The application of high-pressure processing to improve pumpkin flour's characteristics and utilization in gluten-free bread

This study evaluated the effect of high-pressure processing (HPP; 100, 300, and 600 MPa) on fresh pumpkin (Curcubita moschata) used to produce pumpkin flour (PF), and the impact of PF supplementation (2.5% and 5%) on gluten-free bread's quality. The physicochemical, techno-functional, antioxidant properties of the bread were analyzed over 3 days of storage. PF treated at 300 and 600 MPa had more particles < 300 µm, moisture, water activity, and starch–pectin than raw pumpkin (UNTR) and that treated at 100 MPa. The water absorbtion index was highest at 300 MPa, whereas UNTR and PF treated at 100 MPa had a higher water solubility index. All Commission Internationale de l'Eclairage (CIE) color parameters of PF were significantly affected by HPP. The apparent viscosity of PF increased at 300 and 600 MPa because of changes in starch and pectin. A higher specific volume was seen in in UNTR and 100 MPatreated PF breads at 5% PF than in breads with 600 MPa-treated PF and 2.5% PF. Color intensity was lowest at 600 MPa and decreased further after 3 days. Bread hardness was higher under the 600 MPa treatment at both Day 0 and Day 3. Pore frequency was highest in 600 MPa PF bread at 10 mm2 and lowest at 0.2 mm2. At 5% PF, total antioxidant capacity was lowest under the 300 MPa treatment, with no differences at 2.5% PF. Overall, the inclustion of 5% PF pretreated at 100 or 300 MPa provided a satisfactory balance of technological quality in bread.