Starch digestibility and properties of fresh pasta made with semolina-based liquid sourdough

The aim of this work was to develop an innovative formulation of fresh pasta, which combined semolina and liquid sourdough. Quality and shelf-life of pasta were monitored on unpacked fresh pasta and on pasta packed in modified atmosphere after pasteurization. The addition of sourdough and the pasteurization were responsible for a yellowness increase of pasta. After in vitro digestion of cooked pasta, a lower proportion of slowly digestible starch (SDS; 43.0 g/100 g) and a higher proportion of inaccessible digestible starch (IDS; 40.2 g/100 g) was found in sourdough pasta than the control (49.8 and 34.5 g/100 g of SDS and IDS), and in pasteurized pasta (44.0 and 39.3 g/100 g of SDS and IDS) than the fresh pasta (48.8 and 35.4 g/100 g of SDS and IDS). FT-Raman spectra of pasteurized sourdough pasta showed a higher level of retrograded starch, as indicated by the lower value (479.14 cm−1) of the frequency of the band peaked at ∼480 cm−1, than the pasteurized control (479.47 cm−1). Unpacked sourdough pasta could be stored for one week without mould growth, which on the contrary appeared in the control. The pasteurization was more effective in sourdough pasta, with the complete disappearance of the microorganisms.