Tracing the Origins of Blueberries by Their Mineral Element Contents and 87Sr/86Sr Ratios

Abstract

This study investigated the feasibility of using the mineral element contents and ⁸⁷Sr/⁸⁶Sr ratios of blueberries to trace their origins. The contents of 28 mineral elements, including K, Al, and Mg, were determined in 104 blueberry samples from three blueberry-producing areas in Guizhou Province, China. Also determined were both the ⁸⁷Sr/⁸⁶Sr ratios in 48 blueberry samples as well as the type of soil in which the blueberries were grown. Cluster analysis of ⁸⁷Sr/⁸⁶Sr ratios, stepwise discriminant analysis of mineral element contents, and combined discriminant analyses of ⁸⁷Sr/⁸⁶Sr ratios and mineral element contents were done. The results show that ten elements (Ca, Cr, Cs, Mg, Mn, P, Rb, Sb, Th, and Y) were selected by linear discriminant analysis, which could be used to establish the provenance traceability model of blueberries in Guizhou. The original accuracy of linear discriminant analysis was 89.4%, and the accuracy of cross-validation was 83.6%. When ⁸⁷Sr/⁸⁶Sr ratios were used for tracing, the accuracies of both the original discrimination and the cross-validation were 81.3% as determined by linear discriminant analysis, and the accuracy rate of origin discrimination was 81.25% by cluster analysis. The results of combined discrimination were the best: the accuracy of the original discrimination was 95.8%, and the accuracy of cross-validation was 93.8%. Mineral element contents and ⁸⁷Sr/⁸⁶Sr ratios can be used to trace the origins of blueberries, and combining them can significantly improve the discrimination accuracy. Fisher linear discriminant analysis had the greatest accuracy followed by cluster analysis, while principal component analysis was relatively poor in the research of Guizhou blueberry origin traceability.

Keywords: 87Sr/86Sr; Blueberry; Mineral elements; Origin traceability.