Effect of Hazelnut Skin Addition on Quality Characteristics of Functional Crackers

Hazelnut skin, an innovative by-product, has been classified as one of the richest sources of edible phenolic compounds in recent studies. In this study, hazelnut skin powder was used in cracker formulation at 5, 10, 15 and 20% ratios replaced with wheat flour, and some technological, chemical properties and bioactive components of cracker samples were determined. The hazelnut skin powder used as raw material has 5.1, 4.8, 3.9, 11.6, 1244 and 20 times higher ash, phytic acid, total phenolic content, DPPH, FRAP, CUPPRAC values than wheat flour, respectively. Increasing hazelnut skin powder in cracker production increased the darkness and redness of the cracker. High hazelnut skin powder usage ratios improved the spread ratio and reduced the hardness of the crackers. Increasing use of hazelnut skin powder in cracker increased the amount of ash, fat, phytic acid and resistant starch from 1.59%, 13.63%, 246.58 mg/100g and 0.97% up to 2.13%, 16.53%, 581.54 mg/100g and 2.15%, respectively. Antioxidant (DPPH, FRAP and CUPRAC) and phenolic substances (free, bound and total) increased significantly (p<0.05) at all hazelnut skin powder usage ratios. The high utilization ratios (15-20%) of hazelnut skin powder negatively affected overall acceptability of the crackers.