Effects of different drying methods on Rubus chingii Hu fruit during processing

In this study, the dried fruits of Rubus chingii Hu (Chinese name: Fu-Pen-Zi; FPZ) were processed and dried by three methods-in the shade, the sun, and the oven. The composition regarding the standard ingredient, color, and antioxidant capacities were investigated pro- and post-processing. The technique of headspace-solid-phase-microextraction-gas-chromatography-mass spectrometry (HS-SPME-GC-MS) and flavoromics were used to analyze the flavor-conferring metabolites of FPZ. The results obtained revealed that the highest use value and antioxidant capacities were detected in the FPZ fruits processed and dried in the shade. A total of 358 metabolites were detected from them mainly consisting of terpenoids, heterocyclic compounds, and esters. In differential analysis, the down-regulation of the metabolites was much greater than their up-regulation after all three drying methods. In an evaluation of the characteristic compounds and flavors produced after the three methods, there were variations mainly regarding the green and fruity odors. Therefore, considerable insights may be obtained for the development of novel agricultural methods and applications in the pharmaceutical and cosmetic industries by analyzing and comparing the variations in the chemical composition detected pre- and post-processing of the FPZ fruits. This paper provides a scientific basis for quality control in fruits and their clinical applications.