Potato-based fresh pasta (gnocchi): influence of formulation on dough quality characteristics

Introduction: Potato puree made from fresh tubers, soft wheat flour, pasteurized liquid eggs and salt are the ingredients used in the formulation of doughs to industrially produce a typical Italian potato-based fresh pasta (gnocchi). In this study the effect of ingredients on quality characteristics of gnocchi doughs was investigated. The aims of this research were: (i) to evaluate the physicochemical and textural properties of different gnocchi doughs, in the way that all the combinations of ingredients allowed to produce samples to be extruded in the final product; (ii) to study the relationship between dynamic (fundamental) and static (empirical) rheological measurements and therefore to assess the connection between the viscoelastic and textural characteristics of differently formulated gnocchi doughs. Methodology: 27 different samples, including 3 replicates of the control dough, were analysed in terms of dry matter content, colour (L*, h° and C*), static (firmness, consistency, cohesiveness and index of viscosity) and dynamic (G’, G’’ and *) rheological properties, residual starch content and freezable water. Results and Discussion: The overall results indicated that the different amounts of the ingredients produced gnocchi doughs with statistically significant differences in the dry matter content, colorimetric parameters (h° and C*) and residual starch content (R2 adj. = 0.88; R2 adj. = 0.60; R2 adj. = 0.73 and R2 adj. = 0.95, respectively). In particular, soft wheat flour was the ingredient that had an high and positive effect on the dry matter and on the residual starch contents of gnocchi doughs. The different gnocchi doughs were not significantly different in terms of both static and dynamic rheological properties. Conclusions: Among the ingredients involved in the formulation, soft wheat flour seemed to be the most crucial one in affecting the quality features of gnocchi doughs. Significant relationships between dynamic (rheometry) and static (textural analysis) methods were also found out.