RESEARCH ARTICLES Optimization of White Wheat Flour Dough Rheological Properties with Different Levels of Grape Peels Flour Addition Silvia MIRONEASA 1* , Mădălina IUGA 1 , Dumitru ZAHARIA 2 , Costel MIRONEASA 3 1 Faculty of Food Engineering, Stefan cel Mare University of Suceava, Romania 2 S.C. Dizing S.R.L. Brusturi, Neamţ, România 3 Faculty of Mechanical Engineering, Mechatronic and Management, Stefan cel Mare University of Suceava, Romania * corresponding author: silviam@fia.usv.ro; silvia_2007_miro@yahoo.com Bulletin UASVM Food Science and Technology 76(1)/2019 ISSN-L 2344-2344; Print ISSN 2344-2344; Electronic ISSN 2344-5300 DOI: 10.15835/buasvmcn-fst: 2018.0017 Abstract The use of grape peels flour to improve the nutritional value of wheat flour bread has received considerable interest due to their high fibers content and bioactive compounds compared to white wheat flour. The aim of this study was to establish the optimal combination of grape peels particle size (PS) and flour replacement (FR) level with grape peel flour on the dynamic and empirical rheological properties of mix flour dough to develop innovative bakery products. The results obtained highlighted that the small PS resulted in increased Farinograph water absorption and Amylograph peak viscosity and decreased dough development time. The FR showed a significant (p < 0.05) effect on Rheofermentometer parameters. The dynamic moduli increased when increasing FR and decreasing PS, while the loss tangent decreased with FR increase. The white wheat flour with 3.80% small particle size of GPF was found to be the best formulation in order to achieve the desirable dough rheological properties. Keywords: grape peels flour, optimization, particle size, rheology, white wheat flour Introduction The addition of dietary fiber from various sources in wheat-based bakery foods is a solution to the existing problem regarding the human nutrition and health. Dietary fiber intake (25-50 g per day) has been associated with prevention or treatment of some diseases such as, regulation of the intestinal tract, diabetes, several types of cancer, etc. (Kendall et al., 2010; Rodríguez et al., 2006). Due to the relationships between food and health, the development of functional foods like fiber enriched-bread is increasingly explored in various works. Bread, as a regular basis, represents an interesting vehicle for dietary fiber incorporation. Agro-industrial by-products derived from fruits and vegetables processing can become ingredients of value added products due to their nutrients and extranutritional compounds, with the associated health benefits (Gomez and Martinez, 2017). Dietary fibers from fruits have better quality than those from cereals (Figuerola et al., 2005). Grapes pomace, a by-product of wine industry, consists mainly of peels and seeds, represents approximately 20-25% of the weight of the grapes processed for wine production (Yu and Ahmedna, 2013). Grape peels and seeds are composed of water, proteins, lipids, carbohydrates, vitamins and minerals, being also a rich source of high- value compounds, such as phenolics antioxidants (flavonoids, phenolics acids and stilbenes) and dietary fiber (Nerantzis and Tataridis, 2006; Deng