Physicochemical characterization ofwheat and rye flours

Rye (Secale cereale L.) and wheat (Tritícum aestivum L.) are widely grown cereais consumed as bread ali over the word [l]. Cereais are processed by crushing using different types of mills and the force applied for cereais grinding reduce the particle sizes resulting in several types offlours [2]. Thus, the chemical composition of cereal grains aíFects their functional and technological characteristics. The present work evaluated the quality ofwheat and rye flours according to the degree ofrefinement by determining the physicochemical parameters. Seven flours were kindly donated by the Milling Company "Moagem do Loreto", Bragança, Portugal, in December 2017, namely T 55 and T 65 (wheat flours - refined samples), T 150 (whole wheat flour), T 70 and T 85 (rye flours - refined samples), and T 130 and T 170 (whole rye flours). Macronutrients and energetic value were determined according to official procedures offood analysis, while gluten was obtained by the addition of2% NaCl solution and washed under stream ofrunning water, and pH was determined by a calibrated digital pH meter. The moisture content ranged from 9.3% to 14.7% in whole rye flour T 130 and whole wheat flour T 150, respectively. The protein content ranged between 6.93 g/100 g dw and 14.6 g/100 g dw in rye flour T 70 and in whole wheat flour T 150, respectively. lhe ash content in wheat flour presented lower values, namely T 55 (0.31 g/100 g dw) and T 65 (0.32 g/100 g dw). The fat content in wheat flours T 55 presented the lowest amount (0.76 g/100 g dw) while the rye flours T 170 presented the highest one (1.78 g/100 g dw). The difFerent types offlour (wheat and rye) contained coinparable amounts of total carbohydrates ranging between 82.4 to 91.3 g/100 g dw. The highest pH value was found in whole rye flour T 130 (6.44) and the lowest inwheat flour~T 65 (6. 04). Concerning dry and wet gluten, these were only detected in wheat flours. Dry and wet gluten ranged from 7.2% to 9.5% and 19.9% to 25. 0%, respectively. These results agree with the Portuguese legislation and with the information procedure in the field of technical standards and rules previewed by the European Parliament and Council. The physical chemical characterization of flours points to an important ingredient in the manufacture ofbakery and pastry products.The authors are grateful to Afonso, Lopes & Cia, Lda," Moagem do Loreto"for the donation of flour, and the Foundation for Science and Technofogy (FCT, Portugal) and FEDER under Programme PT2020 for financiai support to CIMO (UID/AGR/00690/2013), L. Barros contract and A. Fernandes post-doc grant (SFRH/BPD/114753/2016). This work is also funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural*.