Spaghetti from durum wheat: effect of drying conditions on heat damage, ultrastructure and in vitro digestibility

The effects of low (LT) or high (HT) temperature drying on ultrastructural, molecular and in vitro digestibility properties of cooked spaghetti were studied. Starch swelling and denaturation/aggregation of proteins occurring at diverse stages, LT or HT drying and cooking, resulted in different in vitro digestibility of spaghetti. For the first time, these differences were assessed in terms of the release of free AA and simple sugars. Indeed, at the end of in vitro digestion, the total amount of released maltotriose, maltose and glucose significantly differentiated digestates of LT and HT spaghetti (12.6 and 15.9 g 100g⁻¹). In the same samples, diverse amounts (16.3 and 12.5 g 100g⁻¹ protein) of free amino acids were found. Chemical artifacts occurring at protein level impaired release of lysine in cooked HT spaghetti after in vitro digestion. These results increase the knowledge on digestibility of LT and HT cooked spaghetti.