Visual observations and acoustic measurements of cavitation in an experimental model of a high-pressure homogenizer

Improving the quality of milk dispersion in a counter-jet homogenizer

Homogenization is a necessary process in the production of drinking milk and most dairy products. The specific energy consumption of the most common valve homogenizers reaches 8 kW h.t-1. A promising way to reduce it is the introduction of more effective counter-jet homogenizers. The purpose of these studies is to increase the efficiency of machines of this type through fuller use of their kinetic energy. To achieve this, the design of a ring reflector was developed and experimental studies were carried out to determine its influence on the efficiency of milk fat dispersion in a counter-jet homogenizer. Calculations were made to determine the reflector’s design parameters. An installation for experimental research has been developed, in which the required milk pressure is created with the help of compressed carbon dioxide. The dispersive indices of the milk emulsion were determined by computer analysis of milk sample micrographs obtained with an optical microscope and a digital camera using Microsoft Office Excel and Microsoft Visual Studio C# software using the OpenCV Sharp library. As a result of research, the formula for defining the angle of the reflector top has been determined analytically. Experimental studies proved its validity and allowed determination of the optimal diameter. A comparison of the dependence of the degree of homogenization on the excess pressure in a counter-jet homogenizer proves a 15 – 20% increase in the degree of dispersion when using a reflector. At the same time, specific energy consumption does not increase. Comparison of the distribution curves of milk fat globules by size after counter-jet homogenization and homogenization with a reflector suggests that the average diameter of fat globules for the experimental method decreases from 0.99 to 0.83 μm. This indicates the high quality of the dispersal characteristics of the milk emulsion after processing in a counter-jet homogenizer with a reflector.

Research on milk homogenization in the stream homogenizer with separate cream feeding

Homogenization, which is used in the technological schemes of production of most dairy products, is the most energy-intensive of the processes of mechanical processing of milk. One promising way to increase the energy efficiency of homogenization is to use separate homogenization and to use a little-researched stream homogenizer with separate cream feeding. The principle of its action is to pre-divide milk into cream and skim milk, and feed the fat phase with a thin stream into the stream of skim milk. This creates the conditions for achieving the high value of the Weber criterion - the main factor in the dispersion of milk fat. The purpose of these researches is to conduct experimental studies and determine the energy consumption and quality of homogenization of milk after treatment in a stream homogenizer. To achieve this goal, a designed experimental setup was used. The dispersive indices of the milk emulsion were determined by computer analysis of micrographs of milk samples obtained with an optical microscope and a digital camera using Microsoft Office Excel and Microsoft Visual Studio C # software using the OpenCV Sharp library. As a result of experimental studies, the critical value of the Weber criterion for homogenization of milk was determined, which is 28. The regularities of dispersion of milk fat in a stream homogenizer with separate feeding of the fat phase have been established. It is determined that the milk treatment in the experimental homogenizer allows us to achieve an emulsion with an average size of fat globules of about 0.8 μm (at the level of valve homogenizers). The value of the homogenization coefficient is obtained for the disruption of the fat globule in the conditions: subject to a single effect on the emulsion, without the influence of vibration and cavitation. This homogenization coefficient equals 3300 m3/2.s-1.

Food Structure Development in Emulsion Systems

A number of food products exist, in part or entirely, as emulsions, while others are present in an emulsified state at some point during their production/formation. Mayonnaise, butter, margarine, salad dressing, whipped cream, and ice cream represent some of the typical examples of emulsion-based foods. Controlled by both formulation and processing aspects, the emulsion architecture that is formed ultimately determines many of the attributes of the final food product. This chapter initially provides an overview of the basic constituents of emulsions and their influence on the microstructure and stability of conventional as well as more complex systems. The available spectrum of processing routes and characterization techniques currently utilized (or emerging) within the area of emulsions is then discussed. The chapter concludes with a concise outline of the relationship between food emulsion microstructure design and its performance (textural, rheological, sensorial, etc.).

Sonochemical and hydrodynamic cavitation reactors for laccase/hydrogen peroxide cotton bleaching

The main goal of this work is to develop a novel and environmental-friendly technology for cotton bleaching with reduced processing costs. This work exploits a combined laccase-hydrogen peroxide process assisted by ultrasound. For this purpose, specific reactors were studied, namely ultrasonic power generator type K8 (850 kHz) and ultrasonic bath equipment Ultrasonic cleaner USC600TH (45 kHz). The optimal operating conditions for bleaching were chosen considering the highest levels of hydroxyl radical production and the lowest energy input. The capacity to produce hydroxyl radicals by hydrodynamic cavitation was also assessed in two homogenizers, EmulsiFlex®-C3 and APV-2000. Laccase nanoemulsions were produced by high pressure homogenization using BSA (bovine serum albumin) as emulsifier. The bleaching efficiency of these formulations was tested and the results showed higher whiteness values when compared to free laccase. The combination of laccase-hydrogen peroxide process with ultrasound energy produced higher whiteness levels than those obtained by conventional methods. The amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and operating time (reduction of 90 min).

Tissue sample preparation in bioanalytical assays

Analytical quantitation of compounds in tissue has become a more prevalent addition to biological sample analysis in recent times. This increase will most certainly continue to bring the question of proper analytical method validation to the forefront of discussion. Thoughtful design of sample homogenization, analyte fortification and extraction can ensure a successful analysis. This review presents current trends in tissue sample preparation by harvesting, homogenization techniques, as well as concerns for calibrator and QC preparation. Strategies for consideration and resolution of common pitfalls in method development, for example stability issues and control biomatrices in endogenous analysis, are also presented.