Effect of bagging on nutritional quality and mineral element content of peach fruit in different varieties

【Objective】Bagging is a significant practice in peach cultivation, which can alter the light conditions of the fruit and minimize mechanical damage to the fruit, enhance surface smoothness, and improve the overall visual quality of peaches. Additionally, bagging can reduce pesticide residues on peaches, thereby decreasing food safety risk. However, research on the impact of bagging on the nutritional quality of peach fruit is limited. The study aimed to evaluate the impact of bagging on the nutritional quality and mineral element content of peach fruit in various varieties.【Methods】Three peach varieties from Jiangsu including Baifeng, Xiacui, and Xiahui were tested. The treatment group underwent bagging, while the control group remained untreated. The peach samples at maturity stages were collected, and the fruit mass, firmness and soluble solid content were detected. The content of amino acids, organic acids and total phenols were detected. Mineral elements including macronutrients and micronutrients were analyzed using ICP and ICP-MS.【Results】Among the three varieties, Xiahui had the highest average mass (279.1 g), followed by Baifeng (248.3 g) and Xiacui (220.0 g). Xiacui exhibitedthe highest firmness (5.80), which was 1.87 times and 1.62 times that of Baifeng and Xiahui, respectively. There were no significant differences in the soluble solids content among the different varieties, which ranged from 10.4% to 11.1% (p＞0.05). For each variety, there were no significant differences in mass and firmness between the bagged and control samples (p＞0.05). However, compared with the unbagged group, the soluble solids content in the bagged group significantly decreased for Baifeng, Xiahui, and Xiacui by 16.6%, 7.5%, and 17.9%, respectively (p＜0.05). Tthe contents of vitamin C, amino acids, and total phenols in the bagged group, were significantly lower than those in the control group, with reductions of 0.14-0.22, 0.07-0.11 and 0.11-0.25 times, respectively (p＜0.05). The soluble sugar content in the bagged group significantly increased by 0.12- 0.24 times in Xiahui and Xiacui, but showed no significant change in Baifeng (p＜0.05). The bagging significantly increased the contents of succinic acid and citric acid in Baifeng. In Xiacui, bagging significantly elevated the contents of succinic acid, quinic acid, and malic acid, and decreased the citric acid content significantly. Overall, the total acid content of bagged fruits in Xiahui was significantly reduced compared with the control fruits. Bagging significantly decreased the levels of Ca, Cu, K, Mg, Sr, Zn, and Ba in all three peach varieties, with reductions ranging from 0.1 to 0.8 times (p＜0.05). Additionally, the bagging reduced the Mn and Al contents in Xiacui and Xiahui by 0.2-0.5 and 0.1-0.2 times, respectively. The reductions in amino acids and mineral elements might be attributed to the effect of bagging on reducing the opening of fruit stomata, leading to decreased water influx and consequently lower levels of photosynthetic products and mineral elements in the peaches. The decrease in total phenol content might be related to reduced fruit coloration due to bagging.【Conclusion】The bagging did not affect fruit mass or firmness but significantly reduced the contents of soluble solids, vitamin C, amino acids, total phenols, and most mineral elements, leading to reduce the nutritional quality of the peach fruits. These findings would provide valuable insights for the assessment of peach cultivation practices.