Aim of this work was to evaluate the effects of partial replacement of semolina with inulin on the technological, sensory and nutritional characteristics of spaghetti made from wheat flour. In particular, the tests were performed using two different types of inulin, with different polymerization degree. Results demonstrate that the use of the fiber at higher molecular weight causes minimal changes in the dough, up to 20% replacement level. Conversely, lower molecular weight inulin has negative effects on spaghetti tenacity, on solid loss by cooking and on product sensory acceptability, even at low replacement levels. Through microscopic analysis it was also noted that the starch granules are encapsulated by a protective inulin layer. This disfavors starch digestibility because such layer acts as a physical barrier against enzymes responsible for its degradation. However, in the case of samples containing high levels of inulin, the formation of a more open structure was noticed, which doesn’t interfere with the action of such enzymes. In conclusion, the authors affirm that using a typology of inulin with an even higher polymerization degree than the one used during testing, products are provided with better glycemic index, without significantly affecting the quality of the pasta.
N. Aravind et al., Food Chemistry, 132, 2012, 993-1002