Prolonged Proofing Modulates the Acrylamide Content, Nutritional and Functional Characteristics of Pumpkin (Cucurbita maxima Plomo) and Soft Wheat Composite Bread.

Abstract

Acrylamide formation in bread products poses health concerns, necessitating strategies to reduce its presence while maintaining nutritional value. This study investigated how different concentrations of pumpkin flour (Cucurbita maxima Plomo) and prolonged proofing times affect acrylamide content and bread characteristics. Composite bread samples were prepared with varying pumpkin flour shares (0-20%) to soft wheat flour using two proofing times (60 and 120 min). The study analyzed quality features, crust and crumb color, antioxidant activity, total polyphenolic content, reducing sugars, and acrylamide content of the resulting breads. Extended proofing (120 min) reduced acrylamide levels in the crust from 220 to 150 units in 20% pumpkin flour bread compared to 60 min proofing. Control bread showed the highest specific volume (2.40 ± 0.01 cm³/g) after 2 h of proofing, while 20% pumpkin flour addition decreased it to 1.69 ± 0.02 cm³/g. Initial hardness increased from 6.8 ± 1.5 N in the control to 14.3 ± 1.5 N in 20% pumpkin flour bread after 1-h of proofing. Water activity decreased from 0.966 ± 0.002 in the control to 0.945 ± 0.004 in 20% pumpkin flour samples with 2 h proofing. Optimal results were achieved with 5-10% pumpkin flour substitution combined with two-hour proofing, balancing improved nutritional properties and reduced acrylamide formation while maintaining acceptable bread quality parameters.