Randi Seljåsen

Stasjonsleder / Forsker

(+47) 406 22 915
randi.seljaasen@nibio.no

Sted
Landvik

Besøksadresse
Reddalsveien 215, 4886 Grimstad

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Biosynthesis of phytochemicals in leaves of Brassica can be initiated by abiotic factors. The aim of the study was to investigate elicitor treatments to add value to waste of cabbage. A leaf waste fraction from industrial trimming of head cabbage was exposed to UV radiation (250–400 nm, 59 and 99 kJ∙m−2, respectively), photosynthetic active radiation (PAR, 400–700 nm, 497 kJ∙m−2), and ultrasound in water bath (35 kHz, at 15, 30 and 61 kJ∙l−1 water), in order to improve nutraceutical concentration. UV was more effective than PAR to increase the level of flavonols (2 to 3-fold higher) and hydroxycinnamate monosaccharides (1 to 10-fold higher). PAR was three times as effective as UV to increase anthocyanins. Interaction of PAR + UV increased antioxidant activity (30%), the content of five phenolics (1.4 to 10-fold higher), and hydroxycinnamic monosaccharides (compared with PAR or UV alone). Indoles were reduced (40–52%) by UV, but the other glucosinolates (GLS) were unaffected. Ultrasound did not influence any parameters. The results are important for white cabbage by-products by demonstrating that UV + PAR can be successfully used as an effectual tool to increase important phenolics and antioxidant activity of waste fraction leaves without an adverse effect on the main GLS.

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Mechanistic models are useful tools for understanding and taking account of the complex, dynamic processes such as carbon (C) and nitrogen (N) turnover in soil and crop growth. In this study, the EU-Rotate_N model was first calibrated with measured C and N mineralization from nine potential fertilizer resources decomposing at controlled soil temperature and moisture. The materials included seaweeds, wastes from the food industry, food waste anaerobically digested for biogas production, and animal manure. Then the model’s ability to predict soil and crop data in a field trial with broccoli and potato was evaluated. Except for seaweed, up to 68% of added C and 54–86% of added N was mineralized within 60 days under controlled conditions. The organic resources fell into three groups: seaweed, high-N industrial wastes, and materials with high initial content of mineral N. EU-Rotate_N was successfully calibrated for the materials of industrial origin, whereas seaweeds, anaerobically digested food waste and sheep manure were challenging. The model satisfactorily predicted dry matter (DM) and N contents (root mean square; RMSE: 0.11–0.32) of the above-ground part of broccoli fertilized with anaerobically digested food waste, shrimp shell pellets, sheep manure and mineral fertilizers but not algal meal. After adjusting critical %N for optimum growth, potato DM and N contents were also predicted quite well (RMSE: 0.08–0.44). In conclusion, the model can be used as a learning and decision support tool when using organic materials as N fertilizer, preferably in combination with other models and information from the literature.

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The aim of this study was to demonstrate how aquacultural sludge can be processed and utilized as an organic nutrient solution (ONS) for hydroponic lettuce production. By using a previous developed method, approximately 80% of the processed sludge was reclaimed as a clear, nutrient-rich solution. The performance of the recovered nutrient solution on lettuce growth was assessed in a nutrient film hydroponic system. The results were compared to the results obtained using a conventional nutrient solution (CNS). Yield, fresh weight, water consumption, and nutrient and heavy metal content in leaf tissue were measured. In spite of a 16% lower average fresh weight obtained in ONS compared to the weight obtained in CNS, there was no statistical difference of the yield of lettuce among the two nutrient solutions. After the cultivation period, 90% of the lettuce heads grown in ONS exceeded the marked weight of 150 g. Foliar analysis revealed a similar or higher content of all nutrients, except of magnesium and molybdenum in the leaves of lettuce grown in the ONS compared to lettuce grown in the CNS. This study shows that nutrients recovered from aquacultural sludge can be utilized as fertilizer, thereby reducing the dependency on mineral fertilizer in hydroponic and aquaponic systems.

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In this study, the nutrient dynamic and growth performance of lettuce in a closed recirculating hydroponic system were investigated. Lettuce was grown in three parallel nutrient film technique (NFT) units, illuminated with LED-light. A balanced standard nutrient solution (NS) was used, and the electrical conductivity (EC) and pH were adjusted regularly to constant average values of 1.16 mS cm‑1 and 6.2 with standard deviations of ±0.12 and ±0.5, respectively. The volume of NS in each unit was kept at 20 L by adding refill solution to replace nutrient uptake and transpiration. Lettuce growth during the first six weeks in the NFT-system was normal and stable. After six weeks, a decrease in concentrations of N, P, and K was observed, with a corresponding decline in yield of lettuce. After ten weeks, lettuce weight at harvest was reduced by 56% in average compared to the control, and the concentrations of N, P and K in the NS were reduced by 54.5, 90.5 and 96.6%, respectively. Contrarily, more slowly absorbed nutrients like Ca, S, Zn, Cu, and B experienced increases by factors of 2.2, 2.9, 6.6, 4.9 and 2.5, respectively. The depletion and accumulation of nutrients in the NS were reflected in corresponding deficiency and excess levels of nutrients in leaf tissue compared to norm-values of healthy lettuce. The study showed that after six weeks, corresponding to a yield of 1 kg lettuce per 10 L tank volume of NS, the reduced growth implied that the recirculated NS should have been discharged and replaced, or a “tailor-made” refill solution should have been used to avoid depletion of some nutrients. Based on the foliar analysis and calculations of actual nutrient absorption rates, the composition of such a refill NS was suggested.

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Orientering om prosjektet "Nye arter for kornområdene", muligheter og utfordringer ved å ta inn nye proteinrike arter i vekstskifte med korn, og situasjonen for produksjonen av planteprotein i Norge i dag. Visning av forsøksfelt med quinoa, bokhvete, linser, kikerter, søtlupin og soya.

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Denne rapporten er en litteratursammenstilling som tar for seg effekter av ulike tiltak på avrenning av næringsstoffene fosfor og nitrogen, og partikler fra områder med potet- og grønnsaksdyrking. I Norge utgjør områdene med potet- og grønnsaksdyrking en forholdsvis liten del av det totale jordbruksarealet, men representerer allikevel lokalt en viktig kilde til vannforurensning ettersom utvasking og avrenningen av næringsstoffer, særlig fosfor, og jordtapene er mye større fra grøntproduksjon enn fra for eksempel korndyrking og eng/beiteområder. Kunnskap om dyrkingssystemenes effekt på avrenningsprosesser er viktig for å oppnå kostnadseffektiv potet- og grønnsaksproduksjon med minst mulig negativ effekt på miljøet. Sammenstillingen inkluderer en vurdering av fordeler og ulemper ved de ulike tiltakene under norske forhold, samt hvor stor nytte de har sammenliknet med kostnaden av tiltaket.

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The project “Sustainable food production through quality optimized raw-material production and processing technologies for premium quality vegetable products and generated by-products” [SUNNIVA] aimed at the development of a sustainable food system from production to consumption, addressing the entire food supply chain for the vegetables tomato and Brassicae. The goal was better utilisation of the vegetable raw materials, reduced energy and water consumption, higher profitability and healthier food. This was achieved by providing various valorisation strategies to reduce waste and limiting environmental impact. Preservation of the intrinsic health-beneficial phytochemicals present in the raw material in order to improve the nutritional properties of vegetable food products was central in the project. The project contained optimization of harvest time and pre-processing storage conditions, development of novel mild processing design based on modelling, and a two-track valorisation strategy. SUNNIVA has demonstrated how the various residual raw materials can be exploited to the full: Either directly for sustainable production of healthy food (as a refined product or an ingredient), or indirectly by bringing it back into the food chain (as organic fertilizers and soil amendment products) in order to generate renewed primary production with minimal environmental impact.

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A circular bioeconomy has become a global aspiration for governments in Europe and around the globe. This article pursues research questions concerning concrete innovations aiming to create bioeconomic transition options in Norway and presents results from a transdisciplinary investigation of Norwegian food industry cases involving processing of fish, meat, fruit, and vegetable co-streams aiming to capture or even increase use and value of residues from processing. It shows that while objectives of avoiding food losses and transforming co-streams to new products of higher value characterizes the poultry industry case and part of the ‘blue’ sector, challenges remain particularly in the ‘whitefish’ area where - also at the global level - a high share of fish resources ends as rest raw materials, i.e. not fully utilised. The investigation targeted strategic cases of innovations enabling alternative uses of co-streams: automation and scanning technologies for fractioning raw materials and co-streams into different qualities, a collection system for fish rest raw materials at sea, enzymatic hydrolysis, use of second grade vegetables for smoothies and potato peels for biodegradable plastics in the vegetable (potato) processing industries. The article shows how these innovations enable cascading and valorisation of co-streams and why an upcycling potential exists as well. Its main contribution is in demonstrating feasibility of transdisciplinary research and innovative options for bioeconomic transition towards sustainability.

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Matching high performing varieties of legumes with effective symbiotic N-fixing bacteria can potentially enhance production volumes and economic returns when cultivating grain legumes. We investigated whether field inoculation with local or introduced Rhizobia to six different varieties of faba bean improved growth, nitrogen (N) fixation and protein content in a field experiment in Southern Norway. In 2016, a full factorial experiment featuring three inoculation treatments (a mixture of four morphotypes of Rhizobia isolated from locally grown faba bean, a mix of two efficient and well documented Rhizobium strains from Latvia, and a non-inoculated control treatment) and six faba bean (Vicia faba) genotypes (Agua Dulce, Bauska, Jõgeva, Gloria, Julia, Lielplatones) was set up in an experimental field with sandy loam soil with no recent legume culture history (>10 years). At late flowering/early pod formation stage we quantified N fixation of the crop using the N-15 natural abundance method, using weeds from the same plots as reference plants. We also assessed morphological and phenological characters, seed yields and protein levels at plant maturity. Clear differences were observed, and detailed results from this study will be presented at the conference (analyses are still pending). This research is a part of the EU FP7 project Eurolegume.

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BACKGROUND Broccoli (Brassica oleracea L. var. italica) is a popular vegetable grown at a wide range of latitudes. Plants were grown in 2009–2011 in pots with standardized soil, irrigation and nutrient supply under natural temperature and light conditions at four locations (42–70° N). A descriptive sensory analysis of broccoli florets was performed by a trained panel to examine any differences along the latitudinal gradient for 30 attributes within appearance, odour, taste/flavour and texture. RESULTS Average results over three summer seasons in Germany, southern Norway and northern Norway showed that the northernmost location with low temperatures and long days had highest scores for bud coarseness and uniform colour, while broccoli from the German location, with high temperatures and shorter days, had highest intensity of colour hue, whiteness, bitter taste, cabbage flavour, stale flavour and watery flavour. Results from two autumn seasons at the fourth location (42° N, Spain), with low temperatures and short days, tended toward results from the two northernmost locations, with an exception for most texture attributes. CONCLUSION Results clearly demonstrate that temperature and light conditions related to latitude and season affect the sensory quality of broccoli florets. Results may be used in marketing special quality regional or seasonal products. © 2016 Society of Chemical Industry

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More sustainable production of high-quality, nutritious food is of worldwide interest. Increasing nutrient recycling into food systems is a step in this direction. The objective of the present study was to determine nitrogen (N) fertiliser effects of four waste-derived and organic materials in a cropping sequence of broccoli, potato and lettuce grown at two latitudes (58° and 67° N) in Norway during three years. Effects of anaerobically digested food waste (AD), shrimp shell (SS), algae meal (AM) and sheep manure (SM) at different N application rates (80 and 170 kg N ha–1 for broccoli, and 80 and 60 kg N ha–1 for potato and lettuce, respectively) and residual effects were tested on crop yield, N uptake, N recovery efficiency (NRE), N balance, N content in produce, mineral N in soil, product quality parameters and content of nitrate in lettuce. Mineral fertiliser (MF) served as control. Effects on yield, N uptake, NRE, N balance and product quality parameters could to a great extent be explained by estimated potentially plant-available N, which ranked in the order of AD>SS>SM>AM. Results for crops fertilised with AD and SS were not significantly different from MF at the same N application rate, while AM, in agreement with its negative effect on N mineralisation, gave negative or near-neutral effects compared to the control. No residual effect was detected after the year of application. The results showed that knowledge about N dynamics of relevant organic waste-derived fertilisers is necessary to decide on the timing and rate of application.

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Quality traits are highly focused upon in the marketing of organic food products. There is a need to define and measure quality as consumers seem to have preconceived notions about the superior health value and taste of organic compared to non-organic products. A commonly held opinion among many consumer groups is that organic farming guarantees optimum quality, despite the fact that this remains unproven. The aim of this paper is to contribute to a better understanding of the complexity of quality traits in a plant-based food product, using carrots as an example. Selected designated quality aspects are presented to describe the complexity of quality and discuss the challenges of using these aspects in differentiating between organic and conventional products. The paper concludes we have insufficient tools to be able to adequately authenticate organically produced carrots. The same may be the case for most vegetables and fruit products. Suggestions for further studies include the soil and location aspect (terroir), in order to trace a product back to its origin in an organically or conventionally farmed field by finding a unique fingerprint for chemical constituents of samples.

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Aim: The objective was to assess the nitrogen provided to following crops by peas and fava beans, with varying legume residue incorporation and use of cover crops. Meth: Organic field trial, ‘spilt-split plot design’ with 4 blocks. Whole plots (spring 2014) had legumes (pea or faba beans), and sub plots (autumn 2014) had 4 autumn soil treatments with combinations of legume residue incorporation and cover crop. The sub-sub plots (spring 2015) were with and without additional manure fertilization. Res: The root biomass of both legume pre cops had equal nitrogen (N) concentration, but total root biomass was twice as high for fava beans as for peas (5.08 vs. 2.41 kg m-2). Fava bean pre crop with biomass incorporation without cover crop gave the highest broccoli yield (4.10 t ha-1) compared with pea pre crop with biomass incorporation and no cover crop (2.44 t ha -1). Also the last crop in the rotation, lettuce, had 94% higher yield after fava beans (6.6 t ha-1) compared to peas (3.4 t ha-1). Rye as cover crop efficiently assimilated and conserved N during winter, shown by a 4 to 5 fold reduction in soil NO3-N, and nearly 2 fold reduction in soil N-min levels, compared to open soil. Additional manure application affected crop yield, with 3 and 2 fold increase in broccoli and lettuce respectively. Conc: Fava beans as pre crop resulted in higher yields of broccoli and lettuce the following seasons, compared to peas. This was explained twice as much root biomass for that crop.

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Organic vegetable production attempts to pursue multiple goals concerning influence on environment, production resources, and human health. In areas with limited availability of animal manure, there is a need for considering various off-farm nutrient resources for such production. Different organic and waste-derived fertilizer materials were used for broccoli production at two latitudes (58° and 67°) in Norway during two years. The fertilizer materials were applied at two rates of total N (80 and 170 kg ha–1) and compared with mineral fertilizer (170 kg ha–1) and no fertilizer. Broccoli yield was strongly influenced by fertilizer materials (algae meal < unfertilized control < sheep manure < extruded shrimp shell < anaerobically digested food waste < mineral fertilizer). Yield, but not glucosinolate content, was linearly correlated with estimated potentially plant-available N. However, extruded shrimp shell and mineral NPK fertilizer gave higher glucosinolate contents than sheep manure and no fertilizer. Sensory attributes were less affected by fertilizer material and plant-available N.

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The effect of different degrees of attack by carrot psyllid (Trioza apicalis) on quality parameters of carrots was studied in field experiments for two years. Treatments were different degrees of physical insect protection by floating row cover. An increasing attack level of psyllids showed an enhancement effect on the antioxidant capacity (ORAC), content of falcarindiol, 6-methoxymellein, and terpenes, and scores for bitter taste, chemical flavor, terpene flavor, and toughness. Carrot psyllid attack decreased the yield, total sugar, fructose, glucose, and sensory attributes sweet taste, color hue, color strength, crispiness, and juiciness. Carrot plants at 8−10 weeks of age tolerated attack by psyllids at low levels (2% leaves with curling or discoloration).

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In this review, we provide an overview of the role of glucosinolates and other phytochemical compounds present in the Brassicaceae in relation to plant protection and human health. Current knowledge of the factors that influence phytochemical content and profile in the Brassicaceae is also summarized and multi-factorial approaches are briefly discussed. Variation in agronomic conditions (plant species, cultivar, developmental stage, plant organ, plant competition, fertilization, pH), season, climatic factors, water availability, light (intensity, quality, duration) and CO2 are known to significantly affect content and profile of phytochemicals. Phytochemicals such as the glucosinolates and leaf surface waxes play an important role in interactions with pests and pathogens. Factors that affect production of phytochemicals are important when designing plant protection strategies that exploit these compounds to minimize crop damage caused by plant pests and pathogens. Brassicaceous plants are consumed increasingly for possible health benefits, for example, glucosinolate-derived effects on degenerative diseases such as cancer, cardiovascular and neurodegenerative diseases. Thus, factors influencing phytochemical content and profile in the production of brassicaceous plants are worth considering both for plant and human health. Even though it is known that factors that influence phytochemical content and profile may interact, studies of plant compounds were, until recently, restricted by methods allowing only a reductionistic approach. It is now possible to design multi-factorial experiments that simulate their combined effects. This will provide important information to ecologists, plant breeders and agronomists.

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Abstract Two field trials are reported on Jerusalem artichoke (Helianthus tuberosus L.). Firstly, twenty genetic variants were compared with respect to crop yield, morphology and content of sugars and FOS in order to find genotypes suitable for Norwegian production. The highest yield and highest number of tubers per plant was obtained in early flowering variants, e.g. the white variant ‘Tysnes" gave 1.72 kg tubers per plant (28.7 t haa-1). Such early variants had markedly lower portion of smooth tubers. Late variants gave the most preferable tuber shape, but the yield was only half of the most productive ones. Dry matter content (%DM) varied from 19.67 to 23.33. Only a weak correlation was found between dry matter content and total content of FOS (r = 0.255) in the tubers. The mean content of FOS including sucrose through all variants was found to be 11.6 g 100g-1 FW or 55.0 g 100g-1 DW by measurement of non-hydrolyzed plant. Average chain length of FOS in the tubers was found to be DP3.9. There was no difference in tuber FOS content between flowering and non flowering variants. A second trial investigated the above ground part of one flowering and two late or non flowering variants during the growing season. Highest biomass was found for the late or non flowering variants when harvested in September. Total dry matter at time of harvest were found to be 0.21, 0.55 and 0,44 kg plant-1 for the variants ‘Dagnoytral", ‘Elverum" and ‘Krogerup" respectively (5.4, 14.1 and 11.3 t haa-1). At time of harvest stalks of ‘Elverum" and ‘Krogerup" contained 1.25 and 0.77 % fructose (DM) and 3.40 and 1.91 % sucrose. The content of soluble carbohydrates was found to be highest in stalks in August (sucrose and FOS major compounds).

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I et stort, kontrollert forsøk ble det funnet at sort hadde størst betydning, deretter kom jordtype, mens nitrogen- og kaliumnivå hadde minst betydning for sensorisk kvalitet av ferske gulrøtter. Myrjord ga høyere intensitet av syrlig smak, søtsmak, saftighet og hvithet enn sandjord eller morene. Temperaturen var lavere i myrjord enn i de andre jordene.

Sammendrag

Gulrot og kålrot med riktig kvalitet                                                                - et samarbeidsprosjekt for å styrke konkurranseevnen i norsk produksjon Smak og kvalitet av gulrot og kålrot påvirkes av flere dyrkingsmessige faktorer som gjødsling, jordtype og angrep av insekter. For å forstå forbrukerens krav til gulrot og kålrot er det nødvendig å se bruken av disse i en bredere sosial sammenheng. Prosjektet "Gulrot og kålrot med riktig kvalitet" ble startet opp i 2004 med Dr. Steinar Dragland som prosjektleder. Prosjektet er avsluttet i 2008 og publiseringer fra prosjektet vil foreligge utover i 2009. Grønnsaksnæringen, forskningen og forsøksringene har samarbeidet om dette prosjektet, for å avklare hvilke dyrkningskrav gulrot og kålrot stiller for å gi en smak etter forbrukernes ønsker.  

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Fra 1. januar 2008 er ingen effektive skadedyrmidler godkjent for bruk mot kålfluer i Norge. Det har siden 2004 vært en stor innsats ved Bioforsk i samarbeid med Landbrukets forsøksringer og med næringen til å finne frem til metoder og midler som vil beskytte korsblomstrede vekster mot kålfluer. Det er spesielt to prosjekter som har støttet mye av dette arbeid, ett brukerstyrt fra kålrotdyrkerne og ett fra Forskningsfondet. Resultatene viser at både nye midler og andre bekjempelsesmetoder kan gi tilfredsstillende beskyttelse. Men det er mye arbeid som gjenstår før all den nye viten kan tas i bruk.

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Jordskokk er en gammel matplante som er i ferd med å få en ny renessanse. Plantens underjordiske hvite knoller minner om potetknoller, men er mer ujevne i formen og har en helt annen smak og konsistens både i frisk og bearbeidet form. Den karakteristiske og spennende smaken hos jordskokk har lenge vært ettertraktet av kokker på restauranter verden over. Knollene er rike på helsegunstige stoff av typen fruktfiber (fruktooligosakkarider) som blir viet stadig større oppmerksomhet både innenfor tarmhelse, diabetes, overvekt og hjerte kar sykdommer. Stoffene stimulerer også opptak av kalsium og syntese av B-vitaminer i tarmen. Det har i løpet av en tre års periode blitt arbeidet med dyrkningstekniske utfordringer ved økologisk produksjon av jordskokk innenfor et prosjekt finansiert av Statens Landbruksforvaltning. Parallelt med dette har det blitt arbeidet med ulike oppdrag for konservesindustrien for å utvikle bearbeidede produkter av jordskokk. I tilknytning til satsningen er det etablert en dyrkergruppe og en egen nettside med informasjon om jordskokk (www.jordskokk.no). I dette innlegget vil økologisk produksjon vektlegges og presenteres sammen med de mer generelle temaene ved produksjonen.

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Mye forskning har vært utført innenfor temaet gjødsling i grønnsaker og det er bred enighet om at nitrogen er en av de viktigste faktorene for vekst og avlingsnivå. Undersøkelser av nitrogenets effekter på fysiske, kjemiske og sensoriske variabler har likevel blitt viet mindre oppmerksomhet i årenes løp. I denne oversikten gis en kort presentasjon av nyeste forskningsresultater innenfor dette området.

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Bekjempelsesmidler som har vært brukt mot kålfluene i mange tiår vil nå forsvinne fra markedet. Dette har ført med seg en kjempeutfordring i å finne nye metoder og midler for denne bekjempelsen. Et prosjekt ble startet opp i 2004 ved Planteforsk (nå Bioforsk) og Landbrukets forsøksringer (LFR) for å utforske flere metoder, inkludert nye skadedyrmidler. I tillegg er det i 2005 startet et prosjekt som er eid av Norges Gartnerforbund som tar opp samme problematikk, men med fokus mot kålrotproduksjon.

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A commercial extract of neem (NeemAzal-T) and a simple extract of pulverised seeds extracted in warm water were tested against the cabbage pest Mamestra brassicae L. Oviposition was reduced to half the number of eggs per plant by the neem treatment. The number of eggs that hatched was not affected by the neem treatment, but development of these larvae was strongly inhibited and all larvae in the neem treatment died within two weeks without reaching 2nd instar. The concentration of the active ingredient azadirachtin-A (the azadirachtin component in NeemAzal-T) needed to protect plants from damage by 2nd instar larvae was 8 "g ml"1. The lethal doses for 2nd instar larvae were 6.2 and 17.2 "g ml"1 for LC50 and LC95, respectively. NeemAzal-T protected plants from damage for at least three weeks if applied before oviposition, or at least two weeks if applied against 2nd instar larvae. In these studies, neem inhibited oviposition, larval development and feeding, and greatly increased mortality.

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Flere stoffer medvirker til smaken i gulrot. Aromastoff (terpener) og sukker produseres i veksttiden og er med på å danne den karakteristiske gulrotsmaken. Sekundære stoffer som 6-methoxymellein og etanol gir bitter og emmen smak og dannes hovedsakelig under stressbetingelser i løpet av lagring og distribusjon. Gulrotsmaken er i sterk grad genetisk betinget både med tanke på danningen smaken i vekstperioden og når det gjelder evne til å motstå smaksendring som følge av ulike stressbetingelser under distribusjon. Gunstig sortsvalg med fokus på smak kan danne et godt grunnlag for dyrkerens resultat. Forsiktighet med nitrogen og kaliumtilførsel er også viktig for optimal smak i gulrøttene. En skånsom håndtering og kjølig lagring i perforerte plastposer i fravær av etylen vil være optimalt under distribusjon av gulrøttene. Samlagring med frukt må unngåes, også i forbrukernes kjøleskap, hvis man vil hindre utvikling av bittersmak.

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Jordskokk (Helianthus tuberosus L.) er en flerårig plante i kurvplantefamilien og en nær slektning av solsikke. Den dyrkes spesielt på grunn av sine rotknoller som har en frisk, nøttaktig og søt smak og kan spises både naturell, kokt, og stekt. Knollene utmerker seg ved et høyt innhold av karbohydraten inulin som har søtsmak, men går ufordøyd gjennom fordøyelsessystemet og dermed kan være lovende blant annet i kosthold for diabetikere. Inulinet har også svært god virkning på tarmhelse ved å favorisere de sunne bifido bakteriene og hemme patogene bakterier i tykktarmen. Stoffet øker også opptak av kalsium og andre mineraler og stimulere syntesen av B-vitaminer. Jordskokk er sammen med sikori den viktigste inulinkilden som benyttes i industriell sammenheng for utvinning av inulin. Denne spesielle grønnsaken er ennå ikke for salg i vanlig detaljhandel i Norge, og den dyrkes kun i mindre skala for lokalt salg. Det importeres imidlertid en del jordskokk til resteurantnæringen. Ved Planteforsks avdeling på Landvik i Grimstad finnes det en samling med 40 kloner av jordskokk som er samlet inn fra hele Norden i regi av Nordisk Genbank. Det er stor interesse for å undersøke dette materialet nærmere med tanke på innhold av inulin, avlingspotensial og smak for å finne frem til en sort med som egner seg for kommersiell dyrking her til lands. Det kan også være interessant å prøve flere utenlandske sorter under norske forhold. Ernæringsfysiologiske studier av jordskokk i tilknytning til helse vil være et viktig ledd i å øke kunnskapen om potensialet til denne spennende grønnsaken.

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Brokkoliproduksjonen har økt sterkt de siste fem årene her til lands. I dyrkningsperioden er brokkoli mindre problematisk enn blomkål når det gjelder fysiologiske kvalitetsfeil knyttet til klima. Brokkoli kan imidlertid være utsatt for hulrom i stengelen. Dette forekommer oftest ved sterk nitrogengjødsling og andre forhold som gir rask vekst. Brokkoli er rik på vitaminene A (karoten), C, K, E og folinsyre. Blant mineralene er det mest av jern, kalsium og kalium. Brokkoli inneholder også en lang rekke antioksidanter (karotenoider, flavonoider, klorofyll og glukosinolater) som motvirker kreft, hjerte-karsykdommer, infeksjoner og mange andre sykdommer. Innhold av antioksidanter varierer sterkt for ulike sorter av brokkoli. Flere former for stress (sterkt lys, tørke og saltholdig jord) kan stimulere plantene til økt produksjon av antioksidanter. Bevaring av en god kvalitet gjennom lagring og omsetning av brokkoli er krevende fordi brokkoli er et blomsterorgan i rask utvikling som lett blir overmoden og gulner. Vanligvis holder brokkoli seg godt i 4 uker ved 0-4 °C og opp mot 100 % relativ luftfuktighet. Holdbarheten av brokkoli kan forlenges til 8 uker ved kjølig lagring i kontrollert atmosfære med 0,5 % O2 og 0-10 % CO2 i N2.

Sammendrag

Gulrøtter høstet for hånd eller med maskin og utsatt for tilleggststress i form av risting i en transportsimulator ble analysert for smak, aroma og innhold av sukker, terpener, 6-methoxymellein og etanol. I tillegg ble etylenproduksjon og respirasjon målt. Gulrøtter som var stresset ved risting hadde høyere etylenproduksjon og respirasjon, høyere innhold av etanol, sukker og flere terpentyper. Dette var i samsvar med enn høyere sensorisk popengsum for smak og lukt av etanol, bittersmak, terpensmak, jordsmak, ettersmak, emmensmak og lavere poeng for syrlig smak og søtsmak etter analyse av profesjonelt smakspanel. Etanolinnhold var sterkt korrelert til etanolsmak og -lukt og til emmensmak. Av de fire sortene som ble testet viste sortene "Bolero", "Panter" og "Yucon" seg å være mest følsomme overfor mekanisk stress, mens "Napa" og "Newburg" var mest resistente. Håndhøstede gulrøtter var ikke signifikant forskjellige fra maskinhøstede med hensyn på kjemiske og sensoriske variabler. Prinsipal komponent analyse viste lite forskjeller i plasseringer for disse to behandlingene i score plottet. En digital gulrot kunne måle graden av meksnisk stress som gulrøttene ble utsatt for.

Sammendrag

Gulrøtter ble analysert for smak og lukt, og for innhold av terpener, 6-methoxymellein og sukker gjennom tre ukers laring ved 15°C in etylenholdig atmosfære (1µl /  l). Behandlingen medførte økning i 6-methoxymellin og omdanning av større mengder sukrose til fruktose sammenlignet med kontrollgulrøtter som var lagret i luft. Utfra analyser av profesjonelt smakspanel var dette  i samsvar med høyere sensorisk poengsum for bittersmak og terpensmak og lavere poeng for søtsmak. Prinsipal komponent analyse viste en sterkere uttrykt bittersmak, jordsmak, grønnsmak, terpensmak og ettersmak i de etylenbehandlede gulrøttene. Det ble funnet en korrelasjon mellom søtsmak og innhold av sukrose (r = 0.91, p < 0.005) og melom flere terpener (y-terpinen, limonen and karyofyllen) og terpen aroma, grønnsmak, ettersmak og bittersmak (r ³ 0.72, p < 0.05). For gulrøtter lagret i ren luft så det ut til at disse dårlige smakene ble maskert av et høyere sukroseinnhold.

Sammendrag

Ved modifikasjon av eksisterende metoder har vi utviklet en hurtig metode for kvantifisering av 6-methoxymellein i gulrot ved hjelp av ekstraksjon i kokende vann og fast fase ekstraksjon, etterfulgt av væslekromatografi (HPLC). Utbyttet i metoden ble funnet å være tilfredsstillende etter testing av tre etterfølgende ekstraksjoner i gulrotprøver med ulikt innhold av 6-methoxymellein. Gjenvinningen var 96-99% etter første ekstraksjon. Med denne metoden var det mulig for en person å ekstrahere 20 prøver i løpet av en arbeidsdag og videre kvantifisere innholdet av 6-methoxymellei ved automatisk HPLC den etterfølgende natt.

Sammendrag

Dette bokkapitlet er en oversikt over effekter av klorofyll, karotenoider og flavonoider i grønnsaker mot kreft, hjerte - kar sykdommer og virus. Det er funnet beskyttende effekt av et øket grønnsakkonsum på kreft i munn, svelg, spiserør, lunger, mage, tykktarm og endetarm. Disse stoffene har også vist seg å kunne bidra til en mulig senket risiko for hjerte-kar sykdommer. Vi kan konkludere med at det også ser ut til å være en beskyttende effekt av flavonoider mot flere virussykdommer. Gulrøtter, tomater, løk, og grønne grønnsaker som broccoli, grønnkål, persille, bladcelleri og spinat inneholder høyest nivå av disse beskyttende stoffene.

Sammendrag

A commercial extract of neem (NeemAzal-T) and a simple extract of pulverized seeds extracted in warm water were tested against the cabbage pest Mamestra brassicae L. Gravid cabbage moth females were given a choice between sprayed and unsprayed plants for oviposition during 9 days. Second instar larvae were caged on plants and exposed to a series of neem concentrations (leaf dip assay) and to neem applied to the roots (systemic uptake). Residual activity of NeemAzal-T was tested by caging 2nd instar larvae on plants that had been sprayed with neem solutions one hour to three weeks in advance. Oviposition was reduced to half the number of eggs per plant by the neem treatment. The number of eggs that hatched was not affected by the neem treatment, but development of these larvae was strongly inhibited and all larvae in the neem treatment died within two weeks without reaching 2nd instar. The concentration of the active ingredient azadirachtin-A (the azadirachtin component in NeemAzal-T) needed to protect plants from damage by 2nd instar larvae was 8 "g ml-1. The lethal doses for 2nd instar larvae were determined by probit analysis to be 6.2 and 11.2""g ml-1 for LC50 and LC95 respectively. NeemAzal-T protected plants from damage for at least 3 weeks if applied before oviposition, or at least 2 weeks if applied against 2nd instar larvae. In these studies, neem inhibited oviposition, larval development and feeding, and greatly increased mortality.