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Alvenäs, Amanda, 2017. Antioxidants (avenanthramides, tocopherols and tocotrienols) in different oat (Avena sativa) cultivars before and after malting. Second cycle, A2E. Uppsala: SLU, Department of Molecular Sciences



Interest in oats has increased during recent years because of its health beneficial effects, mainly as foodstuff but also as a pharmaceutical. Oats contain unique phytochemicals, like the oat specific antioxidants called avenanthramides. Oats also contain high levels of unsaturated fatty acids which can lead to oxidation problems during processing. Antioxidants are currently added to oat products for this purpose. Malting of oat grains prior to processing might replace the added anti-oxidants since some studies have found that the avenanthramide amount has increased by the process. However, some other health beneficial compounds like tocols (Vitamin E) and β-glucan (fiber) might decrease by malting. In the present study, qualitative and quantitative properties of avenanthramides and tocols (to-copherols and tocotrienols) of 10 different oat cultivars were investigated, both before and after malting. Some of the oat groats (dehulled kernels) were malted before extraction but none of them germinated. Although, malting resulted in a significant avenanthramide increase by 238%, whereas tocol amount did not change significantly. This suggests that the food additives could be avoided by malting. Avenanthramide concentration varied a lot between cultivars. Amount increased most in the cultivars Belinda (+2943%) and SW151304 (+454%) but decreased in the cultivars Matilda (-71%) and Fatima (-63%). Belinda and SW151106 had the highest levels of avenanthramides after malting. However, large variations were observed for the malting duplicates of some cultivars regard-ing avenanthramide content. Generally, avenanthramide concentration was a bit lower than recorded by previous studies whereas tocol concentration was a bit higher. Antioxidant activity was higher after malting and largely it seemed to be attributed to the avenanthramides. In further studies, more cultivar analyses during controlled conditions are required and environmental and genotypic factors must be taken into consideration in order to assure cultivar variations. It is also of inter-est to analyse malting effects on β-glucan


Intresset för havre har under de senaste åren ökat på grund av dess hälsofrämjande egenskaper, främst som livsmedel men även som läkemedel. Havre innehåller unika fytokemikalier, till exempel de havrespecifika antioxidanter som kallas avenantramider. Havre innehåller höga halter av omättade fettsyror vilket kan orsaka oxidationsproblem under industriella processer. Det är vanligt att tillsätta antioxidanter för att undvika detta. Mältning av havrekärnor före den industriella processen skulle kunna ersätta de tillsatta antioxidanterna eftersom vissa studier har visat att avenantramidhalten ökar under mältningen. Halten av andra hälsofrämjande ämnen som tokoler (Vitamin E) och β-glukan (fiber) kan dock minska under mältningsprocessen. I denna studie undersöktes kvalitativa och kvantitativa egenskaper hos avenantramider och tokoler (tokoferoler och tokotrienoler) i 10 olika havresorter, både före och efter mältning. Vissa av havrekärnorna (skalade) mältades före extraktionen men ingen av dessa grodde. Ändå ökade avenantramidhalten signifikant efter mältningen med 238%, men tokolhalten ändrades inte signifikant. Resultaten tyder på att de tillsatta antioxidanterna skulle kunna ersättas av mältning. Avenantramidhalten varierade mycket i havresorterna. Halten ökade mest i sorterna Belinda (+2943%) och SW151304 (+454%) men minskade i sorterna Matilda (-71%) och Fatima (-63%). Belinda och SW151106 hade högst halt av avenantramider efter mältningen. Stora variationer inom mältningsduplikaten observerades dock i vissa av sorterna. Generellt var den uppmätta avenantramidhalten lägre än vad man funnit i tidigare studier medan tokolhalten var lite högre. Antioxidantaktiviteten var högre efter mältningen och verkade till största del bero på avenantramiderna. I framtida studier är det av intresse att analysera fler havreprover under kontrollerade förhållanden och omgivande och genotypiska faktorer behöver tas i beaktning för att några slutsatser gällande sortvariationer ska kunna dras. Det är också av intresse att analysera mältningens eventuella effekter på β-glukan.

Main title:Antioxidants (avenanthramides, tocopherols and tocotrienols) in different oat (Avena sativa) cultivars before and after malting
Authors:Alvenäs, Amanda
Supervisor:Dimberg, Lena
Examiner:Andersson, Roger
Series:Molecular Sciences
Volume/Sequential designation:2017:21
Year of Publication:2017
Level and depth descriptor:Second cycle, A2E
Student's programme affiliation:NY002 Agricultural Programme - Food Science 270 HEC
Supervising department:(NL, NJ) > Department of Molecular Sciences
Keywords:oats, oat cultivars, avenanthramides, tocols, malting
Permanent URL:
Subject. Use of subject categories until 2023-04-30.:Food science and technology
Deposited On:19 Feb 2018 09:40
Metadata Last Modified:13 Jun 2018 08:06

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