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Title: Cold pressed rapeseed oil : seed pre-processing technologies, chemical characterisation and spectroscopic authentication
Author: McDowell
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2017
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Cold pressed rapeseed oil is produced when the seeds from the Brassica napus crop are crushed at a low temperature. This research sought to investigate the extent seed pre-processing and cultivar could be used to alter the composition of cold pressed rapeseed oil in relation to bioactive compounds. It also aimed to characterise UK and Irish cold pressed rapeseed oils and compare them with other popular types of edible oils. Finally, a range of spectroscopic techniques and chemometric models were tested for their ability to detect the substitutional adulteration of cold pressed rapeseed oil with lesser value oils. With regards to cold pressed rapeseed oil pre-processing, microwaving and thermal roasting significantly increased the abundance of phenolic acids and the antioxidant activity of cold pressed rapeseed oil. The volatile composition was also significantly altered by these pre-processing techniques. Cultivar had little impact on chemical composition. Characterisation of a range of UK, Irish and French cold pressed rapeseed oils found that all oils adhered to quality parameters. French oils had significantly higher levels of antioxidant activity than UK or Irish. Cold pressed rapeseed oil had higher levels of phenolic acids than refined rapeseed oil and was also more stable under heat stress. Spectroscopic techniques (FT-IR, Raman, 400MHz NMR, 60 MHz NMR) were tested with chemometric models to see to what extent cold pressed rapeseed oil adulteration could be classified and quantified. Refined rapeseed oil adulteration in cold pressed rapeseed oil was best classified by the 400 MHz NMR, then Raman, FT-IR and 60 MHz NMR. Refined sunflower oil was best classified by the 400 MHz NMR, followed by FT-IR, then Raman and 60 MHz NMR. Levels of adulteration detection showed refined sunflower could be detected at lower levels than refined rapeseed oil.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available