1,218 research outputs found
Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
No full textAuthor also known as SM LovedayFresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism
On the stability of the disordered molecular alloy phase of ammonia hemihydrate
No full textThe disordered-molecular-alloy phase (DMA) of ammonia hydrates [J.S. Loveday and R. J. Nelmes, Phys. Rev. Lett. 83, 4329 (1999)] is unique in that it has substitutional disorder of ammonia and water over the molecular sites of a body centred cubic lattice. Whilst this structure has been observed in ammonia di- and mono-hydrate compositions, it has not been conclusively observed in the ammonia hemihydrate system. This work presents investigations of the structural behaviour of ammonia hemihydrate as a function of P and T. The indications of earlier studies [Ma et al. RSC Adv. 2, 4290 (2012)] that the DMA structure could be produced by compression of ammonia hemihydrate above 20 GPa at ambient temperature are confirmed. In addition, the DMA structure was found to form reversibly both from the melt, and on warming of ammonia hemihydrate phase-II, in the pressure range between 4 and 8 GPa. The route used to make the DMA structure from ammonia mono-and di-hydrates-compression at 170 K to 6 GPa followed by warming to ambient temperature-was found not to produce the DMA structure for ammonia hemihydrate. These results provide the first strong evidence that DMA is a thermodynamically stable form. A high-pressure phase diagram for ammonia hemihydrate is proposed which has importance for planetary modelling. (C) 2015 AIP Publishing LLC.</p
Mobile polling and the Aboriginal vote: The federal election
No full textThe study reported in this volume was conducted with the permissions and support of the Australian Electoral Commission and it is published as a report to the Commission. Similar reports on mobile polling in the 1980 and 1983 Northern territory elections - under Territory legislation - have been published in Dean Jaensch and P Loveday, eds, Under One Flag, The 1980 Northern Territory Election (George Allen and Unwin and NARU, 1981) and in P. Loveday and Dean Jaench, eds, A Landslide Election, The NT1983 (NARU, 1984). The arrangement with the Electoral Commission gave NARU observes official status with the polling teams. Detailed preparations for accompanying the polling teams were worked out with Divisional Returning Officers or their deputies in Queensland, the Northern Territory and Western Australia. We wish to acknowledge the unstinting cooperation of David Muffett, Terry Emerson, Brian Howard and Danny Wallace and the general support given by Andrej Cirulis. The careful work of the observers should also be acknowledged: Deborah Wade-Marshall, Raelene Cummings, Rolf Gerritsen, Ciaran O'Faircheallaigh, will Sanders, Wayne Mollah and Scott Cane. And the work of support staff in NARU who prepared the manuscript - Elaine Sommer, Denise Goodfellow and Robyn Darben - is also acknowledged with thanks. The author was also one of the observers and, with help from Deborah Wade-Marshall, coordinator of the observer team
Hiatus or Hidden? The Problem of the Missing Scottish Upland Cursus Monuments
No full textThis paper explores the possibility of cursus monuments being located in upland locations in Britain. These rectangular enclosures date to the Early Neolithic, and are almost all known as cropmark sites in lowland river valley contexts. However, Loveday explores various examples where upland upstanding features such as field banks could have prehistoric origins and easily be misinterpreted. Evidence from three case-study areas in Scotland – Upper Strathearn and Strathtay, Nithsdale, and the Biggar Area – is covered in detail to suggest a context for, and likely location of, possible upland cursus monuments. This is then placed with an upland British context, and the chapter concludes with news of a recent discovery that vindicates the approach of the author.</p
The optimal design for a ground cooling tube in a hot, arid climate
No full textAl-Ajmi developed a TRNSYS model of a ground cooling tube as a PhD project (co-supervised by Hanby and Loveday). Hanby translated the model into Matlab, combined it with an evolution strategy optimization and carried out the search for optimal designs. Hanby was the lead author
QJE-STD_17-196.R2-Supplementary_Material – Supplemental material for Positivity bias in past and future episodic thinking: Relationship with anxiety, depression, and retrieval-induced forgetting
No full textSupplemental material, QJE-STD_17-196.R2-Supplementary_Material for Positivity bias in past and future episodic thinking: Relationship with anxiety, depression, and retrieval-induced forgetting by L Marsh, T Edginton, MA Conway and C Loveday in Quarterly Journal of Experimental Psychology</p
FMRI/ERP of musical syntax: comparison of melodies and unstructured note sequences.
No full textTo date, the neural correlates of musical syntax processing have been investigated mainly by means of paradigms in which isolated chords are made incongruent with the harmonic context. Here, we present results obtained contrasting unfamiliar one-part piano melodies with unstructured note sequences, comparable in pitch and rhythm but devoid of any syntactic structure. This paradigm indexes a superset of the cognitive functions involved in processing of harmonic rules. Using functional magnetic resonance imaging, differential activation of a bilateral cortical network comprising the inferior frontal gyrus, superior temporal gyrus and premotor cortex was found. Using event-related potentials, the N2 evoked by each note in melodies was found to have longer latency and a more frontal distribution than that evoked in unstructured sequences
Functional MRI/event-related potential study of sensory consonance and dissonance in musicians and nonmusicians
No full textPleasurability of individual chords, known as sensory consonance, is widely regarded as physiologically determined and has been shown to be associated with differential activity in the auditory cortex and in several other regions. Here, we present results obtained contrasting isolated four-note chords classified as consonant or dissonant in tonal music. Using event-related functional MRI, consonant chords were found to elicit a larger haemodynamic response in the inferior and middle frontal gyri, premotor cortex and inferior parietal lobule. The effect was right lateralized for nonmusicians and less asymmetric for musicians. Using event-related potentials, the degree of sensory consonance was found to modulate the amplitude of the P1 in both groups and of the N2 in musicians only
- …
