Lipoxygenase activity in walnuts and almonds

The objective of this experiment was to investigate lipoxygenase (LOX) activity in walnut or almond homogenates. Walnut or almond kernels were heated with hot air at 55 °C for 2 or 10 min, or 60 °C for 2 or 10 min. The homogenates of untreated or heat treated walnut kernels exhibited greater LOX activity than the homogenates of untreated or heat treated almond kernels. Short-time heat treatments of 55 °C for 2 min or greater reduce LOX activity, retard the development of oxidative rancidity, and extend the shelf-life of walnuts and almonds during distribution and storage. Short-time heat treatments of walnut or almond kernels designed to control insect pests for international trade did not promote rancidity when compared to untreated walnuts or almonds.