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Douchi is a highly appreciated product due to its unique flavor, high nutritional value, and health benefits. Douchi from different regions exhibits distinct characteristics. The objective of this study was to investigate the volatile profiles in douchi produced from different geographical origins using gas chromatography-mass spectrometry (GC-MS) and chemometrics. The volatiles were extracted by headspace solid-phase micro-extraction (HS-SPME) and subsequently determined by GC-MS. A comparative analysis was further conducted to identify the variations in volatile compounds among the samples. The correlation between the samples was investigated by employing cluster analysis (CA) and principal component analysis (PCA). An orthogonal partial least squares-discriminant analysis (OPLS-DA) model was established to discriminate samples from different regions and identify key differential compounds. A total of 46 volatile compounds were detected, among which terpenes, alcohols were the main compounds. Furthermore, 14 key differentiating compounds were screened out based on the OPLS-DA modle. The application of GC-MS combined with chemometrics offers a theoretical framework for douchi quality control and classification. [ABSTRACT FROM AUTHOR]

Conifer needles are rich in resources and have essential ecological and biological functions. However, comparative analysis of the volatile components of immature and mature needles of the family Pinaceae has not been reported to date. In this study, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (GC-MS) was used to identify the volatile organic compounds (VOCs) in the immature and mature needles of five Pinaceae species. Altogether, 51 VOCs were identified, 31 of which reportedly show biological activity. The identified compounds include alcohols (6), terpenes (35), esters (7), and others (3). Terpenes were the major metabolites (78.38% to 97.18%) in the needles of the conifers. The needles were divided into four categories based on principal component analysis (PCA) and cluster analysis (CA). This is the first study to show a detailed examination of the differences in VOCs between immature and mature conifer needles. Furthermore, immature and mature needles of the five species were distinguished based on their specific VOCs. Our findings provide a reference for the utilization of conifer needles as valuable renewable resources. [ABSTRACT FROM AUTHOR]

The volatile components of nine commercial beers were characterized by headspace‐solid‐phase microextraction (HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC‐MS). Multivariate analysis was conducted to evaluate the similarities and differences between the volatile components and bioactive compounds present in the target beer samples. Thirty‐eight volatile compounds were identified, and their chemical categories were determined. Alcohols and esters were determined to be the predominant volatile components in samples. The differences and classifications of the beer samples were analysed through principal component analysis and cluster analysis. The analysis of the volatile compounds in beer samples revealed that the type and content of the volatiles can influence beer quality and taste. The combination of SPME‐GC‐MS and multivariate statistical analysis proves to be an effective approach for differentiating beer types and for allowing the quality control of beer. [ABSTRACT FROM AUTHOR]