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... laboratory experimental apparatus used in this work is shown schematically in Figure 1. The main component of the system is a 0.2 liters AISI 329 stainless steel autoclave (NOWA- WERKE, Zurich, Switzerland) designed to operate up to 70 MPa and 350 °C; constant operating temperature is attained by a circulating a constant (± 0.1 °C) temperature water stream coming from an automatically controlled thermostat. ...
Citations
... Supercritical and subcritical gas sterilization methods have been the subject of active investigation since early 2000s [6,7] in the context of food industry requirements. The following significant advantages of this approach make it a promising candidate for a new sterilization standard for medical use: a) the low temperatures (often below 50 • C) reduce the likelihood of critical damage to polymer biomaterials and sharp surgical tools; b) the possibility of performing sterilization of objects inside sterile packaging makes the method practicable; c) the relatively simple design and operation (in comparison with gamma-ray and plasma methods) of the sterilization devices makes the method potentially reproducible for widespread general use at hospitals and clinics; d) the use of cheap consumable gas CO 2 that is readily available at industrial scale and can be captured and re-used after treatment reduce the barrier to widepread uptake. ...
The decontamination of medical tools is a sustainable alternative to the use of disposable items. Sub- and supercritical fluids can be applied to decontaminate the surfaces of most biomedical materials with relative instrumental simplicity and low capital and operational costs, and may offer a promising alternative to autoclavation. It is important to assess the extent of surface degradation, since CO2 has corrosion potential against metals and is soluble in polymers, and also forms a weak acid in the presence of residual humidity. Experimental results are reported for subcritical CO2 (37 oC, 50 bar, 2 h) decontamination of surgical stainless steel, Ti-6Al-4V alloy, PEEK polymer, ZrO2 ceramic and natural tooth enamel specimens seeded with E. coli, St. aureus, Pr. intermedia and C. albicans sealed inside polymer-paper packages after 1, 2, 5 and 10 cycles of treatment. Characterization by SEM and nanoindentation revealed that detectable alterations could be seen only for the first cycle of treatment, whilst subsequent 10 treatment cycles did not cause visible change. The findings provide a good basis for further research into the potential of the supercritical fluid decontamination approach.
... iii) Milk pasteurization -SCO 2 has been used to pasteurize skim milk. Di Giacomo et al. (2009) treated raw skim milk at 150 bar, 35-40°C and a CO 2 to milk feed ratio of 0.33. These authors reported a shelf-life of 35 days. ...
The use of supercritical fluids as solvents dates back about 142 years (1879), where the term gas extraction was first reported. Since then, the solvent power of several fluids within their supercritical state has been documented in hundreds of thousands of scientific publications. Within the supercritical state, CO2 exhibits liquid-like density and gas-like viscosity that result in higher solubility than liquid solvents. Industrially, SCO2 has been used for the decaffeination of coffee beans, production of antioxidants, extraction of species, and others. Contrary, SCO2 has not been an industrial reality yet in the dairy industry partially due to the lack of fundamental knowledge of phase equilibrium and mass transfer kinetics for specific dairy components and applications.
... Di Giacomo et al. (2009) studied the ability of sCO 2 to pasteurize and sterilize milk and reported that milk pasteurized using sCO 2 had its shelf life increased by 35 days without any sensory deterioration, while increasing the pressure affected the sensory score. Amaral et al. (2017) have extensively reviewed several works related to the use of sCO 2 in processing milk. ...
Milk, due to its perishable nature, requires some processing treatment to ensure its quality, safety, and enhanced shelf life. Conventionally, thermal treatment has been the preferred processing method. Moreover, the technology of manufacturing nearly all the major dairy products involves heating. However, the thermal treatment takes a toll on the nutritional as well as sensory quality of milk. Hence, the profound interest in novel non-thermal methods can be justified. In this chapter, the outlines of non-thermal techniques used in dairy processing like high-intensity ultrasound, high pressure processing, cold plasma, supercritical carbon dioxide, irradiation, and pulsed electric field are elucidated.
... significantly better taste than thermally pasteurized milk. Continuous SFE process with CO 2 solvent was developed for industrial production of non-thermal pasteurization of whole liquid milk [52,53]. Table 4 summarizes the studies on the use of microbial inactivation in milk using supercritical carbon dioxide. ...
In the present scenario of growing population and environmental concerns, consumers are having huge preferences
towards healthier, minimally processed and long shelf stable foods which in turn paved the way to develop new functional dairy
products. Numerous and wider range of possible methods with better nutritional emphasis and enhanced functionality of dairy
foods were emerging. Super Critical Fluid Extraction (SCFE) is one amongst the processes which is currently becoming popular
in modifying different food products to produce new ones. This SCFE gained prominence as an alternative to green technology
in the food processing industry. It is a fluid phase extraction processing method which operates in between a gas and liquid and
induces solubilization of solutes in a base food material. In this method, supercritical fluids most commonly CO₂ is used as a
solvent to separate one selective component from the base food material. SCFE can be varied for different foods upon altering
the two factors, i.e., pressure and temperature or both. The products obtained in milk and dairy processing with use of SCFE
had a higher shelf life and acceptable sensorial properties with minimal loss of quality attributes. In this review, some studies
related to the potential of SCFE and its microbial inactivation, milk fat analysis, milk fat fractionation and fat solubility, extraction
of cholesterol, vitamins, flavours, fat and applications of SCFE technology in dairy products and by-products more specifically
in butter, cheese, whey cream and buttermilk were discussed briefly.
Keywords: Functional dairy products; Supercritical fluid extraction;
Milk fractionation; SCFE applications
... significantly better taste than thermally pasteurized milk. Continuous SFE process with CO 2 solvent was developed for industrial production of non-thermal pasteurization of whole liquid milk [52,53]. Table 4 summarizes the studies on the use of microbial inactivation in milk using supercritical carbon dioxide. ...
Milk is an important nutritional food source characterized by a perishable nature and conventionally thermally treated to guarantee its safety. In recent years, an increasing focus on competing non-thermal food processing technologies has been driven mainly by consumers’ expectations for minimally processed products. Due to the heat sensitivity of milk, much research interest has been addressed to mild non-thermal pasteurization processing to keep safety, ‘fresh-like’ taste and to maintain the organoleptic qualities of raw milk. This review provides an overview of the current literature on non-thermal treatments as standalone alternative technologies to high-temperature short-time (HTST) pasteurization of drinking milk. Results of lab-scale experimentations suggest the feasibility of most emerging non-thermal processing technologies, including high hydrostatic pressure, pulsed electric field, cold plasma, cavitation and light-based technologies, as alternative to thermal treatment of drinking milk with premium in shelf life duration. Nevertheless, a series of regulatory, technological and economical hurdles hinder the industrial scaling-up for most of these substitutes. To date, only high hydrostatic pressure treatments are applied as alone alternative to HTSH pasteurization for processing of “cold pasteurized” drinking milk. Milk submitted to HTST treatment combined to ultraviolet light is currently accepted in EU countries as novel food.
Carbon dioxide (CO2) is an alternative hurdle technology that can kill microorganisms or prevent growth and spoilage to extend the shelf life of foods. This chapter presents the acceleration of the cheese-making process, the fractionation and purification of various milk and whey proteins, the extraction of specific fats and fatty acids, the synthesis of water-resistant edible packaging, and others. Carbon dioxide can affect microorganisms in two different ways, depending on the temperature and pressure employed. In general, increasing either the pressure, rate of agitation or exposure time employed during CO2 processing of food products enhances the resulting microbial deactivation. Although the benefits of CO2 to the dairy industry are clear and there are abundant data supporting its use to improve the microbial quality of raw milk, high-pressure CO2 treatment or the incorporation of CO2 to milk are not yet permitted.
