| In order to develop and utilize the walnut resources in Yunnan, the contents of neurotransmitters (tryptophan, 5-hydroxytryptophan, 5-hydroxytryptamine, melatonin)in the kernels, fatty acids and endogenous antioxidant components (β-carotene, squalene, β-sitosterol, and tocopherol) in the oil of the eight major walnut cultivars in Yunnan were determined, and the similarity of the eight major cultivars in Yunnan was evaluated by using principal component analysis. The results showed that the contents of tryptophan, 5-hydroxytryptophan, 5-hydroxytryptamine and melatonin in kernels of eight major walnut cultivars in Yunnan were (0.02±0.00)-(0.08±0.01) mg/g, (11.40±0.83)-(38.84±1.38) μg/g, (2.99±0.62)-(12.31±1.01) mg/g, and (3.95±0.55)-(1900±1.47)ng/g, respectively. The unsaturated fatty acid content in eight major cultivars walnut oil was 88.94%-92.67%, and the ratio of ω-6 to ω-3 polyunsaturated fatty acid content in oil was 5.32-13.29. The contents of four endogenous antioxidant components in eight major cultivars walnut oil were β-carotene (7.21±0.30)-(1730±0.20) μg/g, squalene (319.41±543)-(1 293.00±13.00) μg/g, β-sitosterol (214.29±4.00)-(382.86±6.49) μg/g, (α+γ)-tocopherol (292.41±4.26)-(1 285.60±7.22) μg/g, and the tocopherol in the Yuanboluo and Niangqing walnut oil with higher tocopherol content had some pro-oxidant risk. After principal component analysis, the eight major walnut cultivars could be divided into four groups according to the contribution value of components. Among them, Xixiang and Niangqing walnut was a group, Santai, Yangbipao and Dama walnut was a group, Dashake and Dabaike walnut was a group, and Yuanboluo walnut was grouped separately. In conclusion, walnuts in Yunnan are rich in a variety of nutrients, and have the value of in-depth development and utilization. |
