Sequential ultrasound-microwave-assisted extraction of tuberose (Polianthes tuberosa L.) concrete: the effect of processing parameters on yield, volatile metabolite profiles, and functional groups. Biomass Conversion and Biorefinery

Abstract

Sequential ultrasound-microwave assisted extraction (UMAE) technique was performed to investigate the effect of solvent type (n-hexane, methanol and petroleum ether), size [cut flower (1.75 ± 0.26 cm) and whole flower (Tepal dimensions: length: 5.73 ± 0.27 and breadth: 4.17 ± 0.23 cm)], and soaking durations (0, 30, and 60 min) on the extraction yield of concrete from tuberose flowers. The optimized conditions were n-hexane, cut samples, and 30-min soaking duration, with an extraction yield of 95.04%. The tuberose concrete extracted by all three extraction methods with n-hexane as a solvent contained aroma compounds such as 1,8-cineole, methyl benzoate, indole, α-terpineol, trans-methyl isoeugenol, trans-farnesol, and benzyl benzoate. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectra of concretes extracted by different extraction methods with n-hexane solvent were notably similar in terms of apparent composition. Principal component analysis (PCA) and sparse partial least-squares discriminant analysis (sPLS-DA) could differentiate and separate the volatile organic compounds for the classification; however, sPLS-DA performed better than PCA.