Evaluation of prenylflavonoids and hop bitter acids in surplus yeast

• Published in: Journal of food science and technology Vol. 56; no. 4; pp. 1939 - 1953
• Main Authors: Hsu, Ying-Yu, Kao, Tsai-Hua
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.04.2019; Springer Nature B.V
• Subjects: Acetonitrile; Acids; Aqueous solutions; Beer; Bitter acids; Breweries; Brewing; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Food Science; High performance liquid chromatography; Ionization; Ions; Isomers; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Nutrition; Original; Original Article; Oxidation; Phosphoric acid; Prenylflavonoids; Quantitation; Separation; Variability; Yeast; Prenylflavonoids; Tandem mass spectrometry; Hop bitter acids; Brewing byproducts; Surplus yeast; HPLC–DAD
• ISSN: 0022-1155; 0975-8402
• DOI: 10.1007/s13197-019-03660-6

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.