Resistant Starch

The early definitions for dietary fiber did not consider resistant starch as its presence was not yet recognized ( Table 3). Only the definitions proposed by LSRO (1987) and COMA (1998) specifically exclude resistant starch. The 1998 COMA definition is based on the Englyst method of analysis, which removes all starch from the fiber residue by solubilization with dimethyl sulfoxide. Some definitions, such as those of Germany and AACC, include resistant starch by specifically listing it; for others, such as those used in Belgium, Italy, and China, the wording of the definition indicates that resistant starch is part of fiber. Most other definitions, including the definition from the U.K. Food Standards Agency (Hignett, 2000), incorporate variable amounts of resistant starch as dietary fiber because they are based on AOAC procedures that do not analyze a portion of starch during fiber analysis (AOAC 991.43 and 997.08).

Depending on one's chosen diet, naturally occurring and manufactured resistant starch, as well as that produced during normal processing of foods for human consumption, could make a significant contribution to daily fiber intake. Legumes are the single largest source of naturally occurring resistant starch (Marlett and Longacre, 1996). In addition, green bananas (Englyst and Cummings, 1986) and cooled, cooked potatoes (Englyst and Cummings, 1987) can provide a significant amount of resistant starch. Resistant starch resulting from normal processing of a foodstuff is a more modest contributor to a typical daily intake. Starches specifically manufactured to be resistant to endogenous human digestion are a rapidly growing segment of commercially available resistant starches. Physiological effects and analysis of resistant starch are being intensively studied (Asp, 1997). Several issues remain to be addressed in these re