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Browsing by Subject "uppopaisto"

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  • Kaurapohjaiset snacksit 
    Kulin, Elisa (2020)
    In this thesis snack production and oats as a raw material for snacks were reviewed. Oat lipid oxidation and the shelf life of snack products made of oats was also considered. The aim of experimental studies was to find out if it is possible to puff baked snacks in the oven with high temperature without using yeast as a leavener. The test was conducted with two different baking temperatures and with and without added yeast. The shelf life of oat-based snacks with spice extract were also studied for 12 months by sensory evaluation. Lipid oxidation was also measured, and the product quality was determined by microbiological tests. Also, two consumer tests (number of panelists n = 30 and n = 118) were made with the snacks. Statistically there were no difference between two baking temperatures in doughs with yeast, but the higher temperature decreased the average error of snack samples heights. Yeast in the dough was significant. Sensory evaluation panel recognised the hidden, freshly baked reference sample from the actual samples at 6 months’ time. The results from the measurements of lipid oxidation on the effect of spice extract on snacks shelf life wasn’t clear and needs further investigation. The products microbiological quality stayed good the whole time monitored.
  • Rypsiöljyn laadun muutokset jatkuvatoimisessa paistoprosessissa 
    Peltomäki, Katja (2019)
    The literature part of the study dealt with frying methods, frying fats and oils, chemical and physical changes of frying fats and oils during the frying and analyse methods of frying fats and oils. The aim of the experimental part was to study changes in rapeseed oil quality during continuous frying process during three different frying periods. Especially the effect of day without production during the frying period was studied. Samples, frying oils, were taken every day during the different frying periods. In period one and two there was one day without production. Oils were stored in storage tanks during that time. In third period, there was production on every day. All samples were inspected for colour, odour, viscosity and clearness by visual methods. Also viscosity by rotation viscometer, smoking point, free fatty acids by titration method, fatty acid content and water content of samples was analysed. Based on sensory evaluation, the quality of oil deteriorated over thedays of use. Colour was darker, viscosity was higher and off-odours were sensed. Instrumental analyses indicate same kind of changes; viscosity and free fatty acid were increased and smoking point and amount of unsaturated fatty acid were decreased while frying time was increasing. In literature, also same changes were mentioned. There was changes in fatty acid content during the frying periods. More fatty acids characteristic to meat was detected in oils at the end of period than in fresh oils. Based on these results, oil quality remained acceptable in everyday use for a typical frying period of one week. Difference between fresh oil and used oils was clear but still acceptable. The amount of free fatty acids, and the level of viscosity and smoking points were under the limits applied in Finland. The day without production deteriorated oils quality substantially Reducing the amount of oil in process and having shorter frying periods or more efficient filtering of oils can help to keep the quality of frying oil better.

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