Publikasjoner
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2024
Forfattere
Martin Næsset HillestadSammendrag
Large volumes of Norway spruce (Picea abies (L.) Karst.) in Northern Norway are approaching maturity. Previous studies conducted on Norway spruce from Northern Norway, indicates lower density and mechanical properties than for Norway spruce grown in the rest of the country. This might be critical for use of Norway spruce from Northern Norway as structural timber. The purpose of this study was to assess lumber quality, density, modulus of elasticity and modulus of rupture on a sample of Norway spruce from Northern Norway, and to evaluate whether visual strength grading results in sufficient properties. Density and mechanical properties were compared to values from Southern Norway, and previous studies from Northern Norway. A sample consisting of 109 boards sawn from 12 trees of Norway spruce, collected from 4 trial stands in Northern Norway, was visually strength graded according to NS-INSTA 142, before density, modulus of elasticity and modulus of rupture was tested according to NS-EN 408. Characteristic values calculated according to NS-EN 384 and verified according to NS-EN 14358, were compared to the strength classes of NS-EN 338. Variation in density and mechanical properties were modelled with linear mixed models, where the random variance was separated into tree-variance and residual variance. Variables on board and log level were treated as fixed effects, and used as covariates in the models. Relative height, calculated as each log’s vertical position in relation to total tree height, was the most important variable for density. Density increased with increasing relative height. Density was important for modulus of elasticity and modulus of rupture, and both increased with increasing density. Variation in density between stands seems to be partly attributed to variation in latitude and altitude. Knots affected both modulus of elasticity and modulus of rupture, and differences in average knot diameter seems to coincide with differences in mechanical properties between stands. Differences in average knot diameter and mechanical properties between stands coincides with differences in silviculture. Mean values for density, modulus of elasticity and modulus of rupture were lower than what is observed in the Southern and middle parts of Norway, but higher than previous studies from Northern Norway. The visual grading resulted in most boards sorted as grade T2, followed by T1, T3 and T0. The characteristic values met requirements for all sorting grades apart from density in T3 for C30, and modulus of rupture in T1 for C18. Low numbers resulted in large uncertainties concerning characteristic values. Despite this, sorting grades T2 and T2+T3 met all requirements for C24. The results give positive indications for density, modulus of elasticity and modulus of rupture in Norway spruce from Northern Norway, and the properties as structural timber. The study is based on a limited sample of boards, collected from a limited number of trial stands, and this results in large uncertainties. Further studies are therefore needed, and should gain values more representative for the forest in Northern Norway.
Sammendrag
In Norway, there is political goal to increase the degree of self-sufficiency of fruits. To achieve this goal, the sales period of Norwegian produced apple fruit needs to be extended, and thus, the storage technology improved. Sensory quality is of importance for consumers acceptability of the apple fruit. The aim of this study was to evaluate the sensory properties of the apple cultivars ‘Red Elstar’ and ‘Rubinstep’ treated with 1-methylcyclopropene (1-MCP) in combination with storage in regular and controlled atmosphere. Before storage, the harvested fruit were divided into two parts; half treated with 1-MCP and the other half untreated. A semi-trained sensory panel evaluated selected sensory properties of apple fruit harvested in 2021, 2022, and 2023, and stored in regular or controlled atmosphere at 2°C for 5.5, 5.5, and 4 months, respectively. Treatment with 1-MCP in combination with controlled atmosphere storage resulted in the highest sensory score of firmness, crispiness, and juiciness, and lowest score for mealiness and sweetness. Fruit stored in a regular atmosphere without 1-MCP had less acidity and the fruitiest aroma. How to obtain optimal taste of ‘Rubinstep’ and ‘Red Elstar’ after the different post-harvest treatments will be discussed.
Sammendrag
In Norway, the apple cultivar ‘Red Aroma’ accounts for approximately one third of the Norwegian production. Treatment with 1-MCP has been tested on fruit of different ripening degrees to improve shelf-life and sensory properties. Fruits were harvested and treated with 1-MCP at one-week intervals starting two weeks before optimal harvest time (OHT) and ending two weeks after OHT. Fruits were stored until the end of November in regular atmosphere at 4 °C. A semi-trained sensory panel evaluated selected sensory parameters in addition to measurements of physiochemical parameters using traditional methods. The panel evaluated 1-MCP treated fruit from all harvest times as more acidic, firmer, less mealy, crisper, and juicier than the untreated fruit. The untreated fruit harvested one or two weeks after OHT were more aromatic (floral and fruity aroma), sweeter, and riper. Intensity of grassy flavour was lowest for the untreated fruit after the optimal harvest time. Some of the evaluated sensory properties correlated with measured physiochemical parameters. Optimal sensory quality in relation to harvest time and 1-MCP treatment will be discussed.
Sammendrag
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Forfattere
Synneva GjellandSammendrag
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Forfattere
Helge BerglannSammendrag
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Forfattere
Theresa Weigl Jorunn Børve Emily Follett Melissa Magerøy Carl Gunnar Fossdal Hanne Larsen Siv Fagertun RembergSammendrag
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Forfattere
Geir-Harald StrandSammendrag
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Sammendrag
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Forfattere
Anne MuolaSammendrag
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