Effects of seed damage on the oxidative stability of poppy seed oil

This study was conducted to assess the reduction of life time and quality of poppy seeds considering a mechanical damage, which may occur during harvesting. Poppy seeds were crushed to receive 90%, 80%, 70%, 60% and 50% intact seeds, the undamaged 100% intact seeds served as controls. The samples were stored at 40°C for 175 d and oxidation experiments performed periodically by assessing conjugated dienes, p-anisidine reactive products, the iodine value, the acid value and γ-tocopherol content. With increasing degree of mechanical damage the shelf life declined, the oxidation products were formed more rapidly and the main antioxidant in poppy seeds γ-tocopherol was consumed. Considering the reduction of life time by including all quality parameters the shelf life of the 10% damaged seeds was reduced by 50.5%. This reduction was reached up to 82% for the 50% damaged seeds compared to the control. A high correlation was found between the increase in oxidation products and the degradation of γ-tocopherol. This study show that increased damage during harvesting (10-50%) is responsible for a faster loss of product quality especially in seeds containing high amounts of polyunsaturated fatty acids like poppy seeds.