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•The use of lactic acid bacteria (LAB) for industrial applications.•Inactivation of LAB using emerging technologies for food applications.•LAB stimulation using emerging technologies ...to obtain beneficial properties.
Lactic acid bacteria (LAB) have a long history of applications in the food industry for fermentation and preservation. This feature is due to their metabolic products that can improve the nutritional and sensory characteristics of foods as well as their antimicrobial compounds that contribute to extend the shelf life of food products. Some emerging technologies including pulsed electric fields (PEF), power ultrasound (US), high-pressure processing (HPP), ultraviolet (UV), and microwave (MW) have attracted great attention for their implementation in the food industry as mild processing technologies. They have the advantage of efficiently inactivating the microorganisms, along with maintaining the fresh attributes of the food products. When applied at a sub-lethal level, these technologies present the potential to enhance several processes, such as improved microbial growth and fermentation conditions, as well as modified metabolic properties of LAB. This review covers the characteristics of LAB and their applications in the food industry. It discusses the impacts of emerging technologies on these microorganisms, with a special focus on microbial inactivation, growth stimulation, and improvement of the beneficial features of LAB by emerging technologies.
In recent decades, microalgae species have focused the attention of several research groups and food industry as they are a great source of nutritionally valuable compounds. The use of ...environmentally friendly technologies has led to researchers and food industry to develop new alternative processes that can extract nutritionally valuable compounds from different sources, including microalgae. This note describes the potential use of some non-conventional methods including sub- and supercritical fluid extraction, pulsed electric fields, high-voltage electric discharges, high-pressure homogenization, ultrasound- and microwave-assisted extraction, which involve cell disruption to recover nutritionally valuable compounds from microalgae and can help to comply with criteria of green chemistry concepts and sustainability.
The application of strong electric fields in gases, water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical ...applications in biology, chemistry, and electrochemistry. More recently, electrical discharges have been investigated and are being developed in water for enhancing the extraction of biocompounds from different raw materials. This paper reviews the current status of research on the application of high voltage electrical discharges for promoting cell disruption in aqueous suspension of biological materials, with particular emphasis on application to biocompounds extraction.
Several studies have demonstrated the feasibility of pulsed electric fields (PEF) for different applications in food industry. PEF technology is therefore a valuable tool that can improve ...functionality, extractability, and recovery of nutritionally valuable compounds as well as the bioavailability of micronutrients and components in a diverse variety of foods. Additionally, other studies have shown the potential of PEF treatments to reduce food processing contaminants and pesticides. This opens the doors to new PEF applications in the food industry. This review focused on some of the most renowned traditional and emerging PEF applications for improvement of osmotic dehydration, extraction by solvent diffusion, or by pressing, as well as drying and freezing processes. The impact of PEF on different products of biological origin including plant tissues, suspension of cells, by-products and wastes will be analyzed in detail. In addition, recent examples of PEF-assisted biorefinery application will be presented, and finally, the main aspects of PEF-assisted cold pasteurization of liquid foods will also be described.
•PEF potential to develop energy efficient and environmentally friendly processes•PEF is a useful tool to improve extractability, and bioavailability of bioactives.•PEF ability to decrease drying temperature•PEF potential to reduce freezing time•PEF ability to reduce formation of processing contaminants and pesticides
Electroporation is a method of treatment of plant tissue that due to its nonthermal nature enables preservation of the natural quality, colour and vitamin composition of food products. The range of ...processes where electroporation was shown to preserve quality, increase extract yield or optimize energy input into the process is overwhelming, though not exhausted; e.g. extraction of valuable compounds and juices, dehydration, cryopreservation, etc. Electroporation is—due to its antimicrobial action—a subject of research as one stage of the pasteurization or sterilization process, as well as a method of plant metabolism stimulation. This paper provides an overview of electroporation as applied to plant materials and electroporation applications in food processing, a quick summary of the basic technical aspects on the topic, and a brief discussion on perspectives for future research and development in the field. The paper is a review in the very broadest sense of the word, written with the purpose of orienting the interested newcomer to the field of electroporation applications in food technology towards the pertinent, highly relevant and more in-depth literature from the respective subdomains of electroporation research.
The study was aimed at improvement of recovery of intracellular valuable compounds from olive kernels (Olea europaea). High voltage electrical discharges (HVED), pulsed electric field (PEF), and ...ultrasound (US) were applied as pretreatments before extraction. The influence of HVED energy input (0–109 kJ/kg), pH (2.5–12), and ethanol (0–50 %) on the efficiency of the extraction was studied. The extracts obtained immediately after pretreatments were analyzed for total phenolic compounds, antioxidant activity, proteins, and pigments. HVED treatment was demonstrated to be more effective than ultrasound and pulsed electric field in terms of energy input and effective treatment time to extract phenolic compounds and proteins. Moreover, the application of HVED increased significantly the aqueous and hydro-ethanolic extractions of total phenolic content (TPC), and proteins of the recovered extracts when energy input was augmented. pH and ethanol percentage had also a significant influence in TPC, protein, and antioxidant recovery. The interesting observation is that pH 2.5 resulted in the optimum conditions to recover TPC and antioxidant capacity. However, the higher protein content was found when pH 12 was used. Multiple response optimization showed that TPC, content of proteins, and antioxidant capacity (Trolox equivalent antioxidant capacity (TEAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) values) of the sample were further maximized after HVED pretreatment at energy input 66 kJ/kg at pH 2.5 followed by extraction in 49 % ethanol. TPC, content of proteins, TEAC, and DPPH values under such conditions of extraction were 626.6 mg GAE/L, 0.225 mg/mL, 9.80 mM TE, and 7.61 mM TE, respectively.
•Purification of polyphenols of apple skins by adsorption/desorption on the XAD-16 was studied.•Heterogeneous character of adsorption was revealed.•Sonication facilitated absorption kinetics and ...increased adsorption capacity.•Optimum desorption efficiency for polyphenols was observed at 50% concentration of ethanol.
The ultrasound (US) assisted purification of polyphenols of apple skins by adsorption/desorption on the poly-aromatic Amberlite adsorbent XAD-16 was studied. The adsorption steps were done at different temperatures (T = 25–40 °C) with application of US at different intensities (P = 0–400 W). The desorption steps were tested in aqueous ethanol solution at different concentrations of ethanol (Cet = 0–96%). The isotherm of polyphenol adsorption was well described using the Freundlich model. The data on adsorption kinetics and static isotherm evidenced the presence of adsorption on heterogeneous surface with broad distribution of adsorption times that can depend on content of polyphenols in the solutions and applied power of sonication. The studies of desorption revealed the optimum desorption efficiency of polyphenols at 50% concentration of ethanol. The desorption ratio was positively affected by the sonication during the adsorption step. The highest adsorption/desorption efficiency (recovery) was observed for polyphenols as compared with proteins and soluble matter content and it reached of ≈30.6% (0 W) and 68.9% (50 W) in absence and presence of sonication, respectively. The effects of high US power on the damage of XAD-16 were discussed. The obtained data evidenced on good perspective of application of adsorption/desorption procedure assisted by sonication for purification of polyphenols from apple skin extracts.
•Extraction of polyphenols from grapefruit peels using green solvents.•Intensification of extraction using High Voltage Electrical discharges (HVED).•Deep eutectic solvents and aqueous glycerol ...enhanced the extraction of polyphenols.•The addition of glycerol has reduced the energy of the pre-treatment by 6 times.•Solubility of naringin was estimated through a modelling of its Hansen parameters.
Deep eutectic solvents (DES) and aqueous glycerol were proposed as green alternatives to conventional solvents for the extraction of polyphenols from grapefruit peels. In order to increase the extraction kinetics and yields of polyphenols, high voltage electrical discharges (HVED) were used as a pre-treatment technology (energy varied between 7.27 and 218 kJ/kg). Results showed that the HVED energy input can be reduced, when the subsequent solid-liquid extraction was performed in 20% (w/v) aqueous glycerol or in DES (lactic acid: glucose) instead of water. The addition of glycerol has reduced the energy of the pre-treatment by 6 times. The same diffusivity of polyphenols (4 × 10−11 m2/s) was obtained in water from HVED pre-treated peels at 218 kJ/kg and in aqueous glycerol from pre-treated peels at 36 kJ/kg. The solubility of naringin, the main flavonoid compound of grapefruit peels in the solvents, was investigated through a theoretical modelling of its Hansen solubility parameters.
•PEF-assisted extraction of bio-compounds from apple peels was tested.•The correlations between the electrical conductivity disintegration index, Zc, and cell disintegration, Zd, were determined.•The ...efficiency bio-compounds (soluble matter content, °Brix, and total polyphenol content, TPC) from apple peels was analyzed.•The correlations between extraction of bio-compounds and Zc were discussed.
The pulsed electric field (PEF) assisted extraction of bio-compounds (soluble solids concentration, °Brix, and total polyphenol content, TPC) from apple peels was studied. The aqueous suspensions of apple peels were treated by PEF with different intensities, E (480–1200V/cm), and different treatment times, tPEF (0–2s). The cell disintegration was analyzed using measurement of electrical conductivity (disintegration index, Zc) and microstructure evaluation by confocal laser scanning microscopy (microscopic cell disintegration index, Zd). The near linear Zc (Zd) dependencies were obtained for PEF treatment protocols with different treatment time, tPEF, and electric field intensity, E. The °Brix and TPC extraction efficiencies were dependent upon applied value of E. For example, at the highest PEF intensity, E=1200V/cm, and Zc≈1, the enhancements in values of °Brix and TPC were approximately the same ≈3.15. However, at lower PEF intensities (480, 600 and 800V/cm) and the fixed value of Zc the extraction of soluble matter was more effective compared to TPC. Therefore, the extraction efficiency of different bio-molecules is not only affected by the level of tissue disintegration (by value of Zc). The other details of PEF protocols (e.g., value of E) may be also important.
In recent decades, glucosinolates and isothiocyanates have attracted the interest of scientific community due to healthy properties of these bioactive compounds and their role as natural ...antimicrobials and anticarcinogenic agents. However, these compounds can lose their properties and transform into antinutrients depending on processing conditions. At this stage of investigation, there is a need in evaluation of the commonly accepted and new emerging methods in order to establish the optimum conditions for preserving healthy glucosinolates and isothiocyanates. This paper reviews the conventional and new promising technologies that can be useful for extraction of appropriate glucosinolates and isothiocyanates from natural sources (i.e., Brassica vegetables). The impact of different preservation processes on degradation of glucosinolates and isothiocyanates is also discussed.
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