Search

Examines the behavior of tip vortex in an axial fan without casing wall. Velocity measurement; Vorticity distribution; Tip vortex flow; Leading edge vortex.

Examines the unsteady flow field with rotating stall cells in high specific-speed diagonal flow fan. Characteristics of stall cells; Propagation speed of 80 percent rotor speed; Application of double phase-locked averaging technique on the processing of data; Assessment on the behavior of rotating stall cell with velocity component.

Contents of fructo-oligosaccharides and fructo-polysaccharides and activities of fructosyltransferases and invertase in asparagus roots harvested between July and November were studied by gel permeation chromatography (GPC) and high performance liquid chromatography (HPLC). Contents of total sugar and fructo-oligosaccharides and fructo-polysaccharides were very low in July, and then increased until September. During this period, sucrose accumulated first, second trisaccharides, and then tetra-, penta- and higher-saccharides increased in that order. 1-Kestose was the most predominant fructo-oligosaccharide isomer [degree of polymerization (DP) 3 ∼ 6]. The fructo-polysaccharide of DP ⩾ 9 was 12.8 ∼ 21.7 % of total sugar from September to November; polysaccharides estimated to be DP 20 ∼ 22 were just detectable. SSTF activities were very low in July, rose to a maximum in September and then decreased. Change in activity of SST was responsible for change in contents of sucrose and 1-kestose from July to November. 1F- fructosyltransferase (1F-FT) activities increased until September, were almost constant from October to November and then decreased slightly 6°-fructosyltransferase (6°-FT) reached its highest activity early in October, 6F-SST (6-kestose producing enzyme) activity was very slight from July to November and was ∼ 1/1000 of SST activity in September. This activity does not contribute to the enzymatic synthesis of the saccharides of asparagus roots. Invertase activity was nearly constant throughout. The change of activities of SST, 1F-FT and 6°-FT paralleled closely the accumulation of sucrose, 1-kestose, neokestose and other saccharides. In vitro synthesis of fructo-oligosaccharides from sucrose at 0.4, 0.1 and 0.05 M, or from 1-kestose was investigated in a fraction prepared from asparagus roots harvested in September. 1-Kestose was investigated in a fraction prepared from asparagus roots harvested in September. 1-Kestose (isokestose, 3a), neokestose (3b), nystose (4a), 1F (1-B-D-fructofuranosyl)m-6(1-B-D-Fructofuranosyl)-Sucrose (4b: m = 0, n = 2; 4c: m = 1, n = 1, 5a: m = 3, n = 0; 5b m = 0, n = 3; 5c: m = 2, n = 1; 5d: m = 1, n = 2) and a mixture of hexasaccharide-isomers were synthesized from 0.4M source in 60h. In 0.05 and 0.1 M source unidentified heptasaccharides were also produced. Octa- and higher-saccharide, as well as the saccharides synthesized from sucrose, were also produced. Octa- and higher-saccharide, as well as the saccharides synthesized from sucrose, were formed from 0.1 M 1-kestose. All of the saccharides synthesized from sucrose or 1-kestose by the asparagus enzyme preparation were identical to saccharides occurring naturally in the roots of asparagus. [ABSTRACT FROM AUTHOR]

About 80 percent of onion bulb dry matter is non-structural carbohydrates. These carbohydrates are predominantly glucose, fructose, sucrose and low-molecular weight fructans, while starch and raffinose are absent. The metabolism of sugars is closely linked to the dormancy and sprouting state, and the most important biochemical change occuring during post-harvest life of bulbs, as with other vegetables, is the content variation in the carbohydrate constituents.

Abstract: Burdock roots were stored for six weeks at three temperatures, 0, 15 and 20°C, and activity of sucrose hydrolase (SH), 1-kestose hydrolase (1-KH), inulin hydrolase (InH), sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructoslytransferase (1-FFT) were assessed. Simultaneously, total fructooligosaccharides (FOS), total inulooligosaccharides (IOS) and inulin were also assessed during storage. During storage, SH showed an irregular variation at 15 and 20°C, and was significantly higher at 0°C showing a continuous increase during the storage period. 1-KH decreased progressively at 15 and 20°C, but showed a sharp increase at 0°C after two weeks and decreased afterwards. InH showed a different although more regular pattern by decreasing progressively at 0, 15 and 20°C. However, the decrease was more significant at 15 and 20°C during the first two weeks, while at 0°C the decrease was significant after four weeks storage. 1-SST and 1-FFT activities decreased progressively in a pseudo-linear regression during storage, and showed similar patterns. At 15 and 20°C, total FOS increased during the first three weeks then decreased, while at 0°C FOS increased progressively during storage. Total IOS increased during storage, however, this increase was much higher at 0°C than that observed at 15 and 20°C. Inulin content decreased during storage and final content was lower at 20°C. The inulin to total FOS plus total IOS ratio decreased sharply during the first two weeks of storage, then progressively during the last four weeks, while the ratio of hydrolyzing to synthesizing activities was quite stable at 15 and 20°C, but showed a peak at 0°C after two weeks. The results suggest that carbohydrate metabolism in stored burdock depends partly on temperature and other physiological factors. [Copyright &y& Elsevier]

Recently we found that some nucleosides such as inosine or adenosine inhibited alpha-glucosidase from rat intestine. The aim of this study was to determine whether these nucleosides are sucrase inhibitors in humans as well as rats. Blood glucose and insulin responses were examined in 23 healthy volunteers (18 males and 5 females) administered sucrose with inosine and 8 (males) administered sucrose with adenosine. The initial increase in plasma glucose and serum insulin concentrations at 30 min after loading sucrose (50 g) alone were significantly reduced by co-administration of inosine (2.5 and 1.0 g) or adenosine (2.5 g). The total increases in the areas under the plasma glucose and serum insulin concentration curves for 3 h after administration of the same amount of sucrose with inosine were also significantly less than those when the volunteers were administered sucrose alone. These results in humans agree with the findings obtained in our previous studies in rats. These nucleosides may be used as one of the components of artificial sweeteners when mixed with sucrose and may be useful as food additives to suppress increases in blood glucose and insulin. [ABSTRACT FROM AUTHOR]