Impact of storage of oat bran flour and dispersion on lipid oxidation, odour profile, and oxidative degradation of beta-glucan

Abstract

Lipid oxidation induced oxidative degradation of beta-glucan could lead to technological, sensory, and nutritional challenges during food storage. This study aimed to explore the impact of storage of oat bran concentrate (OBC) flours and aqueous oat dispersions on lipid, beta-glucan, and odour properties. Formation of free fatty acids was observed in non-heat treated OBC flour during storage (12 weeks at 4-40 degrees C), indicating the activity of endogenous hydrolytic enzymes, while lipid oxidation was highest in heat-treated (HT) OBC flour. The molecular weight of beta-glucan remained the same, indicating that lipid oxidation did not induce oxidative degradation of beta-glucan in the flours. Fresh and 8 weeks at 40 degrees C stored HT OBC flours were used for the preparation of aqueous oat dispersions with and without 3 % rapeseed oil. No difference in the odour characteristics of dispersions prepared from fresh and stored OBC flours was found. However, 4 weeks at 22 degrees C storage of HT OBC dispersions had a significant effect on the odour in comparison to the freshly prepared dispersions. During the storage of the dispersions, oxidation of lipids was mild and degradation of beta-glucan was not detected. This study provides new insights into the impact of storage on dry and aqueous oat products.