In cheese, a negative oxidation-reduction (redox) potential is required for the stability of aroma, especially that associated with volatile sulphur compounds. To control the redox potential during ripening, redox agents were added to the salted curd of Cheddar cheese before pressing. The control cheese contained only salt, while different oxidising or reducing agents were added with the NaCl to the experimental cheeses. KIO3 (at 0·05, 0·1 and 1%, w/w) was used as the oxidising agent while cysteine (at 2%, w/w) and Na2S2O4 (at 0·05 and 0·1%, w/w) were used as reducing agents. During ripening the redox potential of the cheeses made with the reducing agents did not differ significantly from the control cheese (Eh ≈ −120 mV) while the cheeses made with 0·1 and 0·05% KIO3 had a significantly higher and positive redox potential in the first month of ripening. Cheese made with 1% KIO3 had positive values of redox potential throughout ripening but no starter lactic acid bacteria survived in this cheese; however, numbers of starter organisms in all other cheeses were similar. Principal component analysis (PCA) of the volatile compounds clearly separated the cheeses made with the reducing agents from cheeses made with the oxidising agents at 2 month of ripening. Cheeses with reducing agents were characterized by the presence of sulphur compounds whereas cheeses made with KIO3 were characterized mainly by aldehydes. At 6 month of ripening, separation by PCA was less evident. These findings support the hypothesis that redox potential could be controlled during ripening and that this parameter has an influence on the development of cheese flavour.

Magnesium (Mg) plays an important role in the body mediating cell-extracellular matrix (ECM) interactions, bone apatite structure and density, and nucleic acid chemistries. While Mg has been investigated as a biomaterial for bone applications, it has not been studied for applications within soft tissues. This study investigated, for the first time, the response of fibroblasts to magnesium oxide (MgO) nanoparticles for soft tissue engineering applications. Primary human dermal fibroblasts were cultured both on tissue culture polystyrene in media supplemented with MgO nanoparticles as well as on poly-L-lactic acid (PLLA)-MgO nanoparticle composites. As this study was conducted concurrently with a study aimed at bone tissue engineering, hydroxyapatite (HA) nanomaterials were used for comparison. Results showed for the first time that fibroblasts adhered onto MgO-containing composites roughly three times better than HA-PLLA samples and roughly 4.5 times better than plain PLLA samples. Fibroblasts also proliferated to statistically higher densities when cultured in medium supplemented with MgO nanoparticles compared to un-supplemented medium and medium supplemented with HA nanoparticles. These preliminary results together suggest that MgO nanoparticles should be further investigated as materials to improve the regeneration of soft tissues as well as bone.