In this study, the subcritical butane extraction process of fenugreek seed oil was optimized using response surface methodology with a Box-Behnken design. The optimum conditions for extracted oil from fenugreek seed was as follows: extraction temperature of 43.24 °C, extraction time of 32.80 min, and particle size of 0.26 mm. No significant differences were found between the experimental and predicted values. The physical and chemical properties of the oil showed that the oil could be used as edible oil. Fatty acid composition of oils obtained by subcritical butane under the optimum conditions and by accelerated solvent extraction showed negligible difference. The oils were rich in linoleic acid (42.71%–42.80%), linolenic acid (26.03%–26.15%), and oleic acid (14.24%–14.40%). The results revealed that the proposed method was feasible, and this essay shows the way to exploit fenugreek seeds by subcritical butane extraction under the scope of edible oils.

Lignocellulosic biomass, such as corn bran, has limited accessibility to solvents during thermal-chemical processes. However, a pretreatment can help to change the characteristics of the raw material and improve the yield of the polysaccharides. A twin-screw extrusion pretreatment was developed to enhance the polysaccharide yield and decrease the optimum temperature and time during the hydrothermal treatment of corn bran. The effects of temperature and time on the polysaccharide yield were investigated during the hydrothermal treatment with pretreated and unpretreated corn bran. All samples were comparatively analyzed by Xray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis to investigate the changes in the chemical and physical characteristics. The results showed that the twin-screw extrusion pretreatment changed the main physical structure and thermochemical behavior of corn bran, which confirmed that it could enhance the polysaccharide yield and decrease the optimum treatment temperature and reduce the process duration. The pretreatment and the hydrothermal treatment temperature also had a synergetic effect on extraction yield and the composition of polysaccharide fractions of corn bran compared to the unpretreated sample. This study contributes to the knowledge improvement of corn bran pretreatments, which can be used for the efficient production of polysaccharides.

This study investigated the effects of various solvents on cypress liquefaction in the range of 180 to 300 °C. The solid residues and bio-oils obtained from cypress liquefaction were characterized to investigate the mechanism of the liquefaction process. Results obtained using FT-IR, sugar analysis, and elemental analysis showed that the solvent could affect both the formation of various compounds in the bio-oil and the product distribution during the cypress liquefaction process. Considering the bio-oil yield, the solvent efficiency in cypress liquefaction was as follows: water > methanol > ethanol. The decomposition velocities of cellulose, hemicelluloses, and lignin were different in the solvents, and hemicellulose decomposition preceded cellulose and lignin in all solvents. Water had the most pronounced effect on the higher heating value (HHV) of residues among the three tested solvents; the highest HHV was 26.3 MJ/Kg. This study suggests that characterization of products provides a promising approach for investigating the mechanism of solvent effects on biomass liquefaction.

The objective of this investigation was to elucidate the structural changes of the polysaccharides isolated by hydrothermal treatment of corn bran after twin-screw extrusion. The structures and antioxidant activities of the purified polysaccharides were investigated and compared by monosaccharide analysis, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR). The results showed that the structures of the linkages and monosaccharide components of the purified polysaccharides were not affected strongly by the twin-screw extrusion pretreatment. However, the purified polysaccharides isolated from pretreated samples displayed significant differences in monosaccharide ratios, degree of branching/ linearity, and molecular weight. These physical changes may be related to the decrease of antioxidant activities of the polysaccharides. The present investigation contributes to the knowledge of how pretreatment by twin-screw extrusion affects the chemistry of corn bran polysaccharides. Results can be applied to improve the efficiency of hydrothermal extraction of polysaccharides from corn bran.