Changes in the composition of hop secondary metabolites induced by high hydrostatic pressure

Abstract

Hops contain large amounts of secondary metabolites, many of which have notable bioactive and sensory characteristics. Many of these properties are affected by the processing of raw hops into products. We studied the influence of high‐pressure processing (HPP) on the content and composition of secondary metabolites in hop homogenates prepared from fresh green cones of several Czech hop varieties. Homogenates contained more hop oils (27% on average) compared to dried hops. The composition of essential oils in homogenates after HPP showed a decrease in fatty acid methyl and thioesters fractions (80 and 100% respectively). Conversely, the number of other bioactive compounds from the group of resins and prenylflavonoids that remained in HPP homogenates was retained to a greater extent than in the dried hops. Low temperatures and an oxygen‐free atmosphere were effective conditions for the preservation of raw hops and hop products. Copyright © 2018 The Institute of Brewing & Distilling

Conventional and innovative extraction technologies to produce food‐grade hop extracts: Influence on bitter acids content and volatile organic compounds profile

“…HHP extraction, compared with all other techniques, allowed to extract a limited number of VOCs (18 out of 34 compounds). Since other authors (Krofta et al, 2018) investigating the volatile profile of fresh hops homogenates subjected to high hydrostatic pressure processes did not find any loss of VOCs, this result highlights the lower capability of HHP at the conditions applied in this study to extract these volatile secondary metabolites.…”

“…Hop cones, the female inflorescences of Humulus lupulus L., are known worldwide as the main ingredient in the production of beer, which confer the essential character of bitterness and the overall flavor including the typical “spicy” or “hoppy” aroma (De Keukeleire et al., 2003; Krofta et al., 2018).…”

“…The second class (up to 30%) is formed during the ripening, processing, and storage of hops and includes linalool, geraniol, caryophyllene oxide, and farnesol. The third class represents a minor part of the volatile fraction (<1%) and comprises compounds (e.g., hydrogen sulfide, dimethyl sulfide with a very low odor threshold) (Karabín et al., 2016; Krofta et al., 2018; Pistelli et al., 2018).…”

Using Plant-Based Preparations to Protect Common Bean against Halo Blight Disease: The Potential of Nettle to Trigger the Immune System

“…The results showed an inhibitory potential of all PBPs in a concentration-dependent manner (Figure 3). R H -PBP was obtained from female hop cones which accumulate a great amount of secondary metabolites such as xanthohumol and other derivatives, with strong antimicrobial activity against anaerobic or ruminal bacteria [49,50]. In this line, equisetum (E-PBP in this study) has shown antibiotic activity against some Gram-positive bacteria and oomycetes [51,52].…”

Effect of Salt Content Reduction on Food Processing Technology

“…It is possible to prepare a homogeneous mass by mixing the fresh plants, treat this mass with high pressure and then use it as a semi-finished product in various dishes [ 54 , 55 ]. The herbs homogenate preparations represent a proven method of fresh herbs processing without heating or freezing and a method when biologically active substances are preserved [ 56 ].…”