High hydrostatic pressure treatments enhance volatile components of pre-germinated brown rice revealed by aromatic fingerprinting based on HS-SPME/GC-MS and chemometric methods.

Germination favors to significantly enhance functional components and health attributes of whole-grain brown rice (BR), but the production of germinated BR (GBR) compromises the typical rice flavor perception due to soaking process. Simultaneously, high hydrostatic pressure (HHP) is considered as an effective processing technique to enhance micronutrients utilization efficiency of GBR and improve products flavor, but no information about the effects of HHP treatments on volatile fingerprinting of GBR has been reported. Therefore, the objective of this work was to apply HHP to improve the flavor and odor of GBR grains by exploring HHP-induced changes in aroma compounds. GBR grains were obtained by incubating at 37°C for 36h, and subsequently subjected to HHP treatments at pressures 100, 300 and 500MPa for 15min, using 0.1MPa as control. Headspace solid-phase micro extraction coupled to gas chromatography mass spectrometry was used to characterize process-induced shifts of volatile organic compounds fingerprinting, followed by multivariate analysis. Our results confirmed the significant reduction of total volatile fractions derived from germination process. Contrarily, the following HHP treatments greatly enhanced the flavor components of GBR, particularly characteristic odorants including aldehydes, ketones, and alcohols. Principal component analysis further indicated the different influence of germination and high pressure on the changes in volatile components. Partial least square-discrimination analysis suggested that 4-vinylguaiacol was closely linked to germination, whereas E,E-2,4-decadienal, E-2-hexenal, E,E-2,4-heptadienal and benzyl alcohol could be considered as volatile biomarkers of high pressure.