Influence of Hull and Impurity Content in High-Oleic Sunflower Seeds on Pressing Efficiency and Cold-Pressed Oil Yield

This study investigates the effects of hull and impurity content on the efficiency of cold-pressing high-oleic sunflower seeds using a screw press. High-oleic sunflower oil is valued for its oxidative stability and health benefits, and optimizing pressing conditions is crucial for maximizing yield and maintaining oil quality. The identification of high-oleic sunflower oil was performed by analyzing its fatty acid composition, iodine value, and refractive index. Eleven seed samples with varying hull and impurity contents were processed to assess their impact on cake composition, pressing efficiency, and pressing oil yield. Oil yield ranged from 39.24% to 76.52%, with higher hull content contributing to increased yield due to its role in facilitating oil drainage. Multiple linear regression models were developed to predict moisture and oil content in the cake, as well as pressing efficiency, based on hull and impurity content, demonstrating strong predictive accuracy. These parameters were selected as they represent economically significant indicators, given that moisture and oil content indirectly reflect the protein content in the cake, while sunflower cake is primarily used as animal feed. Additionally, pressing efficiency indicates oil yield during pressing, which is the most critical economic parameter of the cold-pressing process. Cluster analysis identified three sample groups with distinct characteristics, revealing interactions between seed composition and pressing performance. The results highlight the significance of seed preparation in optimizing cold-pressing efficiency and provide insights for improving oil extraction processes. These findings support the industrial application of high-oleic sunflower seed pressing and contribute to the development of sustainable, high-quality oil production methods.