Valorisation of grape seed powder in Turkish noodle erişte: effects on phenolics, texture, and cooking performance

Erişte, a traditional Turkish noodle, is a fundamental food product derived from cereal and can be nutritionally enriched. This study utilised grape seed powder (GSP), a by-product of winemaking abundant in polyphenols and fibre, to substitute wheat flour at levels of 0% (control), 2.5%, 5%, 7.5%, and 10% (w/w of flour) for the manufacture of functional noodles. The total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH radical-scavenging), color values (L*, a*, and b*), texture profile, and physicochemical and cooking properties of the noodles were assessed, and mathematical modelling was employed to characterise the level-response behaviour. Increasing the GSP level enhanced the TPC from 1755.49 to 4485.82 mg GAE/kg and the TFC from 93.40 to 384.10 mg CE/kg, representing approximately a 2.55-fold and 4.1-fold increase, respectively. The DPPH radical-scavenging activity was unaffected by the formulations (p>0.05). The incorporation of GSP produced noodles that were darker, redder, and less yellow (reduced L* and b* values, increased a* value), exhibiting more hardness, gumminess, and chewiness, but being less cohesive and springy. The water-holding capacity and swelling augmented, whereas water absorption and moisture content diminished. The cooking loss remained at an acceptable level (~6%) regardless of the GSP level. In conclusion, GSP can be considered a promising ingredient for producing phenolic- and flavonoid-enriched erişte while maintaining cooking stability.