Effect of storage time and temperature on stability of bioactive compounds in aseptically packed beverages prepared from rose hips and sea buckthorn berries

Rose hips and sea buckthorn berries contain high amounts of beneficial bioactive compounds. In this study the content and stability of natural vitamins and antioxidants were investigated in two fruit beverages made from rose hip powder, sea buckthorn berry purée and white grape juice concentrate, and wheat germ oil in one of the beverages. Beverages were formulated, pasteurised and filled aseptically in Tetra Brik packages and stored up to 35 days at 4 °C or 22 °C. Samples were analysed for the content of ascorbic acid, carotenoids, major phenolics, tocochromanols, total phenols and total antioxidant capacity as ferric reducing ability. The largest changes occurred during the first 5 days of storage, thereafter mainly ascorbic acid decreased. In the wheat germ oil supplemented beverage, α-tocopherol was more rapidly degraded. Negative correlations between the decrease of some carotenoids and tocochromanols, and the increase of some phenolics, suggest relationships of redox reactions specific to the amount of oil supplemented. From the present study we can conclude that additions of oil to beverages should be carefully selected to avoid oxidations of bioactive compounds. Furthermore, packaging of the beverages should be carried out at higher temperatures and thereafter it should be stored at low temperatures (4 °C), which decreased oxidation of all bioactive compounds except ascorbic acid.