| dc.contributor.author | Jin, Yulai. | en_US |
| dc.date.accessioned | 2014-10-21T12:38:00Z | |
| dc.date.available | 2002 | |
| dc.date.issued | 2002 | en_US |
| dc.identifier.other | AAINQ77594 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55884 | |
| dc.description | Behaviour of barley beta-(1 → 3)(1 → 4)-D-glucans in wort and beer was examined to investigate their effect on brewing process and beer quality. Beta-glucans at 0--1000 mg/L increased wort and beer viscosity linearly with MW and concentration. The Arrhenius relationship governed the effect of temperature on wort viscosity. Beta-glucan viscosity in wort was lowered after shearing although shearing increased the apparent wort viscosity (p < 0.001). Shearing decreased beer viscosity (p < 0.001) but did not affect the beta-glucan viscosity in beer (p > 0.05). Shearing temperature did not affect the viscosities of wort or beer (p > 0.05). Increasing pH raised wort viscosity (p < 0.001) but did not affect beer viscosity (p > 0.05). Maltose in wort and ethanol in beer enhanced the viscosity of beta-glucan polymers (p < 0.001). Beta-glucan-caused viscosity was found to be an indicator of potential technical problems. Beta-glucans had higher intrinsic viscosities (5°C) in beer than in wort (p < 0.001). The critical overlap concentration (C*) for beta-glucans (31--443 kDa) in beer and wort was found to vary in the range of 1.3--8.3 g/L. | en_US |
| dc.description | Apparent particle size of beta-glucans in wort and beer increased with their MW and concentration (p < 0.001). Beta-glucans had greater particle size in beer (mainly 0.01--0.1 mum in diameter) than in wort (even distributed in <0.01 mum and >0.01 mum fractions) (p < 0.001). Beta-glucan particles were larger at higher pHs of wort and beer (p < 0.001). Maltose did not affect the beta-glucan particle size distributions in wort (p > 0.05). High ethanol concentrations increased the 0.01--0.1 mum fraction and decreased the >0.1 mum fraction of the 443 kDa beta-glucan in beer (p < 0.001). Shearing of wort and beer resulted in a decrease in the <0.01 mum fraction of beta-glucans and an increase in 0.01--0.1 mum beta-glucan fraction (p < 0.001) but shearing temperature did not affect the particle size distribution (p > 0.05). | en_US |
| dc.description | Wort and beer turbidity increased with higher MWs and concentrations of beta-glucans (p < 0.001), shearing (p < 0.001), lower maltose and ethanol levels and lower pHs (p < 0.001). Shearing (20--76°C) at high temperatures resulted in lower wort turbidity values than low temperatures (p < 0.001) but shearing temperature (0--10°C) did not affect beer turbidity (p > 0.05). (Abstract shortened by UMI.) | en_US |
| dc.description | Thesis (Ph.D.)--DalTech - Dalhousie University (Canada), 2002. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Agriculture, Food Science and Technology. | en_US |
| dc.title | Effect of beta-glucan and environmental factors on the physical and chemical properties of wort and beer. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
