuesday. Traders said that this is due to the spillover effect of soybean and wheat futures. Starch is a kind of high molecular carbohydrate, which is polymerized by glucose molecules. Its basic unit is α-D- glucopyranose, and its molecular formula is C6H 12O6.