105(3)_str33

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 105, No. 3 (2018), p. 257–264
DOI  10.13080/z-a.2018.105.033

Thermophysical and chemical properties of seeds of traditional and double low cultivars of white mustard

Ewa ROPELEWSKA, Krzysztof J. JANKOWSKI, Piotr ZAPOTOCZNY, Bożena BOGUCKA

Abstract

The aim of this study was to compare the thermal, physical, mechanical and chemical properties of white mustard (Sinapis alba L.) seeds of the traditional cultivar ‘Radena’ and the double low cultivar ‘Warta’. The selected thermal properties were determined with an analyser KD2 Pro. Cultivar ‘Warta’ was characterised by higher thermal conductivity (0.126 W m-1 K-1), volumetric heat capacity (1.448 MJ m-3 K-1) and specific heat capacity (1.987 kJ kg-1 K-1) and lower thermal resistivity (793.3°C cm W-1) than ‘Radena’ (thermal conductivity 0.122 W m-1 K-1, volumetric heat capacity 1.398 MJ m-3 K-1, specific heat capacity 1.850 kJ kg-1 K-1, thermal resistivity 820.5°C cm W-1). Cultivars ‘Warta’ and ‘Radena’ had identical thermal diffusivity (0.087 mm2 s-1). The values of the highest initial endothermic peaks and the last endothermic peak were determined from differential scanning calorimetry curves. The mean values of common peaks for both cultivars were determined at −17.5, 86.0 and 402.3 °C for ‘Warta’, and −16.5, 69.9 and 400.1 °C for ‘Radena’. In ‘Radena’, an additional peak appeared at a temperature of 0.8°C. The area under the differential scanning calorimetry curve was 1539 J g-1 for ‘Warta’ and 1847 J g-1 for ‘Radena’. The cultivar ‘Warta’ was characterised by lower bulk density and true density, higher porosity and larger dimensions than the cultivar ‘Radena’. The bulk density of mustard seeds was equal to 0.729 g cm-3 for ‘Warta’ and 0.755 g cm-3 for ‘Radena’, true density 1.169 g cm-3 (‘Warta’) and 1.203 g cm-3 (‘Radena’), porosity 37.73% (‘Warta’) and 37.18% (‘Radena’), length 2.55 mm (‘Warta’) and 2.49 mm (‘Radena’), width 2.29 mm (‘Warta’) and 2.27 mm (‘Radena’). The seeds of cultivar ‘Radena’ had higher hardness (24.7 N), higher crude protein content (341.9 g kg-1 dry matter, DM) and lower crude fat content (182.9 g kg-1 DM) than the seeds of ‘Warta’ (21.6 N, 315.5 g kg-1 DM and 243.3 g kg-1 DM, respectively).

Key words: chemical properties, differential scanning calorimetry, physical properties, ‘Radena’ (traditional cultivar), thermal properties, thermogravimetric analysis, Sinapis alba, ‘Warta’ (double low cultivar).

Full text: 105_3_str33.pdf