The impact of storage on the primary and secondary metabolites, antioxidant activity and digestibility of oat grains (Avena sativa)

The effect of storage was studied on grain metabolites, functional properties and digestibility of three oat cultivars selected in Serbia - Dunav, Vrbas and NS Tara. During the 12 and 24 months of storage, there was a decrease on average in total proteins (10.98% and 15.95%) lipids (7.55% and 11.82%), crude cellulose (6.65% and 14.77%) and starch concentration (6.48% and 9.48%), and an increase in total ash concentration (4.8% and 9%) and dry matter (4.53% and 5.92%). Storage period caused a decrease in β-glucan concentration. The concentration of total phenolics (28.79-41.19%) and caffeic acid markedly decreased after 24 months of storage. The storage period significantly influenced the ferric reducing ability (FRAP) (36.34-43.12%) and the DPPH radical scavenging activity (76.92-237.14%). Organic matter digestibility of oat grains was slightly changed, but remained over 70%. Based on the present study, oat grain should not be stored longer than 12 months since phenolics contribute markedly to health promoting effect of oats.