Production and characterisation of gluten-free chestnut sourdough breads

The impact of sourdough amount (20, 40 and 60%) on the rheological behaviour of gluten-free chestnut-rice dough formulations and quality parameters (pH, total titratable acidity, firmness, volume and crumb microstructure) of the corresponding breads was studied. The addition of sourdough led to decreases in complex modulus indicating a softening of the dough samples. Higher levels of sourdough addition had a detrimental effect on the volume and texture of breads. X-ray micro computed tomograph images showed that gluten-free chestnut-rice breads prepared with a sourdough incorporation of 20% had the most homogenous structure with high number of smaller pores. Inferior crumb structures were observed with the further addition of sourdough. Confocal laser scanning microscopy revealed that the proteins in breads prepared with sourdough were smaller due to their degradation into smaller peptides by the sourdough fermentation. These changes resulted in an improvement of the bread quality

The advantage of channeling nucleotides for very processive functions

Nucleoside triphosphate (NTP)s, like ATP (adenosine 5’-triphosphate) and GTP (guanosine 5’-triphosphate), have long been considered sufficiently concentrated and diffusible to fuel all cellular ATPases (adenosine triphosphatases) and GTPases (guanosine triphosphatases) in an energetically healthy cell without becoming limiting for function. However, increasing evidence for the importance of local ATP and GTP pools, synthesised in close proximity to ATP- or GTP-consuming reactions, has fundamentally challenged our view of energy metabolism. It has become evident that cellular energy metabolism occurs in many specialised ‘microcompartments’, where energy in the form of NTPs is transferred preferentially from NTP-generating modules directly to NTP-consuming modules. Such energy channeling occurs when diffusion through the cytosol is limited, where these modules are physically close and, in particular, if the NTP-consuming reaction has a very high turnover, i.e. is very processive. Here, we summarise the evidence for these conclusions and describe new insights into the physiological importance and molecular mechanisms of energy channeling gained from recent studies. In particular, we describe the role of glycolytic enzymes for axonal vesicle transport and nucleoside diphosphate kinases for the functions of dynamins and dynamin-related GTPases