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Browsing by Subject "valaistus"

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  • Sian kausilisääntymisen endokrinologiasta 
    Hälli, Outi (University of HelsinkiHelsingin yliopistoHelsingfors universitet, 1999)
    Tutkimuksen tavoitteena oli selvittää sian kausilisääntymisen endokrinologista perustaa. Haluttiin nähdä villi- ja kesysian erot ja yhtäläisyydet niiden melatoniinin erityksessä ja vuorokauden- ja vuodenaikaan sidotuissa rytmeissä. Kausilisääntymisen syiden ymmärtämisellä pyritään syyshedelmättömyysongelman parempaan hallintaa. Tutkimus toteutettiin neljänä erinäyttenottokertana: keväällä, kesällä, syksyllä ja talvella. Yhteensa 20 kesysiasta ja 20 villisiasta otettiin 48 tunnin ajan verinäyteitä kahden tunnin välein. Siat pidettiin luonnon valaistuksessa näytteenoton ajan. Näytteistä määritettiin melatoniini Buhlman melatoniini-RIA-menetelmällä. Tuloksissa villi- ja kesysiolla melatoniinin erityksessä ei ollut eroa. Erot olivat suuremmat yksilöiden kuin rotujen välillä. Molemmilla roduilla näkyy selkeä vuorokaudenaikainen melatoniinirytmi. Melatoniinipitoisuus nousee pimeänä aikana ja on perustasolla valoisana aikana. Toisin kuin aiemmin on oletettu sika näyttäisi melatoniinin suhteen käyttäytyvän samoin kuin selkeä lyhyen päivän kausilisääntyjä lammas. Niinpä sikataloudelle ongelmallinen kausilisääntyminen on sialle fysiologista. Yksilöiden välisestä vaihtelusta johtuen on mahdollista, että tietyt yksilöt ovat herkempiä kausilisääntymiselle, jolloin ympäristön merkitys ongelman esilletulossa korostuu.
  • Valon vaikutus rucolan laatuun ja tokoferoleihin varastoinnin aikana 
    Salonen, Sonja (2020)
    Leafy vegetables are quickly perishable foods that are usually stored in bright lighting and transparent packaging. They contain a lot of bioactive components, which are easily destructed by lighting. Rocket (arugula) contains a lot of vitamin E, vitamin C and folate and there are not many studies about rocket. The aim of this study was to investigate how lighting affects the vitamins and quality of rocket during storage. In addition to lighting, the effect of different packaging materials, their light transmittances and their perforations to rocket’s sensory quality and tocopherols contests were studied. The hypothesis of the study was that when stored under lighting, the spoilage of samples is faster than when stored in dark and that perforated bags have the weakest preservation of sample quality and vitamins. Rocket samples were stored under three different lighting conditions which were continuous darkness, continuous fluorescent light (65 μmols-1m-2) and continuous LED light (125 μmols-1m2). The rocket was packaged in five different plastics (OP20, OP20-30-35, PET12-PE40, OPP20CP30, PET30-PE40) and there were perforated and non-perforated versions of them. A weeklong storage test was carried out in a chamber with constant conditions (5 °C, RH 40–50 %) and measurements were performed on days 1, 5 and 7. The tocopherol content of rocket was analyzed from lyophilized day 7 samples later by HPLC. The results of this study imply that lighting reduces the color and sensory quality of the packaged rocket, so the hypothesis was partly fulfilled. However, the spoilage was not significantly faster in the perforated materials. Lighting affected the gas composition of the bags through photosynthesis and respiration, as the oxygen and carbon dioxide concentrations remained unchanged, while in the dark the oxygen content decreased, and the carbon dioxide content increased. The quality of the rocket was best preserved in dark, as in LED and fluorescent light the samples lightened and yellowed faster and the structure of the samples deterioraetd. When stored in dark, non-perforated materials retained the alpha-tocopherol content of the rocket better than the perforated materials. Conversely, when stored in light, rocket packed in perforated materials had higher alpha-tocopherol contents than the those packed innon-perforated materials. The maximum differences in alpha-tocopherol contents between the rocket samples in different lighting conditions were 180 µg/g for the samples in non-perforated materials and 50 µg/g for the samples in perforated materials. The opaque materials (OPP20-CPP30 and PET30-PE40) retained the sensory quality of the rocket better than the transparent ones. There were no significant differences in alpha-tocopherol contents between the samples in different materials.
  • Valon vaikutus rucolan laatuun ja tokoferoleihin varastoinnin aikana 
    Salonen, Sonja (2020)
    Leafy vegetables are quickly perishable foods that are usually stored in bright lighting and transparent packaging. They contain a lot of bioactive components, which are easily destructed by lighting. Rocket (arugula) contains a lot of vitamin E, vitamin C and folate and there are not many studies about rocket. The aim of this study was to investigate how lighting affects the vitamins and quality of rocket during storage. In addition to lighting, the effect of different packaging materials, their light transmittances and their perforations to rocket’s sensory quality and tocopherols contests were studied. The hypothesis of the study was that when stored under lighting, the spoilage of samples is faster than when stored in dark and that perforated bags have the weakest preservation of sample quality and vitamins. Rocket samples were stored under three different lighting conditions which were continuous darkness, continuous fluorescent light (65 μmols-1m-2) and continuous LED light (125 μmols-1m2). The rocket was packaged in five different plastics (OP20, OP20-30-35, PET12-PE40, OPP20CP30, PET30-PE40) and there were perforated and non-perforated versions of them. A weeklong storage test was carried out in a chamber with constant conditions (5 °C, RH 40–50 %) and measurements were performed on days 1, 5 and 7. The tocopherol content of rocket was analyzed from lyophilized day 7 samples later by HPLC. The results of this study imply that lighting reduces the color and sensory quality of the packaged rocket, so the hypothesis was partly fulfilled. However, the spoilage was not significantly faster in the perforated materials. Lighting affected the gas composition of the bags through photosynthesis and respiration, as the oxygen and carbon dioxide concentrations remained unchanged, while in the dark the oxygen content decreased, and the carbon dioxide content increased. The quality of the rocket was best preserved in dark, as in LED and fluorescent light the samples lightened and yellowed faster and the structure of the samples deterioraetd. When stored in dark, non-perforated materials retained the alpha-tocopherol content of the rocket better than the perforated materials. Conversely, when stored in light, rocket packed in perforated materials had higher alpha-tocopherol contents than the those packed innon-perforated materials. The maximum differences in alpha-tocopherol contents between the rocket samples in different lighting conditions were 180 µg/g for the samples in non-perforated materials and 50 µg/g for the samples in perforated materials. The opaque materials (OPP20-CPP30 and PET30-PE40) retained the sensory quality of the rocket better than the transparent ones. There were no significant differences in alpha-tocopherol contents between the samples in different materials.

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