Analysis of the contents of mineral elements and amino acids in wild apricot kernels from Ili Region of Xinjiang

Abstract: 【Objective】Xinjiang wild apricot (Prunus armeniaca L.) is widely distributed in the Ili Valley, north of Tianshan Mountain. It is highly productive and plays an important role in cultivation and evolutionary origins. However, it is rarely utilized. It has been experimentally shown that the size of fruits and seeds decreases with increasing altitude in wild apricot populations. In addition to this, Huang Xue analyzed the wild apricot in terms of its amygdalin content, which averaged 31.32 mg·g-1 . However, in addition to the presence of amygdalin, the apricot kernel is also rich in unexplored nutrients. For example, mineral elements and amino acids are important components that help the human body to metabolize and grow better. However, the analysis of mineral nutrients and amino acids in wild apricot kernel is still unclear, hindering the evaluation and utilization of wild apricot kernel resources. The aim of this study was to analyze the mineral and amino acid compositions of wild apricot kernel. The data provided in this study can screen out apricot resources with high nutritional value. It provides theoretical reference for the development and utilization of wild apricot germplasm resources in Xinjiang.【Methods】The materials for this experiment were selected from 30 different types of wild apricot trees in Xinjiang with similar age and tree vigor, consistent soil type and uniform distribution. The mineral composi-tion and content of apricot kernels were investigated by the atomic absorption spectroscopy and atomic emission spectroscopy method. The amino acid composition and content of apricot kernels were investigated by the high performance liquid chromatography (HPLC). The nutrient composition of the experimental materials was determined by systematic description, correlation analysis, principal component analysis, and comprehensive evaluation of nutrient composition. These data were organized by Excel, correlation graphing was performed by Origin 2021, and principal component analysis and comprehensive analysis were conducted by SPSS 26.0.【Results】(1) The variation coefficients of mineral element contents were 7.78%-22.12%. The contents of eight mineral elements in apricot kernels were ranked as follows: potassium＞magnesium＞calcium＞sodium＞zinc＞iron＞copper＞manganese. Total mineral elements were the highest at 10 590.93 mg · g- 1 . Potassium had the highest average content, ranging from 3 595.67 to 6 091.52 mg · g- 1 . Manganese had the lowest average content, ranging from 5.50 to 11.11 mg · g- 1 . This was not in complete agreement with the results of some other studies on cultivated apricots, which may be due to geographic and climatic differences. These factors may lead to the fact that the contents of mineral elements absorbed and accumulated in the kernel were not completely consistent. (2) The variation coefficients of 17 amino acids ranged from 18.37% to 50.16%, with a wide range of variation. The average ratio of essential amino acids to total amino acid content was 32.47%, which was similar to the results of Sheng Xiaona’s study on essential amino acids to total amino acid content of sweet apricot kernel. The highest average amino acid content was Glu (6.62%) and the lowest was His (0.03%). The average percentage of medicinal amino acids to the total amino acid content was 75.61%, and the wild apricot of Xinjiang had a great potential for medicinal development, showing a result that was consistent with the findings of Huang Xue. Compared with the FAO/WHO model values, the average percentage values of Phe and Tyr were 1.5 times higher than the model values. The amino acid corresponding to the minimum value of RCAA was the first limiting amino acid. As the first limiting amino acid, the sum of Met and Cys accounted for 30% and the sum of Lys accounted for 70%. The SRCAA ranged from T30 (51.59) to T16 (73.04). (3) The correlation matrix showed that Zn showed highly significant positive correlation with Fe (0.58), EAA (0.54), NEAA (0.55), and TAA (0.55). Mg showed a positive correlation with K (0.44). Mg showed a significant negative correlation with Ca (-0.40). (4) The four principal components with high contribution were obtained using principal component analysis with a cumulative variance contribution of 83.171% .【Conclusion】Xinjiang wild apricot resources have great potential for development in terms of mineral elements and amino acids. The comprehensive quality evaluation model established in this experiment can be used for apricot kernel quality evaluation of Xinjiang wild apricot germplasm resources. Among them, T02, T14, T19 and T20 can be used as excellent apricot kernel germplasm resources. The kernels of different germplasm resources of Xinjiang wild apricot showed various nutritional values, which should be considered comprehensively to provide a reference for balancing the intake of mineral nutrients and amino acids.