Recent Advances in Enzyme-Free Electrochemical Hydrogen Peroxide Sensors Based on Carbon Hybrid Nanocomposites

The significance of H2O2 in biological systems and its wide application in various areas, such as municipal wastewater, aseptic packaging, etc., enable the development of simple, stable, and highly sensitive...

Effect of Sporulation Conditions Following Submerged Cultivation on the Resistance of Bacillus atrophaeus Spores against Inactivation by H2O2

The resistance formation of spores in general and of Bacillus atrophaeus in particular has long been the focus of science in the bio-defense, pharmaceutical and food industries. In the food industry, it is used as a biological indicator (BI) for the evaluation of the inactivation effects of hydrogen peroxide in processing and end packaging lines’ sterilization. Defined BI resistances are critical to avoid false positive and negative tests, which are salient problems due to the variable resistance of currently available commercial BIs. Although spores for use as BIs have been produced for years, little is known about the influence of sporulation conditions on the resistance as a potential source of random variability. This study therefore examines the dependence of spore resistance on the temperature, pH and partial oxygen saturation during submerged production in a bioreactor. For this purpose, spores were produced under different sporulation conditions and their resistance, defined by the D-value, was determined using a count reduction test in tempered 35% liquid hydrogen peroxide. The statistical analysis of the test results shows a quadratic dependence of the resistance on the pH, with the highest D-values at neutral pH. The sporulation temperature has a linear influence on the resistance. The higher the temperature, the higher the D-value. However, these factors interact with each other, which means that the temperature only influences the resistance when the pH is within a certain range. The oxygen partial pressure during sporulation has no significant influence. Based on the data obtained, a model could be developed enabling the resistance of BIs to be calculated, predicted and standardized depending on the sporulation conditions. BI manufacturers could thus produce BIs with defined resistances for the validation of sterilization effects in aseptic packaging/filling lines for the reliable manufacture of shelf-stable and safe food products.

Synthesis of Ag-Au/Reduced Graphene Oxide/TiO2 Nanocomposites: Application as a Non-enzymatic Amperometric H2O2 Sensor

Background: Owing to the strong oxidizing and reducing properties of hydrogen peroxide (H2O2), it has been widely used in many fields. In particular, H2O2 is widely used in the aseptic packaging of drinks and milk. The residue of H2O2 in food is harmful to human health. Therefore, the quantitative detection of H2O2 is of great practical significance. Methods: The Ag-Au/RGO/TiO2 nanocomposites were facilely synthesized by photo-reduction approach. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize the synthesized Ag-Au/RGO/TiO2 nanocomposites. Cyclic voltammetry was used to analyze the electrochemical behavior of H2O2 on the Ag-Au/RGO/TiO2/GCE. Amperometry was applied for quantitative determination of the concentration of H2O2. Results: A novel Ag-Au/RGO/TiO2/GCE was prepared. The Ag-Au/RGO/TiO2/GCE displayed high electrocatalytic activity towards H2O2 reduction. An electrochemical reduction peak of H2O2 was achieved on the Ag-Au/RGO/TiO2/GCE. The current responses were linear with the concentrations of H2O2 in the range of 0.01-30 mM with the detection limit of 3.0 μM (S/N = 3). Conclusion: An amperometric sensor has been prepared for H2O2 detection using Ag- Au/RGO/TiO2/GCE. The Ag-Au/RGO/TiO2/GCE shows good performance for the determination of H2O2. The proposed sensor exhibits good selectivity and stability.

Analysis of contemporary meat and meat products’ processing methods

For today, the issue of maximum preservation of meat and meat products at all stages of their production, storage, transportation and realization does not lose its relevance. Existing ways of food products’ preservation for prevention of their microbiological damage are divided into three groups: physical, chemical and biological. The article gives an analysis of modern methods of meat and meat products’ processing. Physical (chill, freezing, super freezing, ionizing irradiation, ultraviolet irradiation, pressure processing, laser irradiation) and chemical (with the use of organic acids, trisodium phosphate, extracts of plants with bacteriostatic properties etc.) methods of meat and meat products’ preservation are characterized. The data on the methods for extension of realization term due to the use of modern packaging materials (modified atmosphere, system of ‘active packaging’ and aseptic packaging) is given. The advantages and disadvantages of each of these methods are indicated.

The functional features of production of sour-milk product with gluten-free flour

The work substantiates the choice of leaven in order to produce a sour milk product with the most desirable organoleptic characteristics. As a result of the study, the fermentation for yoghurt of Chr. Hansen (Denmark) was selected. These studies determines the choice of scientifically proven methods of fermentation of the following samples. Organoleptic analysis of four samples of dairy products with gluten-free flour was carried out. It was shown that the consistency in each sample was homogeneous and estimated by the tasting commission at 5 points. It was established that the color and smell of samples of the dairy product directly depends on the type of introduced gluten free flour. It is shown that the color in the first and the third samples is estimated at 4 points. The second sample was slightly inferior and was estimated at 3.7 points. The highest score (4.8) was the fourth sample of buckwheat and rice-corn flour. The taste of pure sour milk was present in all abovementioned samples. It was found that the content of buckwheat flour in the first and the second samples gave the product an excessive taste of “porridge”. The taste of corn flour was distinguishedly felt in the third sample. It was shown that the first three samples yielded the optimum taste of the fourth to 0.6–1.9 points. It was found that the most balanced is the sour milk sample of the product with buckwheat and rice-corn flour. All organoleptic characteristics were distributed evenly in it. A new technological approach was developed in preparation of the milk-flour mixture to the fermentation. The model of technological process of manufacturing of sour milk product with gluten-free flour is made, which allows to develop technological stages of product production with functional additives. The influence of technological parameters and prescript components on the organoleptic parameters of the dairy product has been established. It was shown that the fermentation of the selected sample proceeds for 8 hours at a temperature of 43 ± 2 °С. The product is cooled to a temperature of 18 °C before aseptic packaging. It is recommended to store the ready gluten-free dairy product for 14 days at a temperature of 4–6 °C. Studies conducted show that the developed formula of sour-milk product can be recommended for the production of dairy enterprises.