HİDROJEL ENKAPSÜLLÜ KIRMIZI ASMA YAPRAĞI FENOLİKLERİYLE GLUTENSİZ KEKLERİN GELİŞTİRİLMESİ: İLERİ GLİKASYON SON ÜRÜNLERİ ÖNCÜLLERİ VE KALİTE ÖZELLİKLERİ ÜZERİNE ETKİLERİ

The study investigated the potential of encapsulating phenolic compounds from red vine leaves (V􏰃t􏰃s v􏰃n􏰃fera L.) in hydrogel and adding them to gluten-free muffin formulations to improve the functional and quality characteristics of the products, as well as their effect on the levels of glyoxal (GO) and methylglyoxal (MGO), which are precursors of advanced glycation end products (AGEs). Phenolic compounds were obtained from leaves of Royal (RY), Black Kismis (KS), and Spil Karası (SK) varieties and encapsulated using hydrogels prepared with flaxseed gum (FG). Muffins enriched with phenolic compounds were compared with muffins produced using water-based control (WT), xanthan gum (XG), and flaxseed gum (FG) hydrogels. The study evaluated the effects on the rheological properties of muffin batters and the physicochemical, textural, and sensory properties of the baked product. The consistency coefficient (K) of muffin batters containing hydrogel increased, and all batters exhibited shear thinning behavior (n < 1). All batter samples exhibited viscoelastic solid properties defined by G' > G" values. The addition of hydrogel caused an increase in the storage (G') and loss modulus (G") values of the batters, which revealed a general improvement in the viscoelastic behavior of the batters. The addition of encapsulated phenolics provided a protective effect against oxidative deterioration by increasing the phenolic content and antioxidant capacity in the muffins. The addition of XG and FG limited the increase in hardness during muffin storage, while a significant increase in hardness occurred in WT and phenolic-added samples. At the end of storage, XG muffins maintained the highest cohesiveness and resilience values, while the presence of phenolic compounds caused a decrease in these parameters. In phenolic-added samples, a decrease in GO and MGO levels was observed compared to FG samples. Sensory analysis results showed that the addition of XG and FG positively affected the overall quality of the muffins. Muffins with XG addition scored the highest in appearance and texture, and were found to be significantly better than other samples (p<0.05). In contrast, muffins with RY, KS, and SP additions, which had high phenolic compound content, showed a decrease in flavor and sweetness scores due to bitter taste, which had a negative effect on overall acceptance. Nevertheless, muffins with XG and FG additions were found to have high overall sensory acceptability. The study demonstrated that hydrogel encapsulation is effective in preserving the stability and functional properties of phenolic compounds; however, the most suitable formulation to maintain sensory quality must be determined.