Pulsed Electric Field continuous pasteurization of different types of beers

Thermal pasteurization of bottled beer is used to extend its shelf life. However, the thermal process negatively affects the beer sensory. In this research, beer was processed using Pulsed Electric Fields (PEF), a non-thermal continuous preservation technology that has the potential to be implemented at a commercial scale by the brewing industry. The main goal of this work was to investigate the feasibility of PEF for yeast inactivation and its impact on beer sensory.First, the effect of a PEF process (temperature below 43 °C, 45 kV/cm electrical field intensity, 46 pulses, 70 μs) on Saccharomyces cerevisiae ascospores inactivation in nine different beers comprising ale, lager, dark, low alcohol, and no alcohol, was investigated. Log reductions of 0.2 and 2.2 were registered for 0 and 7% alc/vol beers, respectively, which indicated that the alcohol content is the major beer constituent driving the microbial inactivation. Then, 0, 4, and 7% alc/vol beers containing S. cerevisiae ascospores were submitted to PEF combined with thermal processing up to 53 °C. An increase in the PEF treatment temperature from 43 to 53 °C caused at least an additional 0.7, 2.1 and 1.8 log reductions in the yeast spore population for 0, 4, and 7% alc/vol beers, respectively. Results of another experiment carried out with 4 and 7% alc/vol beers, showed the huge advantage of using PEF compared with thermal processing. Additionally, lightstruck attribute sensory tests revealed six (aroma) and three (flavour) PEF beers did not develop the lightstruck character, being acceptable in terms of sensory. The results of this study can be helpful for designing appropriate PEF conditions to pasteurize beers with different alcohol contents.     

Investigation of the geographical provenance of the beer available in South Korea using multielements and isotopes

Although beer has the largest share of the global alcoholic beverage market, only limited studies of beer have been performed in terms of elemental and isotopic compositions. Here, we measured elemental and isotopic compositions—including carbon and oxygen isotopes as well as ⁸⁷Sr/⁸⁶Sr ratios—of beers available in South Korea to examine geographical differences. Although most of the elements analyzed in this study were not markedly different between the beer samples, there was a clear distinction in the isotopic compositions of the samples. δ¹³C_DIC values indicated that most of the beer samples were produced from C₃ plants, such as barley or wheat. δ¹⁸O values allowed the samples to be discriminated by latitude, reflecting a negative correlation between latitude and isotopic composition. Similarly, ⁸⁷Sr/⁸⁶Sr ratios were different between the samples due to the bedrock. Statistical analysis of the combination of elemental and isotopic compositions showed a clear difference between the beer samples according to the geographical provenance on a continental scale. This study demonstrated a powerful method for distinguishing diverse beers according to their geographical provenance, and will make an important contribution to research into discrimination of the geographical origin of diverse processed foods available commercially.     

Deoxynivalenol and zearalenone occurence in beers analysed by an enzyme-linked immunosorbent assay method

The occurrence of deoxynivalenol and zearalenone in samples of 91 beers commercialised in Poland was the topic of investigation. Most of beers were produced by domestic companies. The analysis was conducted using the enzyme-linked immunosorbent assay method (ELISA). Deoxynivalenol has been found in 100% and zearalenone in 11% of tested beer samples, with ranges of 6–70.2 μg/L and 0–0.546 μg/L, respectively. The mean levels of 20.66 μg/L for deoxynivalenol and 0.044 μg/L for zearalenone contribute on average of 8.6% and 0.04% of the estimated tolerable daily intake of both mycotoxins, considering an average daily intake of 0.25 l of beer per capita in Poland. The concentration of deoxynivalenol was found to be slightly higher in top-fermented beers. The deoxynivalenol content was also higher in dark-coloured beers both in the top-fermented and bottom-fermented beer samples. The regression analysis showed very little correlation between deoxynivalenol content and alcohol percentages by volume.     

Processing factors of triadimefon and triadimenol in barley brewing based on response surface methodology

Numerous studies have focused on the effects of food-processing techniques on pesticide residues. However, it remains a challenge to ensure high-quality processing and effective pesticide removal from foods. Triadimefon (TF) is a broad-spectrum fungicide that is widely used in barley crop, and its residues are detected in its products, including beer. In this study, we investigated the dissipation kinetics of TF during fermentation mediated by two different yeast strains, Saccharomyces cerevisiae IAPPST 1401 (Y1) and CICC 1202 (Y2), and found that Y2 promoted the degradation of TF. Response surface methodology was used to optimize fermentation process variables, in order to achieve the maximum removal rate of TF and the minimum production of its corresponding metabolite, triadimenol (TN). Processing factors (PFs) were also evaluated during the optimized brewing process and were close to 1 for TF during the malting, milling, boiling, and cooling steps, but not in mashing and fermentation that were 0.19 and 0.13, respectively. TF degraded to TN during brewing, and a PF value of >1 for TN was also observed in malting and fermentation. Our analysis concluded that beers produced using the yeasts and brewing methods we investigated are safe for human consumption.     

Aflatoxin contamination in unrecorded beers from Kenya – A health risk beyond ethanol

Samples of unrecorded opaque beers (n = 58; 40 based on maize, 5 on sorghum and 13 on other plants) and recorded wines (n = 8) in Kenya were screened for aflatoxins using a rapid ELISA technique followed by confirmation using liquid chromatography-tandem mass spectrometry. Six of the maize beers were obtained from Kibera slums in Nairobi County. Aflatoxin contamination was detected in six unrecorded beers (10%), but in none of the recorded wines. Remarkably, three of the aflatoxin positive samples were from the Kibera slums.The mean concentration of aflatoxins in the positive samples was 3.5 μg/L (range 1.8–6.8 μg/L), corresponding for an average consumption of 500 mL (1 standard drink) to a margin of exposure (MOE) of 36 (range: 15–58), which is considered as ‘risk’. On the other hand, the alcoholic strength of the aflatoxin positive samples had a mean of 4.3% vol (range 3.5–4.8%) corresponding to a MOE of 2.5 (range of 2.2–3.0) for the equivalent consumption volume. While aflatoxins pose a risk to the consumer, this risk is about 10 times lower than the risk of ethanol.The Joint FAO/WHO Expert Committee on Food Additives sets no acceptable daily intake for aflatoxins since they are genotoxic carcinogens and instead recommends for the reduction of aflatoxin dietary exposure as an important public health goal, particularly in populations who consume high levels of any potentially aflatoxins-contaminated food. Nevertheless, ethanol still posed a considerably higher risk in the unrecorded beers examined. However, consumers should be informed about aflatoxins, as these are an involuntary and unknown risk to them. In addition, producers should be educated about measures to reduce aflatoxins in alcoholic beverages.     

Pulsed electric field technology in the manufacturing processes of wine,beer, and rice wine: A review

Pulsed electric field (PEF) technology is an alternative to traditional food processing because this application can ensure good product quality and energy use efficiency. In PEF applications, the functional compounds extracted from food products can be enhanced, and the microorganisms contaminating the food products during processing can be inactivated. These properties are considered advantageous by alcoholic beverage producers. In this review, studies on the PEF treatment of wine, beer, and rice wine are summarized. The PEF technology is used in the pretreatment in grape wine and control of microbial growth in grape wine, beer, and rice wine. In grape wines, the PEF pretreatment can increase phenolic compound and anthocyanin contents and can enhance color intensity; this pretreatment slightly influences the organoleptic characteristics of samples. The PEF technology is also an effective tool to sterilize grape wine, beer, and rice wine. With this application, the quality of these three alcoholic beverages can be ensured because the PEF technology can be applied in the absence of heat. In addition, the main negative effect of PEF technology is discussed as well.     

Occurrence of biogenic amines in beers from Chilean market

The presence of tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine was determined for the first time in beers commercialized in Chilean market. Dansylated amines were separated on a Zorbax-XDB C₁₈ column using a binary mobile phase composed of acetonitrile and 20 mmol L⁻¹ ammonium formate, pH 5.5. Chromatographic conditions were optimized using an experimental design, and validation was carried out following ICH recommendations. Calibration data fitted a linear regression model with R² > 0.996. Repeatability (n = 6) and intermediate precision (n = 3) in matrix showed RSD values lower than 5.00% and 5.21%, respectively. Recoveries at three different concentrations ranged from 75.50 to 96.48%. The proposed method was applied to determine the biogenic amines content in 101 beer samples produced by macro- (n = 65) and microbreweries (n = 36) using low (n = 63) and high fermentations (n = 38). Biogenic amines content in beer samples ranged from 0.53 to 85.04 mg L⁻¹, from which beers produced by microbreweries (19.13 ± 16.92 mg L⁻¹) showed a significant higher biogenic amines content (P = 0.0021) than beers produced by macrobreweries (9.65 ± 4.50 mg L⁻¹). Putrescine was the principal biogenic amine found in all kind of beers regardless origin, and the type of fermentation and brewery. Only 2 samples presented relevant levels of histamine and tyramine, but both below the limits reported by the European Food Safety Authority (EFSA). Thus, it can be concluded that beers commercialized in Chile are not a serious toxicological risk (e.g. hypertensive crisis) regarding the type and content of biogenic amines.     

再生沥青混合料水稳定性能的对比分析

以原样SHELL60—80沥青和对其进行两次不同老化程度后的再生沥青为结合料配制同种级配（AC-16C）的原样沥青混合料和再生沥青混合料，然后对其进行短期老化和长期老化，测试其在三个不同阶段（新鲜阶段、短期老化阶段、长期老化阶段）的水稳定性能，对比分析其的水稳性能，评价再生沥青混合料的抗水损坏能力。     

A novel dispersive liquid-liquid microextraction (DLLME) gas chromatography-mass spectrometry (GC-MS) method for the determination of eighteen biogenic amines in beer

A novel dispersive liquid-liquid microextraction (DLLME) gas chromatography mass-spectrometry (GC-MS) method was developed for the determination of 18 biogenic amines in beers. The method features the simultaneous extraction/derivatization of the amines providing a simple and fast mode of extract enrichment. A mixture of acetonitrile (dispersive solvent; 1.0 mL), toluene (extractive solvent; 325 μL), and isobutyl choloroformate (derivatizing reagent; 25 μL) was used as extractive/derivatizing reagent, added to 5 mL of sample. The proposed method showed good linearity (correlation coefficients > 0.997), good recoveries (from 72 to 113%), and good intra-day precision (below 13%) and inter-day precision (below 14%). Moreover, detection limits were never over 2.9 μg L⁻¹. The developed method was successfully applied to the analysis of 22 beer samples commercialized in Portugal. Fourteen of the eighteen biogenic amines analyzed were found in most of the beers, with predominance of putrescine, tyramine, dimethylamine, cadaverine, pyrrolidine and 1,3-diaminopropane.