Inthalaeng Natthamon, Barker Ryan E, Dugmore Tom I J, Matharu Avtar S
Green Chemistry Centre of Excellence, Department of Chemistry, University of York, York YO10 5DD, UK.
Molecules. 2024 Nov 29;29(23):5665. doi: 10.3390/molecules29235665.
Blackcurrant pomace (BCP) is an example of an annual, high-volume, under-utilized renewable resource with potential to generate chemicals, materials and bioenergy within the context of a zero-waste biorefinery. Herein, the microwave-assisted isolation, characterization and potential application of defibrillated lignocelluloses from depectinated blackcurrant pomace are reported. Depectination was achieved using citric acid (0.2-0.8 M, 80 °C, 2 h, conventional heating) and compared with acid-free hydrothermal microwave-assisted processing (1500 W, 100-160 °C, 30 min). The resultant depectinated residues were subjected to microwave-assisted hydrothermal defibrillation to afford two classes of materials: namely, (i) hydrothermal acid-free microwave-assisted (1500 W, 160 °C, 30 min; DFC-M1-M4), and (ii) hydrothermal citric acid microwave-assisted (1500 W, 160 °C, 30 min; DFC-C1-C4). Thermogravimetric analysis (TGA) revealed that the thermal stability with respect to native BCP (T = 330 °C) was higher for DFC-M1-M4 (T = 345-348 °C) and lower for DFC-C1-C4 (322-325 °C). Both classes of material showed good propensity to hold water but failed to form stable hydrogels (5-7.5 wt% in water) unless they underwent bleaching which removed residual lignin and hemicellulosic matter, as evidenced by C solid-state NMR spectroscopy. The hydrogels made from bleached DFC-C1-C4 (7.5 wt%) and bleached DFC-M1-M4 (5 wt%) exhibited rheological viscoelastic, shear thinning, and time-dependent behaviour, which highlights the potential opportunity afforded by microwave-assisted defibrillation of BCP for food applications.
黑加仑果渣（BCP）是一种年产量高但未得到充分利用的可再生资源，在零废物生物精炼的背景下，具有生产化学品、材料和生物能源的潜力。本文报道了从脱果胶黑加仑果渣中微波辅助分离、表征和潜在应用的去纤化木质纤维素。使用柠檬酸（0.2 - 0.8 M，80 °C，2 h，常规加热）进行脱果胶，并与无酸水热微波辅助处理（1500 W，100 - 160 °C，30 min）进行比较。将所得的脱果胶残渣进行微波辅助水热去纤化，得到两类材料：即（i）水热无酸微波辅助（1500 W，160 °C，30 min；DFC - M1 - M4），和（ii）水热柠檬酸微波辅助（1500 W，160 °C，30 min；DFC - C1 - C4）。热重分析（TGA）表明，相对于天然BCP（T = 330 °C），DFC - M1 - M4的热稳定性更高（T = 345 - 348 °C），而DFC - C1 - C4的热稳定性较低（322 - 325 °C）。这两类材料都表现出良好的持水倾向，但除非经过漂白以去除残留的木质素和半纤维素物质（如通过碳固态核磁共振光谱所证明），否则无法形成稳定的水凝胶（在水中为5 - 7.5 wt%）。由漂白后的DFC - C1 - C（7.5 wt%）和漂白后的DFC - M1 - M4（5 wt%）制成的水凝胶表现出流变粘弹性、剪切变稀和时间依赖性行为，这突出了微波辅助BCP去纤化在食品应用方面提供的潜在机会。
