Using the Scanning Fluid Dynamic Gauging Device to Understand the Cleaning of Baked Lard Soiling Layers

Extended or repeated heating of food fats promotes polymerisation reactions that produce difficult-to-remove soil layers. Cleaning of these baked-on/burnt-on fat deposits was investigated using model layers generated by baking lard on 316 stainless steel discs. Rigorous characterisation of the layer material was difficult, as it was insoluble in most solvents. Cleaning was studied using the scanning fluid dynamic gauging technique developed by Gordon et al. (Meas Sci Technol 21:85-103, 2010), which provides non-contact in situ measurement of layer thickness at several sites on a sample in real time. Tests at 50 [Formula: see text]C with alkali (sodium hydroxide, pH 10.4-11) and three surfactant solutions indicated two removal mechanisms, related to the (1) roll-up and (2) dispersion mechanisms reported for oily oils, namely (1) penetration of solvent at the soil-liquid interface, resulting in detachment of the soil layer as a coherent film, observed with linear alkylbenzene sulfonic acid (LAS) and Triton X-100 and aqueous sodium hydroxide at pH 10.4-11; and (2) the breakdown promoted by the agent penetrating through the layer, observed with cetyl trimethyl ammonium bromide (CTAB), in which CTAB antagonised the cleaning action of LAS.An EPSRC studentship for AA and project support from Procter and Gamble Ltd is gratefully acknowledged.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s11743-015-1737-

Rhizobia with 16S rRNA and nifH Similar to Mesorhizobium huakuii but Novel recA, glnII, nodA and nodC Genes Are Symbionts of New Zealand Carmichaelinae

New Zealand became geographically isolated about 80 million years ago and this separation gave rise to a unique native flora including four genera of legume, Carmichaelia, Clianthus and Montigena in the Carmichaelinae clade, tribe Galegeae, and Sophora, tribe Sophoreae, sub-family Papilionoideae. Ten bacterial strains isolated from NZ Carmichaelinae growing in natural ecosystems grouped close to the Mesorhizobium huakuii type strain in relation to their 16S rRNA and nifH gene sequences. However, the ten strains separated into four groups on the basis of their recA and glnII sequences: all groups were clearly distinct from all Mesorhizobium type strains. The ten strains separated into two groups on the basis of their nodA sequences but grouped closely together in relation to nodC sequences; all nodA and nodC sequences were novel. Seven strains selected and the M. huakuii type strain (isolated from Astragalus sinicus) produced functional nodules on Carmichaelia spp., Clianthus puniceus and A. sinicus but did not nodulate two Sophora species. We conclude that rhizobia closely related to M. huakuii on the basis of 16S rRNA and nifH gene sequences, but with variable recA and glnII genes and novel nodA and nodC genes, are common symbionts of NZ Carmichaelinae. © 2012 Tan et al