Recent Advances in the Use of Transglutaminase in Cheese Production

Various enzymes are used in the food industry to improve product quality. The enzyme transglutaminase is used to modify proteins in various foods through the formation of inter- and intramolecular ?-(?-glutamyl) lysine bonds. Previous studies have revealed that using transglutaminase in cheese production can increase the yield and enhance the characteristics of various types of cheese. However, the enzyme concentration, temperature, and pH influence the quality of cheese. This review aimed to discuss the potential of transglutaminase in cheese production. Our analysis showed that transglutaminase catalyzes the formation of covalent bonds between milk proteins (crosslinking), which results in a greater amount of casein trapped from whey and a higher yield of curd. Transglutaminase can also reduce production costs without negatively affecting cheese quality. These findings should prove useful in developing cheese products to improve consumer satisfaction.

The Different Hopping Methods Mathematical Models

Статья посвящена вопросу сравнения двух способов охмеления - классического и инновационного «холодного» способа внесения хмеля при дображивании пива, - а именно оценке основных факторов процесса, влияющих на интенсивность образования изоксантогумола, характеризующего тона горечи в пиве. Приведены результаты исследования качественных показателей модельных растворов, позволяющих минимизировать влияние прочих органических соединений на уровень содержания изоксантогумола в среде. Математическая оценка зависимостей позволила получить многофункциональные уравнения зависимости содержания изоксантогумола от ряда параметров, играющих важное значение при различных способах охмеления в технологии пивоварения. Математический анализ позволил выявить высокую достоверность полученных данных. Анализ полученных качественных характеристик в доверительном интервале р ≥ 0,95 позволил при классическом способе охмеления выявить влияние рН среды, а при «холодном» способе - живых дрожжевых клеток, преобразующих ксантогумол в изоформу. Основная часть полученных результатов согласовалась с ранее полученными относительно влияния рН, продолжительности охмеления, корреляции количества полифенолов, уровня изоксантогумола. Однако, влияние жизнедеятельности дрожжевых клеток не было отмечено ни в одном труде, что требует дополнительного экспериментального исследования. The article is devoted to the issue of comparing two hopping methods - the classical and innovative «dry hopping» method during the beer maturation, namely, the process main factors assessment that affect the isoxanthohumol formation intensity, which characterizes the beer bitterness tone. The model solutions qualitative indicators study results, which allow minimizing the effect of other organic compounds on the level of isoxanthohumol content in the medium, are presented. The dependences mathematical assessment made it possible to obtain multifunctional equations for the dependence of the isoxanthohumol content on several parameters that play an important role in various methods of hopping in brewing technology. Mathematical analysis made it possible to reveal the high reliability of the data obtained. The obtained qualitative characteristics analysis in the confidence interval p ≥ 0.95 made it possible to reveal the medium pH influence with the classical method of hopping, and with the «dry hopping» method - living yeast cells that convert xanthohumol into an isoform. Most of the results obtained were consistent with those previously obtained regarding the effect of pH, duration of hopping, and the correlation between the polyphenols amount and the isoxanthohumol level. However, the influence of the yeast cells vital activity was not noted in any work, which requires additional experimental research.

Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase

The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte’s pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.

Contrasted release of insoluble elements (Fe, Al, rare earth elements, Th, Pa) after dust deposition in seawater: a tank experiment approach

Lithogenic elements such as aluminum (Al), iron (Fe), rare earth elements (REEs), thorium (232Th and 230Th, given as Th) and protactinium (Pa) are often assumed to be insoluble. In this study, their dissolution from Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 d under controlled conditions including controls without dust addition as well as dust seeding under present and future climate conditions (+3 ∘C and −0.3 pH). Unfiltered surface seawater from three oligotrophic regions (Tyrrhenian Sea, Ionian Sea and Algerian Basin) were used. The maximum dissolution was low for all seeding experiments: less than 0.3 % for Fe, 1 % for 232Th and Al, about 2 %–5 % for REEs and less than 6 % for Pa. Different behaviors were observed: dissolved Al increased until the end of the experiments, Fe did not dissolve significantly, and Th and light REEs were scavenged back on particles after a fast initial release. The constant 230Th/232Th ratio during the scavenging phase suggests that there is little or no further dissolution after the initial Th release. Quite unexpectedly, comparison of present and future conditions indicates that changes in temperature and/or pH influence the release of Th and REEs in seawater, leading to lower Th release and a higher light REE release under increased greenhouse conditions.