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The paper reports the influence of an ethanol emitter (Ethicap) on the microbiological condition and the shelf life extension of a bakery product. Pre-baked buns, with a water activity of 0.95, were packaged with different amounts of Ethicap and stored at room temperature. Yeasts and moulds remained largely absent from the core of the pre-baked bun (< 10(2) cfu g(-1)) during storage, independent of the presence of ethanol. The total mesophilic count was low at the beginning of the storage experiment (< 10(2) cfu g(-1)), but increased without ethanol within 1 week to an unacceptable level. In the presence of ethanol, the total mesophilic count stabilizes at a consumable level of 10(5)-10(6) cfu g(-1). The increase of total mesophilic count was caused by growth of a Bacillus spp., probably B. subtilis. Mould growth on the outer surface is limiting for shelf life extension. On the pre-baked buns, the following moulds were present: Penicillium solitum, P. commune, P. corylophilum, Cladosporium sphaerospermum and C. herbarum. These started to grow within 4-6 days. Mould growth can be delayed for 13 days by adding Ethicap. The ethanol probably has to be absorbed by the pre-baked bun to be effective in growth suppression of the Bacillus spp. the moulds. The pre-baked buns absorb most of the ethanol from the package headspace, and the ethanol content of the products is approximately 0.8 weight% after 21 days. This largely exceeds the overall migration limit of 60 mg kg(-1) food (0.006 weight%).

The nucleation of poly(ethylene terephthalate) (PET) by codiols and olefinic segments was studied. The codiols 1,5-pentanediol, 1,8-octanediol, 2,5-hexanediol, and 1,3-dihydroxymethyl benzene were copolymerized into PET in a concentration range of 0 -10 mol %. The melting (T m ), crystallization (T c ), and glass-transition (T g ) temperatures were studied. These codiols were found to be able to nucleate PET at low concentrations, probably by lowering the surface free energy of the chain fold. However, the codiols also disturbed the structural order of the polymer, resulting in a decrease in both the T m and T c values. The optimum codiol concentration was found to be at around 1 mol %, which is lower than previously reported. A diamide segment N,NЈ-bis(p-carbomethoxybenzoyl)ethanediamine (T2T) was found to be a more effective nucleator than the codiols; however, no synergy was observed between the nucleating effect of the diamide segment T2T and that of the codiol. An olefinic diol (C 36 -diol) with a molecular weight of 540 g/mol was also copolymerized into PET in a concentration range of 0 -21 wt %. Only one T g was observed in the resulting copolymers, suggesting that the amorphous phases of PET and the C 36 -diol are miscible. The main effect of incorporating the C 36 -diol into PET was the lowering of the T g ; thus, the C 36 -diol is an internal plastifier for PET. The C 36 -diol had little effect on the T m value; however, the T c value actually increased in the 11.5 wt % copolymer. As the T g decreased and the T c increased, the crystallization window also increased and thereby the likelihood of crystallization. Therefore, the thermally stable C 36 -diol appears to be an interesting compound that may be useful in improving the crystallization of PET.

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