Microbial stabilization of craft beer by filtration through silica supports functionalized with essential oil components

Flavour Stability of a Cold-Stored Unpasteurized Low-Alcohol Beer Produced by Saccharomycodes ludwigii

Low-alcohol beer (LAB) is a growing part of the brewing industry in terms of market volumes and consumer interest. Universities and research centres are making efforts to improve organoleptic profile and flavour stability of the product. One of the main limitations of such products is the stability. These beers must be severely filtered and pasteurized, causing a significant loss of quality in terms of flavour. Herein, flavour stability of an unpasteurized and unfiltered LAB was checked during 120 days of cold storage (4 ± 1 °C). The results showed that the beer remained stable for 120 days for many observed parameters. The alcohol content increased from 0.5 to 0.7% v/v. The beer without oxygen was more stable than that filled with oxygen in the headspace. The results confirmed the possibility to produce an unpasteurized craft LAB by Saccharomycodes ludwigii by the cold chain.

Graphical Abstract

Consumer Preferences for Craft Beer by Means of Artificial Intelligence: Are Italian Producers Doing Well?

To identify the key drivers of consumption, we analyzed consumer preferences and estimated the willingness to pay for craft beer compared with industrial products in Italy. For this purpose, we conducted an ad hoc survey of 469 craft beer drinkers and set up an econometric strategy using a machine learning estimation technique. The main results show that young consumers, the ability to perceive and evaluate quality, and the frequency of consumption are the main profile elements that, more than others, orient preferences. In the meantime, sustaining local beer producers, sharing good time with friends, and the perception of beer as healthier compared with other drinks are also important. The most preferable product attributes are can packaging and the search for unique taste.

A comprehensive review of the benefits of drinking craft beer: Role of phenolic content in health and possible potential of the alcoholic fraction

Currently, there is greater production and consumption of craft beer due to its appreciated sensory characteristics. Unlike conventional beer, craft beers provide better health benefits due to their varied and high content of phenolic compounds (PCs) and also due to their alcohol content, but the latter is controversial. The purpose of this paper was to report on the alcoholic fraction and PCs present in craft beers and their influence on health. Despite the craft beer boom, there are few studies on the topic; there is a lot of field to explore. The countries with the most research are the United States > Italy > Brazil > United Kingdom > Spain. The type and amount of PCs in craft beers depends on the ingredients and strains used, as well as the brewing process. It was determined that it is healthier to be a moderate consumer of alcohol than to be a teetotaler or heavy drinker. Thus, studies in vitro, with animal models and clinical trials on cardiovascular and neurodegenerative diseases, cancer, diabetes and obesity, osteoporosis and even the immune system suggest the consumption of craft beer. However, more studies with more robust designs are required to obtain more generalizable and conclusive results. Finally, some challenges in the production of craft beer were detailed and some alternative solutions were mentioned.

Effects of Botanical Ingredients Addition on the Bioactive Compounds and Quality of Non-Alcoholic and Craft Beer

Special beers, known as artisanal, are progressively gaining consumer preference, opening up competition, and acquiring more space in the market. Considering that, exploration for new formulations is justified and plants represent a source of novel compounds with promising antioxidant activity for this beer segment. This paper aims to evaluate the current knowledge on the role of botanical ingredients on the final yield of bioactive compounds in special beer, and how these molecules generally affect the sensory profile. Furthermore, the estimated difficulties of implementation, taking into account the new processes and the relative cost, are discussed. The addition of plants to beer could serve the interests of both the industry and consumers, on one hand, by improving the functional properties and offering a unique flavor, and on the other hand by adding variety to the craft beer landscape. This paper provides guidance and future directions for the development of new products to boost the brewing industry. Brewing processes might affect the valuable compounds, especially the phenolic content. Consequently, future studies need to identify new methods for protecting the level of bioactive compounds in special beer and increasing the bio-accessibility, along with optimization of the sensory and technological properties.

In vitro toxicological evaluation of mesoporous silica microparticles functionalised with carvacrol and thymol

The cytotoxicity of carvacrol- and thymol-functionalised mesoporous silica microparticles (MCM-41) was assessed in the human hepatocarcinoma cell line (HepG2). Cell viability, lactate dehydrogenase (LDH) activity, reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm), lipid peroxidation (LPO) and apoptosis/necrosis analyses were used as endpoints. The results showed that both materials induced cytotoxicity in a time- and concentration-dependent manner, and were more cytotoxic than free essential oil components and bare MCM-41. This effect was caused by cell-particle interactions and not by degradation products released to the culture media, as demonstrated in the extract dilution assays. LDH release was a less sensitive endpoint than the MTT (thiazolyl blue tetrazolium bromide) assay, which suggests the impairment of the mitochondrial function as the primary cytotoxic mechanism. In vitro tests on specialised cell functions showed that exposure to sublethal concentrations of these materials did not induce ROS formation during 2 h of exposure, but produced LPO and ΔΨm alterations in a concentration-dependent manner when cells were exposed for 24 h. The obtained results generally support the hypothesis that the carvacrol- and thymol-functionalised MCM-41 microparticles induced toxicity in HepG2 cells by an oxidative stress-related mechanism that resulted in apoptosis through the mitochondrial pathway.

Efficient reduction in vegetative cells and spores of Bacillus subtilis by essential oil components-coated silica filtering materials

Inactivation of bacterial spores is a key objective for developing novel food preservation technologies. In this work, the removal properties of filtering materials based on silica microparticles functionalized with essential oil components (EOCs) (carvacrol, eugenol, thymol, and vanillin) against Bacillus subtilis, a spore-forming bacterium, in two liquid matrices were investigated. The viability of vegetative cells and spores after treatment was also evaluated. The results exhibited marked removal effectiveness against B. subtilis vegetative cells and spores after filtration with the different silica supports coated with EOCs in either sterile water or nutrient broth, with reductions of 3.2 to 4.9 log units and 3.7 to 5.0 log units for vegetative cells and spores, respectively. The fluorescent viability images revealed the poor viability of the treated B. subtilis vegetative cells and spores due to damage to the cell envelope when coming into contact with the immobilized antimicrobials. The culture counts results revealed the great inhibitory capacity of the EOC-functionalized silica microparticles against B. subtilis vegetative cells and spores after a single filtration. Hence, the present work suggests the feasibility of using EOC-functionalized supports as filtering aids to enhance the microbial quality of liquid matrices with spore-forming microorganisms. PRACTICAL APPLICATION: The developed antimicrobial-coated filters have shown remarkable removal properties against an important spore-forming bacterium in food industry. These filters may be used as a potential sterilization technique for preservation of different beverages alone or in combination with other mild-thermal or nonthermal techniques.

Comparative cytotoxic study of silica materials functionalised with essential oil components in HepG2 cells

This work evaluated the cytotoxic effect of different EOCs-functionalised silica particle types. The in vitro toxicity of eugenol and vanillin-immobilised SAS, MCM-41 microparticles and MCM-41 nanoparticles was evaluated on HepG2 cells, and compared to free EOCs and pristine materials. The results revealed that free essential oil components and bare silica had a mild cytotoxic effect on HepG2 cells. However, the comparative study showed that free eugenol and vanillin had a milder cytotoxic effect than the equivalent concentrations of immobilised components on the different silica particles, while differences in cell viability between the bare and functionalised particles relied on the type of analysed material. The most cytotoxic materials were eugenol and vanillin-functionalised MCM-41 micro with IC₅₀ values of 0.19 and 0.17 mg/mL, respectively, at 48 h exposure. Differences in cytotoxicity between functionalised particles may be attributed to the density of the functional components on their surface as a result of the functionalisation reaction performance for different materials. The study of the physico-chemical properties of particles demonstrated that cationic nature and increased hydrophobicity could be responsible for promoting cell-particle interactions for the eugenol and vanillin functionalised silica particles, enhancing their cytotoxic behaviour.