Evaluation of prenylflavonoids and hop bitter acids in surplus yeast
This study developed a high performance liquid chromatography with diode array detection (HPLC–DAD) and tandem mass spectrometry (MS–MS) method for determination of prenylflavonoids and hop bitter acids in surplus yeast, a byproduct from beer brewing process. This method enabled the simultaneous separation of 4 prenylflavonoids and 20 hop bitter acids within 30 min by employing a Hypersil-Keystone HyPURITY C18 column and a gradient mobile phase composed of phosphoric acid aqueous solution at pH 1.6 and acetonitrile. For HPLC–DAD analysis, the limits of detection and limits of quantitation ranged from 0.04 to 0.15 µg/mL and from 0.12 to 0.45 µg/mL, respectively, and the recoveries ranged from 82.6 to 99.7%. The intra-day variability and inter-day variability ranged from 1.37 to 8.82% and from 0.68 to 9.74%, respectively. For qualitation by MS–MS, the positive mode was discovered to possess satisfactory collision capacity and high sensitivity for prenylflavonoids, while the negative mode was more suitable for the ionization of hop bitter acids. The content of hop bitter acids in surplus yeast were higher than that of prenylflavonoids, and isomers and oxidation products of hop bitter acids were found. This study has advantages in identifying more components, short separation time, satisfactory resolution, high accuracy and high precision.
KeywordsPrenylflavonoids Hop bitter acids Surplus yeast Brewing byproducts HPLC–DAD Tandem mass spectrometry
This study was supported by a Grant (MOST 103–2221-E-030–014) from the Ministry of Science and Technology, Taiwan.
- García-villalba R, Cortacero-ramírez S, Segura-carretero A, Martín-lagos JA, Fernnández-gutiérrez A (2006) Analysis of hop acids and their oxidized derivatives and iso-α-acids in beer by capillary electrophoresis-electrospray ionization mass spectrometry. J Agric Food Chem 54:5400–5409CrossRefGoogle Scholar
- Hofte AJP, Hoeven RAM (1998) Characterization of hop acids by liquid chromatography with negative electrospray ionization mass spectrometry. J Am Soc Brew Chem 56:118–122Google Scholar
- Mussatto SI (2007) Biotechnological potential of brewing industry by-products. In: Nigam PS, Pandey A (eds) Biotechnology for agro-industrialresidues utilization. Springer, Cham, pp 313–326Google Scholar
- SAS (2016) SAS Procedures and SAS/Graph User’s Guide, version 9.4. SAS Institute, Inc., CaryGoogle Scholar
- Siegel L, Miternique-Grosse A, Griffon C, Klein-Soyer C, Lobstein A, Raul F, Stephan D (2008) Antiangiogenic properties of lupulone, a Bitter acid of hop cones. Anticancer Res 28:289–294Google Scholar
- Wilhelm H, Wessjohann LA (2006) An efficient synthesis of the phytoestrogen 8-prenylnaringenin from xanthohumol by a novel demethylation process. Tetrahedron 3:213–232Google Scholar
- Yajima H, Ikeshima E, Shiraki M, Kanaya T, Fujiwara D, Odai H, Tsuboyama-Kasaoka N, Ezaki O, Oikawa S, Kondo K (2004) Isohumulones, bitter acids derived from hops, activate both peroxisome proliferator-activated receptor α and γ and reduce insulin resistance. J Biol Chem 279:33456–33462CrossRefGoogle Scholar