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Stabilization of mineral oil hydrocarbons in recycled paper pulp by organo-functionalized mesoporous silicas and evaluation of migration to food

Buscaroli, Enrico, Bussini, Daniele, Bisio, Chiara, Montecchio, Daniela, Elegir, Graziano, Garbini, Davide, Marchese, Leonardo, Braschi, Ilaria
European food research & technology 2017 v.243 no.8 pp. 1471-1484
food industry, hydrocarbons, mineral oil, packaging, paper, paper pulp, paperboard, papermaking, pigments, porous media, recycled paper, silica, solvents, sorbents, washing, wheat, wheat flour
The occurrence of mineral oil hydrocarbons (MOH) in cellulose-based packaging is mainly due to the offset printing process where MOH are used as a ink pigments’ solvent. The MOH migration from paper/paperboard to food is matter of concern for EFSA, members state authorities, consumers, and food industry. In this study, the feasibility to stabilize MOH by adding a sorbent into recycled paper obtained through a common washing process was investigated and the migration to wheat flour/Tenax® assessed. Among several white/pale yellow porous materials, organo-modified powder silica MCM-41-Si(CH₃)₃ showed the best combination between affinity for MOH (184% dw) and stability to thermal regeneration. A freshly issued newspaper with >3000 mg MOH kg⁻¹ was used to produce recycled paper at a laboratory-scale plant. MCM-41-Si(CH₃)₃ was added at the pulping step (1% dw) and the sorbent-enriched pulp handled according to a washing paper production process with no effect on the paper optical brightness. The MOH content of the wheat flour in contact with the sorbent-enriched paper under accelerated migration conditions (15 days at 40 °C) resulted 20% of that contacted with control paper (4.3 ± 1.1 and 20.4 ± 5.5 mg kg⁻¹, respectively), despite its contamination was 24% higher than the control. On the contrary, Tenax® contamination resulted 56.0 ± 10.0 and 47 ± 14.0 mg kg⁻¹ when exposed to sorbent-enriched and control paper, respectively.