Nutritional evaluation of carbohydrates in the Spanish diet: Non-starch polysaccharides and in vitro starch digestibility of breads and breakfast products

Abstract

Non-starch polysaccharides (NSP) and the in vitro starch digestibility of breads and breakfast products typically consumed in Spain were studied. Total (TS), rapidly digestible (RDS), slowly digestible (SDS) and resistant (RS) starch fractions were determined, as well as starch digestion rate indexes (SDRI) and rapidly available glucose (RAG) values as indicatives of the amount of glucose likely to be liberated into the blood stream. Total NSP contents were relatively low, varying from 8.7% to 6.3% in some breakfast cereals and wholemeal breads, respectively, to only 0.5% in other breakfast products. Insoluble hemicelluloses were the main NSP. Starch was rapidly digestible, resulting in SDRI over 90% in most cases. In general, RAG values were high, mainly in some breakfast products due to the presence of high amounts of free glucose. Typical Spanish breakfast products and breads are thus characterised by their potentially high glycaemic and insulinemic responses.