Nutritional value of cold-pressed rapeseed oil during long term storage as influenced by the type of packaging material, exposure to light & oxygen and storage temperature

摘要

The effect of various conditions (storage temperature, exposure to light, access of oxygen) and different packaging material (amber glass, amber polyethylene terephthalate) on the nutritional value of cold-pressed rapeseed oil during 12 months of storage was investigated. Quantified quality parameters included: acidity, peroxide value, spectrophotometric indices (K-232 , K-268 ), fatty acid composition, tocopherols and sterols. Storage of oil at 4 degrees C was found to be most appropriate for maintaining the quality of cold-pressed rapeseed oil. Exposure of oil samples stored at room temperature to light in combination with the access of oxygen caused the most pronounced losses in the total tocopherols (ca. 90-91 % of alpha-T, and ca. 80-81 % of gamma-T), total phytosterols (ca. 15-16 %) and substantial deterioration in oil qualitative properties. Although storage at room temperature is common for use in households, storage of at low temperatures (4 degrees C) significantly increases the possibility of prolonged shelf life of cold-pressed rapeseed oil.