A suitable model of microbial survival curves for beer pasteurization

Innovative Rough Beer Conditioning Process Free from Diatomaceous Earth and Polyvinylpolypyrrolidone

In large-sized breweries, rough beer clarification is still carried out using Kieselguhr filters notwithstanding their environmental and safety implications. The main aim of this work was to test an innovative rough beer clarification and stabilization process involving enzymatic treating with Brewers Clarex^®, centrifuging, rough filtering across 1.4-μm ceramic hollow-fiber membrane at 30 °C, and fine filtering through 0.45-μm cartridge filter. When feeding an enzymatically-pretreated and centrifuged rough beer with permanent haze (H_P) of 2 or 14 European Brewery Convention unit (EBC-U), its primary clarification under periodic CO₂ backflushing yielded a permeate with turbidity of 1.0–1.5 EBC-U at a high permeation flux (2.173 ± 51 or 593 ± 100 L m⁻² h⁻¹), much greater than that typical of powder filters. The final beer was brilliant (H_P = 0.57 ± 0.08 EBC-U) with almost the same colloidal stability of the industrial control and an overall log reduction value (~5.0 for the selected beer spoilage bacterium or 7.6 for the brewing yeast) in line with the microbial effectiveness of current sterilizing membranes. It was perceived as significantly different in flavor and body from the industrial control at a probability level of 10% by a triangle sensory test, as more likely related to the several lab-scale beer-racking steps used than to the novel process itself.

A Preliminary Evaluation to Establish Bath Pasteurization Guidelines for Hard Cider

Though in-package water bath heat pasteurization for hard cider production is commonly employed to improve product safety and stability, there is a considerable lack of research-based guidelines to inform industry practices. In this study, fermented cider was bottled and inoculated with high populations of Saccharomyces cerevisiae and Zygosaccharomyces rouxii yeast. The bottles were then subjected to water bath pasteurization 60 °C at varying lengths of time. For both yeast species, populations were reduced to undetectable levels after just 1 min of processing time. Though validation of each individual process is recommended, cider producers may be able to sufficiently reduce the risks of spoilage organisms with minimal water bath pasteurization, especially when combined with other methods to reduce the presence of spoilage organisms.

Ethanol and Methanol Concentration in Commonly Used Brands of Ma-al-shaeer in Iran: Estimation of Dietary Intakes and Risk Assessment

Objectives

Ma-al-shaeer is a popular beverage in Islamic countries. The aim of this study was to determine the concentrations of methanol and ethanol in most consumed brands of Ma-al-shaeer in Iran.

Methods

Eighty-one Ma-al-shaeer samples which commonly used in Iran were provided. Methanol and ethanol contents were determined by gas chromatography with flame ionization detector.

Results

The mean methanol concentrations in Iranian and foreign brands was 129.84±205.38 mg/L and 110.157±135.98 mg/L, respectively. Although mean ethanol contents of Iranian brands was 1.2±2.41 mg/L, ethanol level in foreign ones was lower than LOQ.

Conclusion

Since the most Ma-al-shaeer brands had methanol pollution at different levels establishment of a definitive relationship between the methanol content and toxicological effects seem to be vital. EDI of methanol for Iranian people through consumption of Ma-al-shaeer was determined 0.023mg/kg bw/day.

Influence of ultrasound assisted thermal processing on the physicochemical and sensorial properties of beer

The aim of this study was to investigate the effect of ultrasound assisted thermal processing also known as thermosonication (TS) on selected physicochemical and sensorial properties of beer. A typical Chinese lager beer was treated by TS (24kHz frequency and 2.7W/mL volumetric power) for 2min at 40, 50, and 60°C, respectively. The main quality attributes of the beer, such as ethanol content, original extract, pH, and bitterness, were scarcely affected by three TS treatments. However, a significant increase in color value was observed after TS treatment at 60°C during storage. The protein sensitivity and colloidal haze of three TS-treated beers increased slightly. The results also revealed that the development of both yeast and spoilage bacteria (including lactic acid bacteria and aerobic bacteria) was inhibited for 12months of storage for the TS-treated samples except for the TS-treated beer at 40°C. Additionally, the TS-treated beer at 60°C resulted in a higher thermal load relative to other two TS samples (at 40 and 50°C) based on the results of oxidative stability. TS treatment at 60°C also had a minor negative effect on the volatile profile by increasing staling compounds compared with other two TS treatments. These results obtained therefore may serve as a reference of the potential application of the ultrasound assisted thermal treatment for the beer processing.

Modeling the pressure inactivation of Escherichia coli and Salmonella typhimurium in sapote mamey ( Pouteria sapota (Jacq.) H.E. Moore & Stearn) pulp

High hydrostatic pressure inactivation kinetics of Escherichia coli ATCC 25922 and Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028 ( S. typhimurium) in a low acid mamey pulp at four pressure levels (300, 350, 400, and 450 MPa), different exposure times (0-8 min), and temperature of 25 ± 2℃ were obtained. Survival curves showed deviations from linearity in the form of a tail (upward concavity). The primary models tested were the Weibull model, the modified Gompertz equation, and the biphasic model. The Weibull model gave the best goodness of fit ( R²_adj > 0.956, root mean square error < 0.290) in the modeling and the lowest Akaike information criterion value. Exponential-logistic and exponential decay models, and Bigelow-type and an empirical models for b'( P) and n( P) parameters, respectively, were tested as alternative secondary models. The process validation considered the two- and one-step nonlinear regressions for making predictions of the survival fraction; both regression types provided an adequate goodness of fit and the one-step nonlinear regression clearly reduced fitting errors. The best candidate model according to the Akaike theory information, with better accuracy and more reliable predictions was the Weibull model integrated by the exponential-logistic and exponential decay secondary models as a function of time and pressure (two-step procedure) or incorporated as one equation (one-step procedure). Both mathematical expressions were used to determine the t_d parameter, where the desired reductions ( 5D) (considering d = 5 ( t₅) as the criterion of 5 Log₁₀ reduction (5 D)) in both microorganisms are attainable at 400 MPa for 5.487 ± 0.488 or 5.950 ± 0.329 min, respectively, for the one- or two-step nonlinear procedure.

Application and possible benefits of high hydrostatic pressure or high-pressure homogenization on beer processing: A review

Beer is the most consumed beverage in the world, especially in countries such as USA, China and Brazil.It is an alcoholic beverage made from malted cereals, and the barley malt is the main ingredient, added with water, hops and yeast. High-pressure processing is a non-traditional method to preserve food and beverages. This technology has become more interesting compared to heat pasteurization, due to the minimal changes it brings to the original nutritional and sensory characteristics of the product, and it comprises two processes: high hydrostatic pressure, which is the most industrially used process, and high-pressure homogenization. The use of high pressure almost does not affect the molecules that are responsible for the aroma and taste, pigments and vitamins compared to the conventional thermal processes. Thus, the products processed by high-pressure processing have similar characteristics compared to fresh products, including beer. The aim of this paper was to review what has been investigated about beer processing using this technology regarding the effects on physicochemical, microbiology and sensory characteristics and related issues. It is organized by processing steps, since high pressure can be applied to malting, mashing, boiling, filtration and pasteurization. Therefore, the beer processed with high-pressure processing may have an extended shelf-life because this process can inactivate beer spoilage microorganisms and result in a superior sensory quality related to freshness and preservation of flavors as it does to juices that are already commercialized. However, beyond this application, high-pressure processing can modify protein structures, such as enzymes that are present in the malt, like α- and β-amylases. This process can activate enzymes to promote, for example, saccharification, or instead inactivate at the end of mashing, depending on the pressure the product is submitted, besides being capable of isomerizing hops to raise beer bitterness. As a consequence, the process may reduce steam demand and residue generation. Therefore, the use of high-pressure processing can potentially replace or be combined with heat processes usually applied to beer, thus bringing benefits to the sensory quality of the product and to the environment.