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Evaluation of the effect of zwitterionic buffers on termite gut protists
2018 - IRG/WP 18-10933
The thermal modification of wood is recognized as the most commercialized wood modification process. The treatment of wood at temperatures usually greater than 180 ºC results in a product with some properties enhanced (dimensional stability, durability, aesthetical colour) and some diminished (mechanical properties). The loss of mechanical strength is recognized as a limitation to the use of thermally modified wood in certain products. The mechanical strength reduction is linked in varying degrees to the release of acidic volatile species, the acid-catalysed depolymerisation of the hemicelluloses present and the plasticization and redistribution of the lignin components present. Buffers, although been designed not to influence the reaction systems, may have some interactions when exposed to some conditions, potentially acting as promoters of biological changes on different systems. In this study, two zwitterionic buffers, bicine and tricine, were chosen to be tested regarding their volatilization reduction properties, as well as tricine due to offering the potential of forming Maillard-type products with fragmented hemicelluloses/volatiles. In order to determine if there were any resultant effects of the bicine and tricine treatments submitted or not to thermal modification, the efficacy against subterranean termites was conducted as well as an evaluation of the effect of the different combinations of treatments on the termite gut symbiotic protists. The durability of thermal modified wood is recognized as low and the results of the present work are in accordance with that perception. However, bicine and tricine treatments alone had a clear influence on the survival of the termites and the study of the protist symbionts (9 morphotypes) gave a better insight of the ability of termites to react to unfavorable diet changes.
S Duarte, D Jones, L Nunes
The use of bicine and tricine as possible Maillard reagents in a combined thermal/chemical modification of beech
2019 - IRG/WP 19-40852
The effects of thermal modification have been well established, particularly in terms of reductions in mechanical performance. In recent years, there has been an increase in studies related to the Maillard reaction. More commonly associated with food chemistry, it involves the reaction of amines and reducing sugars during cooking procedures. This paper has attempted to combine the use of amines and thermal modification, with subsequent properties investigated for the treatment of beech (Fagus sylvatica). In this initial study, the combined effects of chemical treatments by tricine and bicine were investigated with thermal modification. Along with some preliminary data on mechanical properties, the modifications which appeared in the wood structure were evaluated by infrared spectroscopy. After the treatment about 6-7 % of WPG was identified in treated samples, but further thermal treatment decreased the WPG to about 5%. The modifications appearing in the spectra were mostly related to increase of the intensities of the bands assigned to C=O groups but also to N-H and C-N groups, with shifting of some bands to higher wavenumber values
D Jones, C-M Popescu, D Krzisnik, M Hocevar, M Humar, M-C Popescu