Chemical composition of walnuts from three regions in China

To reveal the characteristic chemicals of walnuts from different origins, we analyzed fatty acid composition, tocopherols, phytosterols and total phenolic content (TPC) of walnuts from three main producing regions in China. The results showed that walnuts were rich in polyunsaturated fatty acids, and the ratio of ω-6 to ω-3 fatty acids was close to the recommendation of Chinese Nutrition Society. Moreover, walnuts contain high contents of tocopherols (331.20–414.71 ​mg/kg), phytosterols (97.17–110.35 ​mg/100 ​g) and phenols (38.51–48.08 ​mg GAE/kg). Significant chemical differences exist among walnuts from three production regions. The highest content of polyunsaturated fatty acids was found in walnuts from the northern China, the highest content of tocopherols in walnuts from southwest China, and the highest contents of phytosterol and TPC in walnuts from northwest China. However, there was no significant difference in the tocopherol, phytosterol and TPC content of walnuts between the Northern China and Northwest China. The above results provide important references for manufacturers and consumers to select suitable walnut scientifically and reasonably.