Lipid Oxidation in Walnut Flour: The Role of Oleosomes in their intact matrix

Lipid Oxidation in Walnut Flour: The Role of Oleosomes in their intact matrix

Acevedo-Estupinan, M.V., Decker, E.A.

Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA

Lipid oxidation in food systems remains a complex and challenging area of research, despite decades of study. While the mechanisms of lipid oxidation are well-established, the interplay of various factors in real-world food matrices often leads to unexpected behaviors. Oleosomes, plant organelles known for their ability to store polyunsaturated lipids, have emerged as a focal point in recent investigations. However, their role in the context of the entire food matrix, such as walnut flour, remains poorly understood due to the diverse molecular species involved in lipid oxidation.

This study investigated the impact of walnut flour's physicochemical properties, including its oleosomes, on lipid oxidation. We analyzed intact walnut flour, walnut flour with reduced surface lipids and extracted walnut oil for tocopherol oxidation, antioxidant capacity, and the formation of primary and secondary lipid oxidation products.

Our results revealed differences in oxidation behavior in intact walnut flour compared to extracted oil. While all tocopherols were consumed in extracted oil in the lag phase, intact walnut flour exhibited a more complex antioxidant defense, with only 20% of total tocopherols oxidized during that time. total Antioxidant capacity decreased more than tocopherols during storage indicating that other antioxidants were involved in oxidative stability.

Understanding the oxidation mechanisms in foods containing oleosomes is crucial for developing novel antioxidant technologies to increase food safety and decrease waste.