Nutritional quality analysis of distinct walnut accessions in Bazhong, Sichuan

To clarify the nutritional quality differences between local walnut strains from the Bazhong region of Sichuan and Juglans regia 'Qingxiang', a systematic analysis was conducted on seven local walnut strains from Bazhong City, Sichuan, compared with the Juglans regia 'Qingxiang'. The contents of protein, fat, ratio of linoleic acid to α-linolenic acid, vitamin B₂, vitamin E, and mineral elements such as iron, zinc, selenium, and strontium were measured. The results showed that there were differences in various nutritional indicators among the different walnuts. The protein content ranged from 14.9 to 19.4 g/100 g, with the highest observed in Walnut No.8. The fat content ranged from 64.5% to 69.03%, with the highest found in Walnut No.2. The ratio of linoleic acid to α-linolenic acid mostly fell within the range of 5~10, with Walnut No.7 exhibiting a ratio of 5.43, which aligns with the recommended dietary nutrition guidelines. Variations were also observed in the contents of vitamin B₂ and vitamin E among the walnuts. The vitamin B₂ content in local Bazhong walnuts was generally higher than that in the Juglans regia 'Qingxiang'. With the exception of Walnut No.2 and Walnut No.4, which had lower vitamin E content compared to the Juglans regia 'Qingxiang', the vitamin E content in the remaining local Bazhong walnuts was significantly higher. Mineral element analysis revealed that Walnut No.6 from Bazhong had the highest iron and zinc contents. Selenium was only detected in some local Bazhong walnuts, with the highest level found in Walnut No.4. Additionally, the strontium content in most local Bazhong walnuts was significantly higher than that in the control group. Through a comprehensive evaluation of the key nutritional qualities of different walnuts from Bazhong, Sichuan, this study provides a scientific basis for selecting high-quality walnut varieties suitable for the ecological conditions of Bazhong, Sichuan, and for subsequent functional development.