Pinus nigra Schneid) sapwood. A brown rot fungus [Coniophora puteana (Schum.:Fr)] was selected in order to determine and compare the effectiveness (threshold value) of the linear chain anhydrides.
The work described in this paper has demonstrated that chemically modified Corsican pine sapwood afforded substantial bioprotection
against Coniophora puteana. With all anhydrides studied, a weight gain of 18% following reaction ensured complete protection. The results indicate that
degree of cell wall bulking by the bonded adduct, rather than extent of hydroxyl substitution is the primary factor controlling
decay resistance.
Biologische Wirksamkeit der Holzmodifikation mit Fetts?ureanhydriden zum Schutz gegen Braunf?ule (Coniphora puteana)
P. nigra Schneid .). Geprüft wurden die Anhydride von Essig-, Propion-, Butter-, Valerian- und Caprons?ure. Als Testpilz diente der Braunf?ulepilz
Caniophora puteana (Schum. : Fr.). Die Ergebnisse zeigen eine erhebliche Verbesserung der biologische Resistenz gegen diesen Pilz nach der chemischen
Modifizierung des korsischen Kiefernholzes. Mit allen Anhydriden konnte mit einem Massenzusatz von 18% ein vollst?ndiger Schutz
erreicht werden. Die Ergebnisse deuten darauf hin, dass das Ausma? der Zellwandbelegung und nicht so sehr die Substitution
der Hydroxylgruppen der ausschlaggebende Faktor zum Schutz vor biologischem Abbau ist.
ANP would like to thank the State Scholarships Foundation of Greece for funds to conduct this research. 相似文献
Termite resistance of thermally-treated ash (Fraxinus excelsior L) and European beech (Fagus sylvatica L) against subterranean termites (Reticulitermes banyulensis) was evaluated. A laboratory no-choice feeding test following the standard EN 177 was performed to assess the efficacy of this thermo-modification against subterranean termites in the Mediterranean area. After 8 weeks period of exposure, results showed that durability against termites was slightly improved for thermally-treated beech wood, which was classified as moderately durable. However, in case of thermally-treated ash wood, samples were highly biodegraded by termites, revealing no increase in their durability and being classified as non durable. 相似文献
Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood® treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 °C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 °C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation. 相似文献
This study determined the functional and different biological activities of casein glycomacropeptide (GMP) after conjugation with fatty acids. Medium (i.e. caproic, lauric and myristic acid) and long (i.e palmitic and stearic acid) fatty acids were conjugated to GMP at the available amino group. Functionalities of lipophilized GMP conjugates included foaming and emulsifying activities, and biological activities for bacterial growth inhibition, cell damage and anti-invasion. Greater lipophilization of GMP was achieved with medium chain fatty acids (p < 0.05), which resulted in reduced GMP solubility regardless of fatty acid conjugate. Foaming activity of GMP was lost after lipophilization, but emulsification activity of GMP was enhanced (p < 0.05). A parallel increase in growth inhibition of Salmonella spp. coupled with anti-invasion of Salmonella enteritidis (Inv A) into mammalian cells was induced by lipophilization of GMP with long chain fatty acid. Our results show that GMP modified by lipophilization with specific fatty acids provides improved functionality as a surfactant with enhanced antibacterial activity towards gram negative bacteria. 相似文献
A modified essential amino acid index equation incorporating a digestibility factor (MEAAI), and a chemical score index (CSI) were developed from the essential amino acid profile of 18 different food proteins hydrolysed by the combined but sequential action of papain and pronase E enzyme systems. The essential amino acid composition of whole egg was used as a reference standard. The following equations were proposed. In which a is the value of the limiting amino acid in the sample, and ae is the corresponding value in whole egg. Both equations were used to calculate the biological value of different protein foodstuffs. There was a close agreement between values obtained using the equations and reported values for the same foodstuffs published in the literature. There was also a close correlation (r = 0.665) between data obtained using MEAAI and those obtained using CSI in estimating biological values, suggesting that either equation could be used reliably and solely to estimate protein biological value of foods. 相似文献
Beef steaks were treated with 1.5% lactic acid alone or supplemented with antioxidants (0.1% rosemary extract and 0.05% ascorbic acid). The steaks were stored under modified atmospheres containing either 60% O2/40% CO2 or 70% O2/20% CO2/10% N2. Both the 40% CO2 atmosphere and the lactic acid treatment significantly (P<0.05) inhibited growth of lactic acid bacteria, Brochothrix thermosphacta and Pseudomonas spp. Neither CO2 in the pack atmosphere, treatment with lactic acid, nor a combination of both, affected formation of thiobarbituric acid reactive substances, myoglobin oxidation, or CIE a* values. However, treatment with antioxidants significantly (P<0.05) delayed oxidation of both myoglobin and lipids, and so extended the storage-life. 相似文献
Maize with a modified amino acid profile, i.e. greater amounts of lysine and tryptophan than normal, is known as ‘quality protein maize’ (QPM). The objective of this work was to find the best combination of extrusion process variables to produce QPM flour for making tortillas. QPM grits were mixed with lime and water and had a moisture content of 28%. The single screw extruder operation conditions were selected from factorial combination of three process variables: extrusion temperature (ET, 70–100 °C), lime concentration (LC, 0.1–0.3% of the maize weight) and screw velocity (SV, 80–250 rpm). Response surface methodology was used as an optimization technique. In vitro protein digestibility (PD); total colour difference (ΔE) of the flours, and tortilla puffing (TP) were chosen as response variables. A graphical method was used to obtain maximum PD, TP and minimum ΔE. The optimum combination of process variables was: ET = 85 °C/LC = 0.21%(w/w)/SV = 240 rpm. Tortillas from QPM flour had similar chemical composition, physicochemical and sensory properties to tortillas from commercial nixtamalized maize flour; however, the former had the highest (P ≤ 0.05) available lysine content and were therefore better nutritionally. 相似文献
This study seeks to assess the potential use of the CIEDE2000 color difference equation in wood science. Therefore, a set of oak wood samples were prepared and assessed by experts. The visual perception of the observers was correlated with the two different color difference equations CIELAB from DIN 6174 and the CIEDE2000 equation. For a practical example two different types of wood were bleached and exposed to UV-light. The results showed that the CIEDE2000 equation outperformed the CIELAB equation. The CIELAB equation showed generally an overestimation of the color change (ΔE) for wood applications, compared to the nontrivial CIEDE2000 equation from 2001. 相似文献