Kraft Cooking with Teak Wood Extract and Determining Residual 2-Methylanthraquinone in Eucalyptus Pulp

Abstract

Anthraquinone (AQ) is used in the pulp and paper industries as a cooking catalyst. However, because AQ is "possibly carcinogenic", it is no longer approved in Germany for the manufacture of paper and paperboard that contact food. To address this problem, we examined 2-methylanthraquinone (2-MAQ) , a natural anthraquinone from teak (Tectona grandis) wood. Eucalyptus globulus wood was subjected to kraft cooking at 145℃ for 3 h with 0.03％ 2-MAQ and 15-19％ active alkali to provide pulp in 55.5-58.1％ yield. Kraft cooking with the acetone extract of Myanmar teak wood increased pulp yield by 1.6％ but decreased kappa number by two points compared to that with only 2-MAQ. Ames testing suggests that 2-MAQ is not mutagenic. Unbleached and oxygen-bleached pulp contained 0.40-2.90 ppm and 0.21-0.39 ppm residual 2-MAQ, respectively, while 2-MAQ was not detected in fully bleached pulp; therefore, this pulp should be safe for food-packaging use.

Mutagenicity of Tectona grandis Wood Extracts and Their Ability to Improve Carbohydrate Yield for Kraft Cooking Eucalyptus Wood

“…Compound C was identified as 2-MAQ by comparison with authentic 2-MAQ using GC/MS. Thus, the 2-MAQ content determined from the calibration curve was 0.18% based on the wood weight for Indonesia teak wood ( Table 2 ) compared with 0.21% in Myanmar teak wood [ 17 ].…”

“…The quantity of 2-MAQ transferred to food is 0.01 mg/kg of food when the maximum amount of residual 2-MAQ in pulp is 8 mg/kg [ 17 ]. The above results showed a maximum residue of 6.00 mg/kg, indicating that the quantity of 2-MAQ transferred to food was a maximum of only 0.0075 mg/kg.…”

“…Determining the residual 2-MAQ in bleached pulp used for food wrapping and packaging materials is also important. A previous study [ 17 ] clarified that the residual 2-MAQ content in oxygen-bleached pulp was 0.2–0.3 mg/kg based on pulp weight. No residual 2-MAQ was detected in the final bleached pulp determined by GC/MS [ 17 ].…”

“…A previous study [ 17 ] clarified that the residual 2-MAQ content in oxygen-bleached pulp was 0.2–0.3 mg/kg based on pulp weight. No residual 2-MAQ was detected in the final bleached pulp determined by GC/MS [ 17 ].…”

“…The acetone extracts of Myanmar teak wood were mutagenic (positive) against S. typhimurium strain TA 100 with 10% rat S9, but the response to strain TA 98 was not detectably mutagenic [ 17 ]. Figure 1 shows that the contents of deoxylapachol and its isomers (compounds A and B ) in Myanmar extracts were trace and probably less than one-80th (1.25%) of those of Indonesia extracts.…”