Volatile Compounds in Crumb of Whole‐Meal Wheat Bread Fermented with Different Yeast Levels and Fermentation Temperatures

The influence of fermentation temperatures (8, 16, and 32°C) and yeast levels (2, 4, and 6%) on the formation of volatile compounds in the crumb of whole‐meal wheat bread was investigated. Volatile compounds were extracted by dynamic headspace extraction and analyzed by gas chromatography–mass spectrometry. Results were evaluated with multivariate data analysis and ANOVA. Bread fermented at a high temperature (32°C) had higher peak areas of the Maillard reaction products 2‐furancarboxaldehyde, 2‐acetylfuran, 2‐methylpyrazine, and phenylacetaldehyde compared with bread fermented at lower fermentation temperatures. Bread fermented at low temperatures (8 and 16°C) was characterized by having higher peak areas of the fermentation products 3‐methylbutanal, 2‐methylbutanal, ethyl acetate, ethyl hexanoate, ethyl propanoate, and 3‐methylbutanol. Fermentation of bread with 6% yeast resulted in a higher peak area of the important fermentation product 2‐phenylethanol. It also reduced the peak areas of important lipid oxidation products. The peak area of 2,3‐butanedione was also relatively higher in bread fermented with 6% yeast compared with lower yeast levels; however, an interaction was seen between the high yeast level and all three fermentation temperatures. In contrast, fermentation with a low yeast level (2%) resulted in bread with relatively higher peak areas of 2‐ and 3‐methylbutanal, as well as (E)‐2‐nonenal and (E,E)‐2,4‐decadienal, which are important lipid oxidation compounds in bread.     

Cultivar and year-to-year variation of phytosterol content in rye (Secale cereale L.)

Intake of phytosterols (and -stanols) has been shown to decrease the level of low-density lipoprotein cholesterol and thus protect against development of cardiovascular diseases. Therefore, studies on the cultivar and year-to-year variation in phytosterol content in rye grains have been performed. The phytosterol content and composition of different rye cultivars, grown under identical conditions on the same field in three consecutive years, were analyzed. Both cultivar and year-to-year variation in sterol content were statistically significant (p < 0.0001). The total sterol content varied from 1007 +/- 21 mg/kg in the highest yielding cultivar, Tsulpan 3, to 761 +/- 10 mg/kg in the lowest yielding cultivar (Amando in the 1999 harvest). Because the meteorological conditions varied substantially between the different years, it was possible to deduce the impact of varying weather conditions on phytosterol content in the different cultivars. The studied cultivars had all the lowest phytosterol contents in the dry and warm harvest season of 1999. Although there were statistically significant cultivar and year-to-year variations in the sterol composition (p < 0.0001), these were only between 2 and 4% of the total sterol content.     

Throughfall and canopy buffering in three sitka spruce stands in Denmark

Throughfall was studied in three even-aged sitka spruce stands in Denmark during the years 1989 to 1994. Deposition of sea salts dominated the fluxes of substances in varying degrees between years and sites. During the study period, non-marine S deposition did not change substantially. At the site most affected by animal husbandry, fluxes of NH₄ ⁺ and NO₃ ^? increased over the years. Elevated fluxes of TOC, K⁺, and PO₄ ^3? occurred in the growing season due to canopy leaching caused by attacks by the green spruce aphid. Fluxes of Cl^?, SO₄ ^2?, Na⁺, Ca²⁺, and Mg²⁺ were highest in the dormant season. Buffering of. pH was affected by the nitrogen dynamics in the canopy, and also, at least during the summer, by elevated levels of organic compounds.     

Characterization of peptides formed during fermentation of cocoa bean.

Analysis by SDS-PAGE and GPC-MS of fermented cocoa extracts shows changes in the amount and composition of the major proteins, accompanied by formation of complex distributions of peptides. MS/MS studies and application of SEQUEST sequencing software have allowed identification of two related peptides, a hexapeptide and a nonapeptide, formed from vicilin, one of the cocoa storage proteins. Time course studies of the two peptides show different abundance profiles and indicate, in part, production of the hexapeptide from the nonapeptide.     

Voyager 2 in the uranian system: imaging science results

Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70 degrees to -27 degrees ), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20 degrees . Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10(2) new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main rings system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the e ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About halfof Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition.