2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Resistant starch (RS) is the portion of starch that is not digested in the human small intestine. Because humans differ in their ability to digest a particular RS-containing material, there is no absolute distinction between the RS and the non-RS in a particular RS-containing sample. Nevertheless, RS is commonly determined using in vitro procedures as if RS were a well-defined chemical entity. A portion of the RS can appear by analysis as total dietary fiber (TDF). Moreover, some researchers have used the TDF method to determine RS levels or to isolate RS per se. In vitro RS determination by different methods can lead to confusion when comparing the RS levels in different RS-containing materials. Moreover, the nature of a particular RS-containing ingredient may change as a result of treatments in processing or manufacturing. The differing nature of the enzyme-resistant material in types 1, 2, 3, and 4 RS will be discussed. Emphasis will be on high-amylose maize starch-based materials containing types 2 and/or 3 RS, and the effect of subsequent treatments on the RS in these materials.