Relationship between antioxidant properties and chemical composition of the oil and the shell of pecan nuts [Caryaillinoinensis (Wangenh) C. Koch]

The chemical composition, oxidative stability, total phytosterols and tocopherols of pecan nut oil; the composition, color parameters and infrared spectroscopy of the pecan shell powder; the total phenolic compounds, condensed tannins and antioxidant activity (ABTS and DPPH) in extracts obtained by infusion of the pecan nut shell powder, were determined for samples of two consecutive years and different varieties. Furthermore, the possible effects caused by the use of spray drying technology were assessed. There was a significant effect for different harvest year and variety for sample quality and nutritional content of phytochemicals in the oil and nutshell. The results indicated a relationship between the content of unsaturated fatty acids present in the oil and the concentration of antioxidant compounds in the shell. Although phenolic compounds are considered to be thermally unstable, no significant losses were observed after the spray-drying process.

► Pecan crop year and variety significantly affected quality of oil and nut shells.
► Pecans with higher polyunsaturated fats showed greater total phenolics and antioxidant activity.
► Phenolics content in protective outer shell directly related to composition and stability of oil.