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Abstract(s)
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.
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Pedagogical Context
Citation
Cardoso, Rossana V.C.; Fernandes, Ângela; González-Paramás, Ana M.; Barros, Lillian; Ferreira, Isabel C.F.R. (2018). Physicochemical characterization ofwheat and rye flours. In XXIV Encontro Luso Galego de Química. Porto. ISBN 978-989-8124-24-1