Addition of Hop (Humulus Lupulus L.) Bitter Acids Yields Modification of Malt Protein Aggregate Profiles during Wort Boiling.

Hop bitter acids are used in the brewing industry to give beer bitterness. However, much of this bitterness is lost during processing, specifically during the wort boiling step. One of the major causes might be the interaction with protein-protein complexes. Therefore, the aim of this study was to clarify the role of hop bitter acids in protein aggregate formation using a proteomic approach. The effect of hop addition on protein composition was analyzed by liquid chromatography-mass spectrometry/MS (LC-MS/MS), and further analyses were performed to characterize the wort before and after boiling. Addition of hop bitter acids yielded a change in wort protein profiles, and hop bitter acids were found to bind primarily to less abundant proteins which are not related to beer quality traits, such as foam or haze. Wort protein aggregate profiles were revealed, and findings from this study suggested the precipitation of particular proteins in the aggregates during boiling when hops were added.

Anti-Inflammatory Markers of Hops Cultivars (Humulus lupulus L.) Evaluated by Untargeted Metabolomics Strategy.

Hops (Humulus lupulus L.) are edible flowers commonly used to add flavour and aroma to beer, besides they have rich chemical diversity and medicinal potential. In this work, an ex vivo anti-inflammatory assay via the LPS-induced signalling pathway and metabolomics approaches were performed to evaluate the ability of hops to inhibit the production of prostaglandin E2 (PGE2) inflammatory mediator and analyze which metabolites produced by the nine different hop cultivars are potential anti-inflammatory markers. Columbus, Chinook and Hallertau Mittelfrüh hop cultivars yielded extracts with PGE2 release inhibition rates of 86.7, 92.5 and 73.5 %, respectively. According to the multivariate statistical analysis, the majority of the metabolites correlated with the activity were prenylated phloroglucinol and phenolic homologs. These results suggest promissory anti-inflammatory hop metabolites.

Effects of dietary hop (Humulus lupulus L.) ß-acids on quality attributes, composition and oxidative stability of pork meat.

BACKGROUND: The effects of dietary levels of hop ß-acids on physical attributes, lipid oxidation and chemical composition of pork meat were evaluated. Thirty-two castrated male pigs obtained from a complete block design feeding experiment (6.23 ± 0.42 kg initial body weight (BW) to 20.45 ± 0.95 kg final BW) and fed diets supplemented with 0, 120, 240 or 360 mg kg-1 hop ß-acids during 35 days were slaughtered to sample longissimus dorsi muscle for meat analysis. RESULTS: No effects (P > 0.05) of dietary hop ß-acids were observed on meat physical attributes. Quadratic effects (P < 0.05) of hop ß-acids were observed on lipid and protein contents and on thiobarbituric acid-reactive substance (TBARS) values of meatballs, whose equations allowed the estimation of dietary hop ß-acid levels of 176, 169 and 181 mg kg-1 to provide up to 16.20% lipid reduction, 1.95% protein accretion and 23.31% TBARS reduction respectively. CONCLUSION: Dietary hop ß-acids fed to pigs might reduce lipid, increase protein and reduce lipid oxidation without affecting physical attributes of the pork meat. © 2017 Society of Chemical Industry.