The effects of size, temperature and air contact on the outcome of heating oak fragments

The concentrations of the important oak aroma volatiles guaiacol, 4-methylguaiacol cis- and trans-oak lactone and vanillin in extracts of French and American oak heated under various conditions were measured using stable isotope dilution analyses coupled with gas chromatography-mass spectrometry. Heating resulted in marked increases in the concentrations of guaiacol, 4-methylguaiacol and vanillin, with more formed at higher temperature. Approximately twice as much guaiacol and 4-methylguaiacol and two to five times as much vanillin were formed by heating in the presence of air compared to heating under argon. Oak lactone concentration was less affected by heating. The effects of heating different sized oak pieces were investigated for French and American oak samples. Compared to heating larger oak pieces, heating smaller fragments of oak generated up to twice as much guaiacol and 4-methylguaiacol and two to four times as much vanillin at 235oC for both French and American oak. This effect is ascribed to the exposure of a greater surface area of oak to air when smaller fragments are heated. Variable effects were observed for cis- and trans-oak lactone. Variation in chip size, as well as heating time and temperature, is clearly one way of obtaining different aroma profiles from oak products.J.I. Campell, M. Sykes, M.A. Sefton and A.P. Pollnit

Regulation of PKCβ levels and autophagy by PML is essential for high-glucose-dependent mesenchymal stem cell adipogenesis

Obesity is a complex disease characterized by the accumulation of excess body fat, which is caused by an increase in adipose cell size and number. The major source of adipocytes comes from mesenchymal stem cells (MSCs), although their roles in obesity remain unclear. An understanding of the mechanisms, regulation, and outcomes of adipogenesis is crucial for the development of new treatments for obesity-related diseases. Recently an unexpected role for the tumor suppressor promyelocytic leukemia protein (PML) in hematopoietic stem cell biology and metabolism regulation has come to light, but its role in MSC biology remains unknown. Here, we investigated the molecular pathway underlying the role of PML in the control of adipogenic MSC differentiation