Rheological, pasting, and textural characteristics of wheat-sacha inchi (Plukenetia volubilis) composite flour and dough

Aim: This study aimed to evaluate the functional role of sacha inchi (Plukenetia volubilis) flour in wheat-based composite dough systems and to determine optimal substitution levels that balance between improved proximate nutritional composition and acceptable processing and dough performance. Methods: Six composite flour formulations (control—F5) were prepared by replacing wheat flour with sacha inchi flour at 5% intervals (0–25%). The flours and corresponding doughs were characterised for proximate composition, colour parameters, pasting properties and thermo-mechanical behaviour. Results: Proximate analysis showed progressive increases in crude protein (8.60% to 14.20%), crude fat (1.20% to 16.0%), crude fibre (0.20% to 0.38%), and ash (0.41% to 0.83%), alongside reductions in moisture (14.00% to 9.40%) and carbohydrate content (56.00% to 35.40%) with increasing substitution, while colour analysis showed reduced lightness (93.20 to 87.90) and increased redness and yellowness. RVA analysis revealed significant decreases in peak viscosity (3,700 to 1,670 cP) and setback viscosity (1,600 to 1,000 cP). Mixolab measurements showed decreased water absorption, reduced protein stability (C2 decreased from 0.59 to 0.27 Nm), and modified starch gelatinisation behaviour, with C3 peaking at lower substitution levels. Texture profile analysis indicated increased dough hardness (1,070 g to 2,300 g) and decreased cohesiveness (0.78 to 0.23) and springiness (0.53 to 0.13) at higher substitution levels. Conclusions: These findings demonstrate that sacha inchi flour functions as both a nutritional enhancer and a structural modifier in wheat-based systems. Substitution levels up to 15% are recommended to achieve an optimal balance between improved nutritional value and acceptable processing and dough performance, supporting its application in functional bakery formulations.