Humulus lupulus and microbes: Exploring biotic causes for hop creep

Young, Jessica; Oakley, William R.M.; Fox, Glen

doi:10.1016/j.fm.2023.104298

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…cannot survive in hoppy beer due to high antimicrobial activity. Some modifications during fermentation can be implemented to maintain viability. , …”

Section: Detection and Prevention Of N-heterocyclesmentioning

confidence: 99%

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A Review of N-Heterocycles: Mousy Off-Flavor in Sour Beer

Martusevice,

Li,

Hengel

et al. 2024

J. Agric. Food Chem.

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Beer has over 600 flavor compounds and creates a positive tasting experience with acceptable sensory properties, which are essential for the best consumer experience. Spontaneous and mixed-culture fermentation beers, generally classified as sour beers, are gaining popularity compared to typical lager or ale styles, which have dominated in the USA for the last few decades. Unique and acceptable flavor compounds characterize sour beers, but some unfavorable aspects appear in conjunction. One such unfavorable flavor is called "mousy". This description is usually labeled as an unpleasant odor, identifying spoilage of fermented food and beverages. It is related as having the odor of mouse urine, cereal, corn tortilla chips, or freshly baked sour bread. The main compounds responsible for it are N-heterocyclic compounds: 2-acetyltetrahydropyridine, 2-acetyl-1-pyrroline, and 2-ethyltetrahydropyridine. The most common beverages associated with mousy off-flavor are identified in wines, sour beers, other grainbased beverages, and kombucha, which may contain heterofermentative lactic acid bacteria, acetic acid bacteria, and/or yeast/fungus cultures. In particular, the fungal species Brettanomyces bruxellensis are associated with mousy-off flavor occurrence in fermented beverages matrices. However, many factors for N-heterocycle formation are not well-understood. Currently, the research and development of mixed-cultured beer and non/low alcohol beverages (NABLAB) has increased to obtain the highest quality, sensory, functionality, and most notably safety standards, and also to meet consumers' demand for a balanced sourness in these beverages. This paper introduces mousy off-flavor expression in beers and beverages, which occurs in spontaneous or mixed-culture fermentations, with a focus on sour beers due to common inconsistency aspects in fermentation. We discuss and suggest possible pathways of mousy off-flavor development in the beer matrix, which also apply to other fermented beverages, including non/low alcohol drinks, e.g., kombucha and low/nonalcohol beers. Some precautions and modifications may prevent the occurrence of these off-flavor compounds in the beverage matrix: improving raw material quality, adjusting brewing processes, and using specific strains of yeast and bacteria that are less likely to produce the off-flavor. Conceivably, it is clear that spontaneous and mixed culture fermentation is gaining popularity in industrial, craft, and home brewing. The review discusses important elements to identify and understand metabolic pathways, following the prevention of spoilage targeted to off-flavor compounds development in beers and NABLABs.

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“…cannot survive in hoppy beer due to high antimicrobial activity. Some modifications during fermentation can be implemented to maintain viability. , …”

Section: Detection and Prevention Of N-heterocyclesmentioning

confidence: 99%

“…Some modifications during fermentation can be implemented to maintain viability. 37,131 Beer is one of the most consumed beverages in the world, and a balanced flavor profile is essential for the best consumer experience. Mousy off-flavor is a common challenge in sour beer types.…”

Section: Detection and Prevention Of N-heterocyclesmentioning

confidence: 99%

A Review of N-Heterocycles: Mousy Off-Flavor in Sour Beer

Martusevice,

Li,

Hengel

et al. 2024

J. Agric. Food Chem.

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“…[15,16,23] but, on the other hand, Penicillium spp. was isolated as a probable source of diastatic enzymes driving "hop creep" in dry-hopped beer [24,25]. After identification of the presence of Penicillium spp., there were no data on the presence of their mycotoxins in hops.…”

Section: Introductionmentioning

confidence: 99%

First Report on Mycotoxin Contamination of Hops (Humulus lupulus L.)

Dodlek Šarkanj,

Vahčić,

Markov

et al. 2024

Toxins

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The presence of mycotoxins and other toxic metabolites in hops (Humulus lupulus L.) was assessed for the first time. In total, 62 hop samples were sampled in craft breweries, and analyzed by a multi-toxin LS-MS/MS method. The study collected samples from craft breweries in all of the Croatian counties and statistically compared the results. Based on previous reports on Alternaria spp. and Fusarium spp. contamination of hops, the study confirmed the contamination of hops with these toxins. Alternaria toxins, particularly tenuazonic acid, were found in all tested samples, while Fusarium toxins, including deoxynivalenol, were present in 98% of samples. However, no Aspergillus or Penicillium metabolites were detected, indicating proper storage conditions. In addition to the Alternaria and Fusarium toxins, abscisic acid, a drought stress indicator in hops, was also detected, as well as several unspecific metabolites. The findings suggest the need for monitoring, risk assessment, and potential regulation of Alternaria and Fusarium toxins in hops to ensure the safety of hop usage in the brewing and pharmaceutical industries. Also, four local wild varieties were tested, with similar results to the commercial varieties for toxin contamination, but the statistically significant regional differences in toxin occurrence highlight the importance and need for targeted monitoring.

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