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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2010

Abstract

The fruit quality of European blueberry (EB) is mainly determined by taste compounds (sugars, acids, flavour) and health-beneficial structures generally denoted as antioxidants (vitamin C, phenolic acids, flavonols, anthocyanins, proanthocyanidins). Content and compound composition is strongly affected by the growth environment regarding light, temperature, water and edaphic factors. In order to assess genotypic relationships (northern and southern clones of EB) and environmental impact (temperature, day length) on berry quality parameters, a high-throughput system for blueberry metabolite profiling of nutritional compounds was established based on gas chromatography coupled with mass spectrometry (GC/MS). Dried methanol/H2O extracts from fresh-frozen berry tissue were derivatized, and subjected to GC/MS in order to detect polar compounds such as organic acids from Krebs-cycle, amino acids, sugars, polyols, and partly secondary metabolites (phenols, flavonoids). In addition, general quality parameters such as total phenols, total anthocyanins and antioxidant capacity (FRAP) were measured. Fructose (5 g), glucose (5 g), and sucrose (0.5 g/ 100 g f.w. at average) were the most abundant carbohydrates, together with high levels of organic acids such as citric acid (1.3 g), quinic acid (1.6 g), and malic acid (0.3 g/ 100 g f.w. at average). More than 50 metabolites per sample (identified compounds and not-annotated mass spectral tags) could be detected, and established the basis for multivariate statistics using principal component analysis, hierarchical clustering, and metabolite network analysis. Genotypic differences, modulation of metabolite pools and biosynthetic relationships are being discussed in-depth.

Abstract

Two female and two male cultivars have previously been released as a result of clone evaluation at Bioforsk Nord Holt. Selection criteria have been number of pistils or stamens per flower, number of flowers and number of shoots per m2. Currently a new group of clones are evaluated with the aim of finding new cultivars for release. The clones are collected from different parts of Norway, as well as from England and Spitsbergen. Preliminary results from harvesting 2005, 2006, 2007 and 2008 indicate good production potential for a couple of the tested clones. In addition to prior selection criteria based on berry yield, the levels of total anthocyanins and total phenols have been analyzed. This includes studies on the role of female clone, male pollinator and temperature on berry quality.

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Abstract

In this study we investigated the interaction between temperature and genotype on fruit development and levels of total phenols and anthocyanins in cloudberry. The experiment was done in a phytotron using one female (‘Fjellgull") and one hermaphroditic (‘Nyby") cultivar. Plants were grown at 9, 12, 15 and 18°C in 24-h photoperiod. The female cultivars were pollinated with pollen from a male (‘Apollen") clone and from the hermaphrodite clone. Parthenocarpic fruit development was induced by gibberellic acid (GA3). Ripe berries were frozen individually at -80°C and stored until analyses. There was a linear, double logarithmic relationship between temperature and number of days from pollination/GA3-treatment to ripening. ‘Fjellgull" had significantly larger berries than ‘Nyby", and the largest berries were obtained at 12 and 9°C. Pollen clone did not have a significant effect on berry size. GA3 induced parthenogenesis in ‘Fjellgull" and partial parthenogenesis in ‘Nyby". In ‘Fjellgull", the parthenocarpic berries were comparable to pollinated ones at low temperatures, but at 18°C their development was restricted. The level of total anthocyanins was significantly higher in ‘Fjellgull" than in ‘Nyby", and these levels were significantly enhanced at 9 and 12°C compared to higher temperatures. Levels of total phenolic compounds were not significantly affected. In conclusion, the present results indicate that low temperature is favourable both for size and quality of cloudberries.

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Abstract

Earliness, fruit yield and quality of six annual-fruiting raspberry (Rubus idaeus L.) cultivars were tested under protected cultivation in a cool Nordic environment. After raising plants for 5 weeks in greenhouses with average mean temperatures of 20 degrees C, 22 degrees C, or 26 degrees C, the plants were cropped in an open plastic tunnel at latitude 61 degrees N. The highest yielding cultivars were 'Autumn Bliss' and 'Polka', with 640 g plant(-1). Overall, the most promising cultivar was 'Polka' which combined high yield with large fruit of good flavour and firmness. In earliness, 'Polka' was surpassed only by 'Autumn Bliss', which confirmed its position as the earliest commercial annual-fruiting cultivar. However, 'Autumn Bliss' had soft fruits with little flavour and a short shelf-life, which greatly reduced the potential of the cultivar for the fresh fruit market. The later ripening cultivar 'Erika' did not complete its crop under these conditions, but its large unrealised yield potential and good fruit quality rendered it extremely promising for environments with a longer growing season. 'Sugana' was late, with low yields and poor fruit quality, while 'Marcela' did not yield enough fruit to be of interest under the present conditions. High temperatures during the 5-week raising period generally advanced flowering and fruit ripening in all cultivars, with the notable exception of 'Autumn Treasure' in which flowering was suppressed and strongly delayed by high temperature. Under the present conditions, there was a highly positive correlation between earliness and fruit yield. Regression analyses identified a low number of dormant buds as the single most important component of plant architecture associated with high fruit yield, accounting for 47% of the total variation.

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Abstract

The effects of postflowering temperature on the fruit chemical composition of Glen Ample raspberries were studied under controlled environment conditions. The berry weight decreased significantly with increasing temperature (12, 18, and 24 degrees C) and with progress of the harvest period. Because the moisture content increased in parallel with the berry weight, the antioxidant capacity (AOC) and the concentration of a range of bioactive compounds decreased with decreasing temperature and progress of the harvest season when expressed on a fresh weight basis in the conventional way. Under those circumstances, dry weight units are therefore preferable. However, despite the dilution effect of large berries, the concentration of ascorbic acid (vitamin C) increased with decreasing temperature, even on a fresh weight basis. Berry AOC was closely correlated with total phenolic concentration (r = 0.958), predominantly anthocyanins and ellagitannins. While a total of 10 anthocyanins were detected, cyanidin-3-sophoroside and cyanidin-3-(2(G)-glucosylrutinoside)-rutinoside accounted for 73% of the total, the former decreasing and the latter increasing with increasing growth temperature. By far, the most prevalent ellagitannins were lambertianin C and sanguiin H-6, both of which increased significantly with increasing temperature. It is concluded that the growth temperature has significant and contrasting effects on the concentration of a range of potentially bioactive compounds in raspberry.

Abstract

Red raspberry (Rubus idaeus L.) is an economically important small fruit species, rich in antioxidants and other phytochemicals (Rao and Snyder, 2010). Most research in the area of screening the antioxidant activity in dietary plants have mainly been focused on variation among species and cultivars and effects of postharvest handling and storage (e.g. Kalt et al., 2002). Little is known about the impact of environmental factors such as temperature and light conditions. The use of plastic tunnels for out-of-season production of red raspberries has expanded production in Norway. This involves a change in climate environment which might influence the chemical composition of the fruits. Here we present the results of an investigation of temperature on fruit quality of red raspberry (Remberg et al., 2010).