THE HIGH POLYMERIZATION DEGREE INFLUENCES THE INULIN BIOACCESSIBILITY IN DURUM WHEAT SPAGHETTI

Objective In order to evaluate how the polymerization degree (PD) could influence the permanence of inulin in small intestine, two inulins at high and low PD were used at 4% (w/w) concentration to enrich durum wheat spaghetti. They were characterized and inulin bioaccessibility assessed by an in vitro gastrointestinal digestion. Methods Two types of inulin: cardoon roots (CRI high PD) and chicory (CHI low PD) were used for the spaghetti production. The inulin analysis in cooked spaghetti was performed after acid hydrolysis (2 hr, 70°C) and soluble carbohydrates analyzed (Dionex HPLC-PAD). Digestion performed according to D'Antuono et al. 2016. Results Inulin content was similar (CRI, 8.1 and CHI, 8.2 mg/g FW) while after digestion its amount changed. In CRI spaghetti, bioaccessibility was lower (39%) than CHI spaghetti (99%), indicating that the drastic digestive condition hydrolyzed completely the inulin increasing the fructose release, while in CRI spaghetti the inulin was preserved in pasta. Conclusions These preliminary results show that the inulin bioaccessibility was influenced by its degree of polymerization, suggesting that the accumulation in pasta makes inulin directly available in the last intestinal tract as substrate for health promoting actions.