Resistant starch content in a selection of starchy foods on the Swedish market

Objective: The objective was to determine the resistant starch (RS) content in a selection of typical starchy foods on the Swedish market. In addition, the daily RS intake was estimated from Swedish food consumption data. Design: The major forms of RS, including physically encapsulated starch, were determined with an in vitro method using chewing as a pre-step before enzymatic incubation. Setting: The study was performed at the Department of Applied Nutrition and Food Chemistry, Lund University, Sweden. Subjects: Six healthy subjects were used to chew the food products before enzymatic incubation of the samples. Results: Twenty-five cereal, potato and legume products were included in the study. The highest IRS concentration was noted in the legume group (9.5 -11.1 % total starch basis). Commercially processed potato products were found to have a higher IRS content (4.8-5.9%), compared with boiled potatoes (2.0%). Among the cereal products, bread with enclosure of intact rye grains, barley flakes and semolina porridge, respectively, were identified to have a IRS level in the higher range (4.5 - 6.0%). The daily RS intake was estimated to be 3.2 g. Conclusions: The main RS sources in the Swedish diet are bread and potato products, which contribute approximately 1.3 and 1.2 g RS per day, respectively. Based on food habits the RS intake may vary considerably, thus when added to dietary fibre intake, the contribution of IRS may be of nutritional importance for certain individuals.