Effect of Addition of Different Phenolic-Rich Extracts on Beer Flavour Stability

Preliminary research on the flavor substance and antioxidant capacity of beers produced with baking Qingke

The addition of baked Qingke improves the flavor profile of beer. In this study, beer was brewed using Qingke baked at various temperatures. The beer produced with Qingke baked at 180 °C achieved the highest sensory score (40/50), an alcohol content of 6.92% (v/v), a total phenolic content of 446.42 mg/L, melanoidin concentration of 98.22 g/L, a color value of 10.88 EBC, and exhibited satisfactory antioxidant activity. Analysis of volatile compounds using HS-SPME-GC-MS revealed 48 compounds, of which esters accounted for 63% and alcohols accounted for 27% of the total content. The flavor profile of the beer varied across different baking temperatures. Pyrazines and aldehydes were predominantly present in samples baked at higher temperatures (T3, T4, and T5). Correlation analysis showed that the baking flavor in the beer was primarily correlated with 2, 5-dimethyl-pyrazine, trimethyl-pyrazine, phenylacetaldehyde, and ethyl 9-decenoate (R > 0.9).

Comparative Study of Condensed and Hydrolysable Tannins during the Early Stages of Zebrafish Development

In this study, we present data on the effects of condensed tannins (CTs) and hydrolysable tannins (HTs), polyphenols extracted from plants, at different concentrations on zebrafish development to identify the range of concentrations with toxic effects. Zebrafish embryos were exposed to CTs and HTs at two different concentration ranges (5.0-20.0 μgL-1 and 5.0-20.0 mgL-1) for 72 h. The toxicity parameters were observed up to 72 h of treatment. The uptake of CTs and HTs by the zebrafish larvae was assessed via HPLC analysis. A qRT-PCR analysis was performed to evaluate the expressions of genes cd63, zhe1, and klf4, involved in the hatching process of zebrafish. CTs and HTs at 5.0, 10.0, and 20.0 μgL-1 were not toxic. On the contrary, at 5.0, 10.0, and 20.0 mgL-1, HTs induced a delay in hatching starting from 48 h of treatment, while CTs showed a delay in hatching mainly at 48 h. The analysis of gene expression showed a downregulation in the group exposed to HTs, confirming the hatching data. We believe that this study is important for defining the optimal doses of CTs and HTs to be employed in different application fields such as the chemical industry, the animal feed industry, and medical science.

Effects of tea addition on antioxidant capacity, volatiles, and sensory quality of beer

Green tea has great potential to enhance the quality of beer. In this study, green tea was added at different stages of beer brewing, and evaluated the antioxidant capacity, volatile components, as well as sensory quality. The results showed that the addition of green tea during the start of boiling has great potential for application, and the green tea beer (GTB) had remarkable antioxidant properties (ABTS radical scavenging ability, 8.67 mmol TE/L; DPPH radical scavenging ability, 3.97 mmol TE/L; reducing power, 3.28 mmol TE/L), and an excellent sensory quality (acceptance, 6.09/9). HPLC analysis indicated that the principal phenolics in GTB were catechin and caffeic acid, in addition, the relative amounts of ferulic acid, gallic acid can be used to differentiate between GTB and beer. HS-SPME-GC-MS analyses showed that ethyl caprylate, ethyl nonanoate, ethyl caprate, linalool, and phenethyl alcohol were potentially significant for the aroma profile of GTB.

Effect of mashing temperature on fermentation and antioxidant capacity of Qingke wort

Background and Objectives

Mashing temperature is important during beer brewing processes. Qingke malt was a new material whose application in the beer industry holds significant importance for the beer industry and agriculture development in the Qinghai–Tibet Plateau. The objective of this study was to investigate the effects of mashing temperature on the physicochemical parameters, fermentation capacity, and antioxidant capacity of Qingke wort.

Findings

Ethanol production and the real degree of fermentation decreased with increasing the temperature—S, while the real extract increased with increasing the temperature—S. A lower temperature—S proved to be more advantageous for the fermentation capacity of Qingke wort. In addition, a positive correlation between reducing power and the temperature—P and a negative correlation between the 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonate) free radical scavenging activity and the temperature—S were found.

Conclusion

The fermentation capacity of Qingke wort was obtained the best when the temperature—P was 50°C and the temperature—S was 60°C. The antioxidant capacity of Qingke wort was satisfactory; the best was obtained when the temperature—P was 45°C and the temperature—S was 60°C.

Significance and Novelty

This is the first study to investigate the mashing characteristics of Qingke wort under different mashing temperatures. The results show that β‐glucan content was abundant in Qingke wort and was positively correlative with the temperature—S.

Polyphenol Composition by HPLC-DAD-(ESI-)MS/MS and Bioactivities of Extracts from Grape Agri-Food Wastes

BACKGROUND

Grape agri-food wastes, such as skin, seeds, and other discarded by-products, contain phytochemical compounds that offer potential health benefits.

METHODS

This study aimed to investigate the polyphenol composition and bioactivities of different extracts obtained from grape marc and seeds, with the goal of exploring their potential for application as natural food additives.

RESULTS

Regardless of the extraction method used (dynamic maceration, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE)), all extracts exhibited relatively high concentrations of phenolic compounds. The chemical characterization of the extracts revealed the presence of specific compounds and chemical groups associated with each extraction methodology. Moreover, the extracts displayed satisfactory antioxidant activities, especially in inhibiting lipoperoxidation as assessed by the TBARS assay. Additionally, the extracts demonstrated effective inhibition against different strains of bacteria and fungi known as food contaminants. Taken together, these findings indicate that those extracts have the potential to be tested as natural antioxidants and preservatives with sustainable origins in food and beverage systems. Among the extraction methods evaluated, traditional maceration and UAE provided extracts with the highest antioxidant and antimicrobial activities.

CONCLUSIONS

Our results suggest the opportunity to explore grape marc and seeds discarded by the winery industry in Portugal as natural sources of bioactive compounds, which could be employed as functional food ingredients or technological additives. The valorization of grape biowastes offers a promising strategy to reduce waste and harness their potential health benefits.

Evaluation of the antioxidant characteristics of craft beer with green tea

The addition of green tea as antioxidants to beer can improve the beer's flavor stability by protecting against staling during storage. To analyze the effect of different green teas on the flavor stability of beer, we developed an approach to rapidly evaluate their antioxidant activity. Ten types of craft beer were produced by adding different kinds of green tea during brewing, and their antioxidant activity and phenolic profiles were evaluated. The results showed remarkable variations in antioxidant activity and antioxidative compound contents, which were considerably higher in green tea beers than in non-tea beer (p < 0.05). A comprehensive evaluation function was developed to evaluate the total antioxidant activity of beers using principal component analysis. The highest total antioxidant activity was observed in Taiping Houkui beer, with a comprehensive evaluation score of 2.53. Pearson correlation analysis suggested that (-)-epigallocatechin gallate, (-)-epicatechin gallate, and (-)-epigallocatechin were strongly correlated with the total antioxidant activity of green tea beers (p < 0.01). The summation of their contents represented more than 60% of the total phenolic content of the teas, which can be used to predict the total antioxidant activity of green tea beers. PRACTICAL APPLICATION: Flavor stability is of prime concern for brewers, and flavor aging is increasingly becoming the limiting factor in beer shelf life. The application of green tea as antioxidants in beer can improve the flavor stability by protecting against beer staling during storage. The analytical method developed in this study will contribute to the rapid comparison of the effect of different green teas on the flavor stability of beer. Furthermore, the research findings demonstrate the potential benefits of green teas to beer flavor stability, which is of considerable importance in promoting the development and consumption of green teas.

Adding functional properties to beer with jasmine tea extract

Hops provide the characteristic bitter taste and attractive aroma to beer; in this study, hops were replaced by jasmine tea extract (JTE) during late-hopping. The addition of JTE improved the beer foam stability 1.52-fold, and increased the polyphenol and organic acid contents. Linalool was the most important aroma compound in hopped (HOPB) and jasmine tea beer (JTB), but other flavor components were markedly different, including dimeric catechins, flavone/flavonol glycosides, and bitter acids and derivatives. Sensory evaluation indicated that addition of JTE increased the floral and fresh-scent aromas, reduced bitterness and improved the organoleptic quality of the beer. The antioxidant capacity of JTB was much higher than that of HOPB. The inhibition of amylase activity by JTB was 30.5% higher than that of HOPB. Functional properties to beer were added by substituting jasmine tea extract for hops during late hopping.

From the Raw Materials to the Bottled Product: Influence of the Entire Production Process on the Organoleptic Profile of Industrial Beers

In the past few years, there has been a growing demand by consumers for more complex beers with distinctive organoleptic profiles. The yeast, raw material (barley or other cereals), hops, and water used add to the major processing stages involved in the brewing process, including malting, mashing, boiling, fermentation, and aging, to significantly determine the sensory profile of the final product. Recent literature on this subject has paid special attention to the impact attributable to the processing conditions and to the fermentation yeast strains used on the aromatic compounds that are found in consumer-ready beers. However, no review papers are available on the specific influence of each of the factors that may affect beer organoleptic characteristics. This review, therefore, focuses on the effect that raw material, as well as the rest of the processes other than alcoholic fermentation, have on the organoleptic profile of beers. Such effect may alter beer aromatic compounds, foaming head, taste, or mouthfeel, among other things. Moreover, the presence of spoilage microorganisms that might lead to consumers’ rejection because of their impact on the beers’ sensory properties has also been investigated.

Regulation of Plant Tannin Synthesis in Crop Species

Plant tannins belong to the antioxidant compound family, which includes chemicals responsible for protecting biological structures from the harmful effects of oxidative stress. A wide range of plants and crops are rich in antioxidant compounds, offering resistance to biotic, mainly against pathogens and herbivores, and abiotic stresses, such as light and wound stresses. These compounds are also related to human health benefits, offering protective effects against cardiovascular and neurodegenerative diseases in addition to providing anti-tumor, anti-inflammatory, and anti-bacterial characteristics. Most of these compounds are structurally and biosynthetically related, being synthesized through the shikimate-phenylpropanoid pathways, offering several classes of plant antioxidants: flavonoids, anthocyanins, and tannins. Tannins are divided into two major classes: condensed tannins or proanthocyanidins and hydrolysable tannins. Hydrolysable tannin synthesis branches directly from the shikimate pathway, while condensed tannins are derived from the flavonoid pathway, one of the branches of the phenylpropanoid pathway. Both types of tannins have been proposed as important molecules for taste perception of many fruits and beverages, especially wine, besides their well-known roles in plant defense and human health. Regulation at the gene level, biosynthesis and degradation have been extensively studied in condensed tannins in crops like grapevine (Vitis vinifera), persimmon (Diospyros kaki) and several berry species due to their high tannin content and their importance in the food and beverage industry. On the other hand, much less information is available regarding hydrolysable tannins, although some key aspects of their biosynthesis and regulation have been recently discovered. Here, we review recent findings about tannin metabolism, information that could be of high importance for crop breeding programs to obtain varieties with enhanced nutritional characteristics.

Modeling in Brewing—A Review

Beer production has over a thousand-year tradition, but its development in the present continues with the introduction of new technological and technical solutions. The methods for modeling and optimization in beer production through an applied analytical approach have been discussed in the present paper. For this purpose, the parameters that are essential for the main processes in beer production have been considered—development of malt blends, guaranteeing the main brewing characteristics; obtaining wort through the processes of mashing, lautering and boiling of wort; fermentation and maturation of beer. Data on the mathematical dependences used to describe the different stages of beer production (one-factor experiments, modeling of mixtures, experiment planning, description of the kinetics of microbial growth, etc.) and their limits have been presented, and specific research results of various authors teams working in this field have been cited. The independent variables as well as the objective functions for each stage have been defined. Some new trends in the field of beer production have been considered and possible approaches for their modeling and optimization have been highlighted. The paper suggests a generalized approach to describe the main methods of modeling and optimization, which does not depend on the beer type produced. The proposed approaches can be used to model and optimize the production of different beer types, and the conditions for their application should be consistent with the technological regimes used in each case. The approaches for modeling and optimization of the individual processes have been supported by mathematical dependencies most typical for these stages. Depending on the specific regimes and objectives of the study, these dependencies can be adapted and/or combined into more general mathematical models. Some new trends in the field of beer production have been considered and possible approaches for their modeling and optimization have been highlighted.

Biopreservation of beer: Potential and constraints

The biopreservation of beer, using only antimicrobial agents of natural origin to ensure microbiological stability, is of great scientific and commercial interest. This review article highlights progress in the biological preservation of beer. It describes the antimicrobial properties of beer components and microbiological spoilage risks. It discusses novel biological methods for enhancing beer stability, using natural antimicrobials from microorganisms, plants, and animals to preserve beer, including legal restrictions. The future of beer preservation will involve the skilled knowledge-based exploitation of naturally occurring components in beer, supplementation with generally regarded as safe antimicrobial additives, and mild physical treatments.

Profiling of Phenolic Compounds of Fruit Peels of Different Ecotype Bananas Derived from Domestic and Imported Cultivars with Different Maturity

Banana is one of the most produced and consumed fruits in the world and its fruit peel accounts for about 40% of the total fresh quantity of ripe fruit, which is usually regarded as waste and poses serious environmental hazards. However, it is a promising source of natural bioactive compounds including phenolic compounds. Determination of the phenolic compounds in fruit peel from different cultivars and subgroups over a range of maturities provides convincing information for making full use of them. This study developed a sensitive and reliable analytical method—ultra-high performance liquid chromatography—coupled with electrospray ionization tandem mass spectrometry (UPLC-MS/MS) for measuring phenolic compounds in fruit peel from different ecotype cultivars and subgroups with different maturity. The results showed that quinic acid had the highest concentration ratio among the main phenolic compounds in the green/ripe peel of all banana cultivars; among all banana cultivars, the total phenolic compound contents of green banana peel were significantly higher than that of ripe banana peel; the total phenolic compound contents in the green/ripe fruit peel of non-dessert bananas were significantly higher than that of dessert bananas (green: non-dessert banana 1.48 ± 0.44 mg/g vs. dessert banana 0.97 ± 0.12 mg/g; ripe: non-dessert banana 0.26 ± 0.13 mg/g vs. dessert banana 0.19 ± 0.06 mg/g). These data provide a basis for the rational utilization of phenolic compound extractions from banana peel with huge biomass in the next step.