| 1. |
- Hvitt Strömvall, Ann-Margret, 1963, et al.
(författare)
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Conifer monoterpenes emitted to air by logging operations
- 1991
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Ingår i: Scandinavian journal of forest research. ; 6, s. 253-258
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Tidskriftsartikel (refereegranskat)abstract
- Concentration levels in air were determined for monoterpenes emitted from forestry operations in south-west Sweden. Field samples were collected on Tenax cartridges and analyzed in the laboratory by techniques based on gas chromatography. Processing of Scots pine as well as Norway spruce with a harvestor gave rise to about 1000 microgram/m3 of total monoterpenes near the machine. The corresponding levels above fresh branch wood were 100-500 microgram/m3. The background level was around 1 microgram/m3. The major monoterpenes were alpha-pinene and 3-carene from Pinus sylvestris and alpha-pinene and beta-pinene from Picea abies. Compounds constituting 1-10 % each of the total monoterpenes were camphene, 3-carene, limonene, beta-phellandrene and myrcene for spruce and camphene, beta-pinene, limonene, beta-phellandrene, myrcene and terpinolene for pine. Representative percent compositions for the two species are given for 13 monoterpenes. Photo-oxidant formation from the monoterpenes is discussed with respect to potential local contributions to strain and damage of the forests. Possible preventive measures are suggested.
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| 2. |
- Hjerdin, A, et al.
(författare)
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Genetic Variation Among Wild and Cultivated Beets of the Section Beta as Revealed by RFLP Analysis
- 1994
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Ingår i: Journal of sugarbeet research. - 0899-1502. ; 31:1&2, s. 59-67
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Tidskriftsartikel (refereegranskat)abstract
- The level of genetic variation detected among 7 sugar beet and 4 fodder beet breeding lines was compared to the variation found among 21 accessions of wild beets of the section Beta. RFLP analysis used a set of 32 sugar beet DNA sequences as probes to score a total of 351 bands over all accessions. The band data was used to calculate genetic distances between all pairs of accessions. The distance estimates were subsequently used in a cluster analysis to produce a dendrogram of genetic distances. The analysis unambiguously defined all accessions and clearly defined a fodder beet cluster within the sugar beet cluster. The cultivated beets were all separated from the wild beets. The sugar beet breeding lines showed a considerable amount of genetic variation, comparable with the level of variation detected among the wild beet accessions.
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| 3. |
- Börjesson, Thomas S., et al.
(författare)
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Off-odorous compounds produced by molds on oatmeal agar : Identification and relation to other growth characteristics
- 1993
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Ingår i: Journal of Agricultural and Food Chemistry. - Washington : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 41:11, s. 2104-2111
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Tidskriftsartikel (refereegranskat)abstract
- Ten Penicillium and Aspergillus species, four with a strong musty off-odor and six reference fungi without any characteristic odor, were cultivated on oatmeal agar for 5 days in cultivation vessels provided with an inlet and an outlet for air. Samples of volatile metabolites were collected on a porous polymer adsorbent attached to the outlet from day 2 through day 5 after inoculation. Adsorbed compounds were desorbed thermally and analyzed with GC/MS and a combined GC and sensory analysis, the GC sniff technique. Multivariate analysis of GC/MS and fungal odor data revealed strong associations between 6 of 65 volatile compounds and musty off-odor. The GC sniff technique showed that five of these, dimethyl disulfide, 1-octen-3-ol, 2-methylisoborneol, and two C11H18 compounds, had prominent off-odors. In addition, geosmin, 1-methoxy-3-methylbenzene, and methylphenol were produced in large amounts by some off-odorous fungi and contributed to their unpleasant odor. 3-Methylfuran, 2-methyl-1-propanol, and 3-methyl-1-butanol were much more commonly produced than the off-odorous compounds. Both odorous and other volatile metabolites could be detected after 2 days of fungal growth. The production of odorous metabolites was enhanced at the time of sporulation.
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| 4. |
- Petersson, Stina, et al.
(författare)
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Growth of Penicillium roqueforti, P-carneum, and P-paneum during malfunctioning airtight storage of high-moisture grain cultivars
- 1999
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 17:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- Penicillium roqueforti is an important spoilage fungus in high-moisture grain stored under airtight conditions where a malfunctioning storage system allows air leakage. It has recently been proposed that P. roqueforti be divided into three different species: P. roqueforti, P. carneum, and P. paneum (Boysen, M., Skouboe, P., Frisvad, J., Rossen, L., 1996. Reclassification of the Penicillium roqueforti group into three species on the basis of molecular genetic and biochemical profiles. Microbiology 142, 541-549). Differences in susceptibility to infection with the three mold species among winter wheat, spring wheat, rye, and barley during airtight storage of high-moisture grain were evaluated using a variety of grain cultivars. To simulate air leakage into such a storage system, grain (0.96 water activity) was inoculated, packed in glass tubes with a restricted air supply and incubated at 25 degrees C for 14 days. Molds and yeasts were quantified as colony forming units (CFU) on selective media. Generally, there was no difference in infection ability between P. roqueforti, P. carneum and P. paneum. All of them reached about 10(6) CFU/g in barley and winter wheat. However, rye appeared to be resistant to infection. A comparison of different barley and spring wheat cultivars revealed that P. roqueforti, P. carneum and P. paneum grew less vigorously on the malt cultivars Maud and Mentor and the spring wheat cv. Dragon than on other cultivars. In addition, batch-related differences in resistance to mold growth were found for spring wheat cv. Dragon.
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| 5. |
- Petersson, Stina, et al.
(författare)
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Pichia anomala as a biocontrol agent during storage of high-moisture feed grain under airtight conditions
- 1999
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Ingår i: Postharvest biology and technology. - : Elsevier. - 0925-5214 .- 1873-2356. ; 15:2, s. 175-184
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Tidskriftsartikel (refereegranskat)abstract
- Pichia anomala is antagonistic against a range of spoilage molds in vitro as well as against Penicillium roqueforti in high-moisture wheat during malfunctioning airtight storage in laboratory experiments. The use of Pichia anomala to improve the postharvest control of Penicillium roqueforti during airtight storage of feed grain was evaluated in outdoor silos. Inoculated and control winter wheat (cultivar Kosack) in 160-kg portions were stored at a water activity of 0.93 for 12 months in silos that were opened twice a week. During the first 2 months, inoculated Pichia anomala increased to about 10(7) colony-forming units (CFU)/g, while naturally occurring Pichia anomala in the treatments without inoculated yeast increased from 10(4) to 10(6) CFU/g. During the same period, CO2 concentrations increased to almost 70% and stabilized at 50-60%. During the coldest period, O-2 concentrations of <1% could be detected between samplings, whereas during the rest of the storage detectable O-2 levels were only found immediately after sampling. There were no clear differences in CO2 or O-2 levels between treatments. The inoculated Penicillium roqueforti did not grow during the storage period, probably owing to high numbers of Pichia anomala in combination with the high CO2 and low O-2 concentrations in the silos. In laboratory experiments, it was found that Pichia anomala survived long-term storage in airtight sealed test tubes better at 15 degrees C than at - 20 degrees C. The aerobic stability of moist wheat after 10 and 12 months of silo storage was clearly enhanced by an initial inoculation with Pichia anomala.
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| 6. |
- Schnürer, Johan, 1957-, et al.
(författare)
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Ergosterol Levels and Mould Colony Forming Units in Swedish Grains of Food and Feed Grade
- 1992
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Ingår i: Acta Agriculturae Scandinavica - Section B. - Oslo, Norway : Scandinavian University Press. - 0906-4710 .- 1651-1913. ; 42:4, s. 240-245
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Tidskriftsartikel (refereegranskat)abstract
- Although ergosterol is considered to be a suitable indicator of mould growth in cereal grains, there are few reference values available for Scandinavian conditions. We have determined the ergosterol levels in Swedish grain of different origins: cleaned food-grade wheat from a commercial mill, feed-grade cereals (oats and barley) with different odours and cereals (winter wheat, ''American wheat'', triticale and rye) from various field trials conducted in south-central Sweden in 1990. Specific objectives were to elucidate the relationships between ergosterol levels and numbers of mould colony forming units (CFU) and between ergosterol and grain odour.Ergosterol levels in the food-grade wheat ranged between 2.4 and 2.8 mug/g DW, and between 3.0 and 5.6 mug/g DW in the field trial cereals, while values in most of the feed grain samples ranged from 8-15 mug/g DW The levels agree with other published data for European grains.A positive correlation was found between numbers of colony-forming units and ergosterol concentration. The degree of correlation was higher when numbers of CFU were determined on dichloran-glycerol 18% agar with a low water activity (aw = 0.95) than on malt extract agar (aw = 0.99). There was no agreement between ergosterol levels and grain odour, since even samples described as having a fresh smell had high ergosterol levels. However, the highest level (33 mug/g DW) was found in a sample with a pronounced musty odour, and the lowest (1.1 gg/g DW) in a sample that smelled as if it had been heat damaged.
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| 7. |
- Gadd, Carl-Johan, 1948
(författare)
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Jordbruksomvandlingen på 1700-talet
- 1996
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Ingår i: Mellan bronssköld och Jas-plan - glimtar av Lidköpingsbygdens historia. Red. E. Holmström.. - Lidköping : Lidköpings kommun. - 9188048101
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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