Development of clean-label protein- and fiber-enriched dry pretzels using hemp seed by-products

Abstract

This research investigates the incorporation of hemp seed cake (HSC), a nutrient-rich by-product of hemp oil extraction, into traditional pretzel formulations as a sustainable approach to functional dry pretzels development. Wheat flour was substituted with 5–40% HSC, and the resulting products were examined for proximate composition, bioactive profile, and sensory perception. Substitution with hemp seed cake significantly enhanced nutritional quality, raising protein from 7.49 to 12.62% and fiber from 0.90 to 11.78%, while lowering carbohydrates; notably, formulations containing ≥30% HSC meet EU Regulation 1924/2006 criteria to be labeled as a “source of protein.” Functional enrichment was further demonstrated by a four-fold increase in polyphenols (115.28–467.45 mg GAE/kg) and a corresponding rise in total flavonoids (63.40–262.28 mg GAE/kg), as well as by enhanced antioxidant capacity evaluated through DPPH (194.42–658.89 mg Trolox/kg) and ABTS assays (486.05–1647.23 mg Trolox/kg). Sensory analysis (CATA, PCoA) indicated that low substitution levels (≤10%) preserved traditional acceptability, whereas higher levels (≥30%) introduced nutty aroma and denser texture, perceived by consumers as novel. These findings highlight hemp seed cake as a multifunctional ingredient that improves nutritional density, enhances bioactive potential, and supports circular economy principles in the bakery sector.