Search

1. Root lignin is a key driver of root decomposition, which in turn is a fundamental component of the terrestrial carbon cycle and increasingly in the focus of ecologists and global climate change research. However, measuring lignin content is labor-intensive and therefore not well-suited to handle the large sample sizes of most ecological studies. To overcome this bottleneck, we explored the applicability of high-throughput near infrared spectroscopy (NIRS) measurements to predict fine root lignin content. 2. We measured fine root lignin content in 73 plots of a field biodiversity experiment containing a pool of 60 grassland species using the Acetylbromid (AcBr) method. To predict lignin content, we established NIRS calibration and prediction models based on partial least square regression (PLSR) resulting in moderate prediction accuracies (RPD = 1.96, R 2  = 0.74, RMSE = 3.79). 3. In a second step, we combined PLSR with spectral variable selection. This considerably improved model performance (RPD = 2.67, R 2  = 0.86, RMSE = 2.78) and enabled us to identify chemically meaningful wavelength regions for lignin prediction. 4. We identified 38 case studies in a literature survey and quantified median model performance parameters from these studies as a benchmark for our results. Our results show that the combination Acetylbromid extracted lignin and NIR spectroscopy is well suited for the rapid analysis of root lignin contents in herbaceous plant species even if the amount of sample is limited.

Background: In this study, soy protein isolate/sugar beet pectin (SPI/SBP) emulsion gels were prepared through an enzymatic gelation process. The effects of emulsifier (SBP, SPI or SPI/SBP complex) and emulsification process on the microstructure, texture, breakdown properties and aroma release behavior of resulting emulsion gels were investigated., Results: Oil emulsification by SBP/SPI complex resulted in a higher amount of emulsifier absorbing on the oil-water interface than by SBP and SPI alone, indicating that a more compact interfacial network was formed. Flocculation of oil droplets was observed and corresponding emulsion gels exhibited lower fracture force and strain when the oil was emulsified by SPI and SBP/SPI complex. Moreover, emulsion gels with small droplets produced a greater quantity of small fragments after mastication. However, microstructure did not have a significant effect on breakdown properties of emulsion gels. Headspace gas chromatography analysis showed that the release rate of ethyl butyrate before and after mastication was significantly lower in emulsion gel with more compact network, but the release of aroma compounds with higher hydrophobicity did not show a significant influence of the microstructure and texture of emulsion gel., Conclusion: This finding provides a useful application for designing semi-solid foods with desirable flavor perception. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)