Comprehensive quality evaluation of fermented-steaming Fructus Aurantii based on chemical composition, flavor characteristics, and intestinal microbial community.

Fructus Aurantii (FA) is an edible and medicinal functional food used worldwide that enhances digestion. Since raw FA (RFA) possesses certain side effects for some patients, processed FA (PFA) is commonly used in clinical practice. This study aimed to establish an objective and comprehensive quality evaluation of the PFA that employed the technique of steaming and fermentation. Combined with the volatile and non-volatile components, as well as the regulation of gut microbiota, the differentiation between RFA and PFA was analyzed. The results showed that the PFA considerably reduced the contents of flavonoid glycosides while increasing hesperidin-7-O-glucoside and flavonoid aglycones. The electronic nose and GC-MS (Gas chromatography/mass spectrometry) effectively detected the variation in flavor between RFA and PFA. Correlation analysis revealed that eight volatile components (relative odor activity value [ROAV] ≥ 0.1) played a key role in inducing odor modifications. The original floral and woody notes were subdued due to decreased levels of linalool, sabinene, α-terpineol, and terpinen-4-ol. After processing, more delightful flavors such as lemon and fruity aromas were acquired. Furthermore, gut microbiota analysis indicated a significant increase in beneficial microbial taxa. Particularly, Lactobacillus, Akkermansia, and Blautia exhibited higher abundance following PFA treatment. Conversely, a lower presence of pathogenic bacteria, including Proteobacteria, Flexispira, and Clostridium. This strategy contributes to a comprehensive analysis technique for the quality assessment of FA, providing scientific justifications for processing FA into high-value products with enhanced health benefits. PRACTICAL APPLICATION: This study provided an efficient approach to Fructus Aurantii quality evaluation. The methods of fermentation and steaming showed improved quality and safety.

Determination of Ten Flavonoids in the Raw and Fermented Fructus Aurantii by Quantitative Analysis of Multicomponents via a Single Marker (QAMS) Based on UPLC.

Fermented Fructus Aurantii (FFA) is widely used in South China for the treatment of functional dyspepsia. Naringin, neohesperidin, and other flavonoids are the main pharmacodynamic components of FFA. A new method is presented for the simultaneous determination of 10 flavonoids (including flavonoid glycosides and aglycones) in FFA using the quantitative analysis of multicomponents via a single marker (QAMS) approach and is used to investigate changes in flavonoids during fermentation. The viability and precision of QAMS were validated against the ultrahigh-performance liquid chromatography (UPLC), with various UPLC instruments and chromatographic conditions being evaluated. Differences between raw Fructus Aurantii (RFA) and FFA were examined using orthogonal partial least squares discrimination analysis (OPLS-DA) and content determination. The influence of various fermentation conditions on flavonoids was also investigated. There were no appreciable differences between the QAMS and the external standard method (ESM), demonstrating that QAMS is an improved method for the determination of FA and FFA. FFA and RFA can be readily distinguished based on OPLS-DA chemometric modelling and the corresponding chromatograms. In addition, the flavonoid changes after fermentation. Fermentation considerably reduced the contents of flavonoid glycosides, while increasing hesperidin-7-O-glucoside and flavonoid aglycones. Moreover, fermentation conditions impact multiple flavonoids in FA, so controlling these conditions is necessary for the quality control of fermented FA products. This QAMS approach is useful for detecting numerous components in RFA and FFA simply, quickly, and efficiently, thus strengthening the quality control of FA and its fermented products.