Nutritional properties of oat-based beverages as affected by processing and storage

Oat-based beverages enriched with vitamins and minerals were produced with common hydrothermal treatments and stored at 22 degrees C for 64 weeks. The effects of decanting on the retention of native vitamins, minerals and fatty acids, and different UHT holding time (5 s or 20 s) at 140 degrees C on vitamins were investigated. Fatty acid profile, vitamin retention and dissolved oxygen concentration were monitored during storage. The decanting process caused a 47% increase of vitamin 136 and a 45-74% loss of phosphorus, zinc, calcium and iron. The steam-injection UHT treatment caused a 60% loss of vitamin D-3 for both holding times and a 30% loss of vitamin B-12 for 20 s. During 1 year of storage, oleic and linoleic acids were stable, whereas linolenic acid decreased only slightly, even in the iron-enriched variety. The dissolved oxygen concentration increased to a low value of 0.71 mg L-1 and reached a balance after 16 weeks. Most enriched vitamins except vitamins A, D-3 and B-12 were stable during ambient storage. Oat-based beverages with highly retained vitamins can be manufactured by adding vitamins prior to direct UHT treatment with a shorter holding time. Additionally, iron enrichment of such beverages, without affecting the fatty acid profile, can be achieved by filter sterilisation.