Comparison of phenolic compounds, tocopherols, phytosterols and antioxidant potential in Zhejiang pecan [Carya cathayensis] at different stir-frying steps

- Stir-frying is the main processing method of C. cathayensis.
- No studies are focused on its change during stir-frying process.
- We studied the impact of heating on nutritions and antioxidant of C. cathayensis.
- We studied the antioxidant change, including water-soluble and oil-soluble part.
- We studied phenolic acid, tocopherol and phytosterol of C. cathayensis first time.

The effect of stir-frying Carya cathayensis kernels at varying temperatures (200 °C-400 °C) and time periods (10 min-30 min) on total phenolic contents (TPC), phenolic acids, tocopherols, phytosterols and antioxidant capacity was investigated. The concentrations of TPC, phenolic acids, tocopherols and phytosterols in raw C. cathayensis kernels were 19.4 mg gallic acid equivalent/g dry weight, 3.67 mg/g, 79.5 μg/g and 1.00 mg/g, respectively. The antioxidant from the water and the oil-soluble part of C. cathayensis kernels were 78.3 mg Trolox equivalent/g dry weight (DPPH radical-scavenging activity) and 0.03 mg meq/kg (Peroxide value), respectively. Stir-frying at a low temperature over a short time period led to an apparent increase of the studied compounds and antioxidant capacity. However, these values decreased with heating time and temperature increased. In conclusion, it is benefit for stir-frying at a suitable temperature and over a suitable time period during the processing of C. cathayensis.