Almond by-products: Extraction and characterization of phenolic compounds and evaluation of their potential use in composite dough with wheat flour

Blanched skins and blanching water, by-products of almond processing, were evaluated as potential ingredients of bakery products. The research included three phases: i) optimization of skin drying; ii) optimization of qualiquantitative determination of phenolic compounds, by comparing three extracting protocols; iii) assessment of the impact of by-products on the rheology of composite doughs with wheat flour. The least time-consuming drying mode (at 60 degrees C for 30 min) retained better odor notes, higher content of phenolics (814 mu g/g d.m. by HPLC, with the most effective extracting method) and greater antioxidant activity than sun-drying. Blanching water showed 917 mu g/mL phenolics. Dried almond skins altered alveograph and farinograph indices of dough at doses higher than 30 and 50 g/kg, respectively, whereas blanching water did not cause significant changes. Therefore, almond skins could be used in products tolerating weak gluten network, such as cookies, whereas blanching water could be added to any bakery good.