Development of gluten-free premixes with an improved nutritional profile: effect of Jerusalem artichoke powder on the technological quality of millet–legume blends

Gluten-free (GF) foods are produced mainly from refined flours and starches, resulting in products with low nutritional value. The incorporation of legume flours and fiber-rich plant ingredients to improve the nutritional profile of GF products remains a technological challenge. This study evaluated the effect of incorporating a fructan-rich dried Jerusalem artichoke (Helianthus tuberosus L.) powder (JAP) on the techno-functional, pasting, and thermal properties of nutritionally enhanced GF premixes. Three formulations were prepared using 68% millet flour (M) as the base ingredient, 23% legume flour —pea (P), red lentil (R), or lupin (L)— and 9% JAP. The techno-functional properties of JAP and the individual flours were determined by measuring water absorption capacity (WAC), water holding capacity (WHC), oil absorption capacity (OHC), and swelling capacity (SC). Pasting properties were assessed using a Rapid Visco Analyzer, while thermal properties were evaluated by differential scanning calorimetry in millet–legume premixes with JAP (MPJAP, MRJAP, and MLJAP) and without JAP (MP, MR, and ML). Compared with the flours, JAP exhibited significantly higher WAC (6.8±0.5 g H₂O/g d.b), WHC (3.15±0.24 g H₂O/g d.b), and SC (7.5±0.2 mL/g d.b) values. The incorporation of JAP resulted in lower peak (915-1523 cP) and final viscosities (898-2110 cP), higher pasting temperatures (87.5-90 ºC), and lower setback values (320-1135 cP), suggesting a reduced tendency toward amylose retrogradation. In addition, JAP modified the thermal behavior of the blends by increasing gelatinization temperatures (64-88 ºC), reducing gelatinization enthalpy (0.7-7.4 J/g), and inhibiting starch retrogradation in all formulations. These findings suggest that JAP regulates water availability within the system, delaying starch gelatinization and limiting molecular reorganization. This effect is mainly attributed to fructans, although legume components may also contribute. Overall, JAP provides technological advantages for the development of gluten-free premixes with improved processing stability and the potential to produce higher-quality gluten-free products.