The Impact of High Frequency Ultrasound Waves on Diluted Whey Proteins Resulted From Dairy Processing (original) (raw)
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Research Journal of Pharmaceutical, Biological and Chemical Sciences, 2014
In this study, the effect of high frequency ultrasound (2.4MHz) on different low concentrations of yogurt and cheese whey proteins has investigated. Whey protein obtained directly from Jordan university yogurt factory, was diluted with distilled water to get different solutions with wide range of concentration, namely 0.1-50ppm. These prepared solutions have exposed to ultrasound irradiation for 20, 40, and 60 minutes. Ultrasound was found to increase the concentration of protein with the increase of time. This enhancement in concentration was defined as enrichment value (R). The enrichment value has reached a value more than 2 for whey protein produced from yogurt, and more than 2.5 of its initial concentration for whey protein produced from cheese. The results suggest that ultrasound waves have caused an increase in protein solubility, due to a change in protein conformation that allowed the hydrophilic part to expose more to water side. The kinetic study for data was revealed that the solubility of whey protein is almost first order in the case of yogurt whey, while it is not first order for whey resulted from cheese whey. Keywords: ultrasound, water treatment, whey protein enrichment, environmental management, industrial wastewater, protein recovery, dairy manufacturing, dairy waste.
Ultrasonics Sonochemistry, 2018
Casein and whey proteins respond differently to ultrasound treatment depending on the individual protein fraction and the delivered energy density. The main aim of this study was to determine the sonication-induced physiochemical and structural changes of protein solutions with varying casein to whey protein ratios as a function of processing time at 20 kHz ultrasound. Four different casein:whey protein ratios (80:20, 60:40, 50:50, 40:20) were prepared. Upon sonication, there was a reduction in particle size of the 80:20 and 60:40 ratios, but the particle size of 50:50 and 40:60 increased. Milk protein solutions with higher portion of caseins produced more hydrophobically driven aggregates while whey protein-rich milk protein solutions produced more disulphide mediated aggregates during sonication. Primarily, β-lactoglobulin was involved in the hydrophobic aggregation process and βlactoglobulin, bovine serum albumin and κ-casein participated in the disulphide aggregation process at all ratios.
Effect of ultrasound treatment on particle size and molecular weight of whey proteins
Journal of Food Engineering, 2014
The aim of this study was to observe the effect of ultrasound on particle size and molecular weight of whey proteins. In this work high-intensity ultrasound (20 kHz probe and 40 kHz bath) were used. 10 wt.% protein model suspensions of whey protein isolate (WPI) and whey protein concentrate (WPC-60) were treated with ultrasound probe (20 kHz for 15 and 30 min) and ultrasound bath (40 kHz for 15 and 30 min). The results of particle size distribution have shown that, after treatment with an ultrasonic probe of 20 kHz, ultrasound caused a decrease in particle size, narrowed their distribution, and significantly increased the specific free surface in all samples. After treatment with ultrasonic bath of 40 kHz, there was a significant reduction in the size of particles. After treatment with probe of 20 kHz there was a significant decrease in molecular weight and protein fractionation. Ultrasonic bath treatment with 40 kHz ultrasound also showed significant changes in the composition of the molecular weight of protein fractions. Prolonged treatment of WPI with ultrasonic bath of 40 kHz encourages the formation of aggregates of molecules.
Food and health, 2022
The current work was conducted to explore the influence of ultrasound times and amplitudes on the solubility and turbidity of whey protein concentrate (WPC). Ultrasound (US) application was employed using VC-750 ultrasonic power equipment with the frequency of 20 kHz at various times (10, 20, and 30 minutes at 50% amplitude) and amplitudes (60%, 80%, and 100% for 5 min). The outcomes exhibited that the US process have a significant impact on both solubility and turbidity (p<0.05). The highest protein recovery was obtained for the samples exposed to 30 min the US at 100% amplitude (65.56%). WPC samples treated at 100% amplitude showed higher solubility compared to the other samples at 60% and 80% amplitudes. While the solubility of WPC samples treated with 10 min showed the lowest solubility (9.13%), samples treated with 30 min showed the highest solubility (38.14%). There is a negative relationship between solubility and turbidity. All US-treated samples showed less turbidity and higher solubility where the control WPC samples showed the most turbid structure (0.88 NTU) with the lowest solubility (4.15%). Overall, US treatment with 30-minutes at 100 % amplitude showed the highest solubility (65.56%) and least turbidity (0.26 NTU) compared to the other sonication times and amplitudes.
Ultrasonics Sonochemistry, 2011
The sonication-induced changes in the structural and thermal properties of proteins in reconstituted whey protein concentrate (WPC) solutions were examined. Differential scanning calorimetry, UV-vis, fluorescence and circular dichroism spectroscopic techniques were used to determine the thermal properties of proteins, measure thiol groups and monitor changes to protein hydrophobicity and secondary structure, respectively. The enthalpy of denaturation decreased when WPC solutions were sonicated for up to 5 min. Prolonged sonication increased the enthalpy of denaturation due to protein aggregation. Sonication did not alter the thiol content but resulted in minor changes to the secondary structure and hydrophobicity of the protein. Overall, the sonication process had little effect on the structure of proteins in WPC solutions which is critical to preserving functional properties during the ultrasonic processing of whey protein based dairy products.
The aim of this study was to investigate the influence of high intensity ultrasound on quality of reconstituted sweet whey in order to substitute thermal treatments i.e. pasteurization. Also, it was intended to study the influence of ultrasound on fermentation process of pasteurized or thermo-sonicated whey with respect to culture activation and sensory properties of the fermented whey. In the first stage, whey was subjected to treatments with different power inputs (480 W, 600 W) over 6.5, 8 and 10 min at constant temperature (45 °C, 55 °C). Treated whey samples were analyzed for microbiological quality, particle size distribution, protein content, acidity, electrical conductivity, viscosity and sensory properties. All of the analyzed parameters were compared with the control sample (pasteurized) and fresh whey. Subsequently, influence of high intensity ultrasound on pasteurized or thermo-sonicated whey fermentation with yoghurt culture and with monoculture Lactobacillus acidophilus La-5 was investigated. Ultrasound treatments were applied for culture activation prior to or after the inoculation. Whey thermo-sonication by nominal power of 480 W for 10 min at 55 °C resulted in better microbiological quality and sensory properties in comparison to whey pasteurization. Ultrasound treatments with nominal input power of 84 W over 150 s resulted in the highest increase of the viable count during the activation process. Whey fermentation by ultrasonicated culture La-5 lasted 30 min shorter and resulted in higher viable cells count. Industrial relevance: Attached paper (" Influence of high intensity ultrasound on microbial reduction, physico-chemical characteristics and fermentation of sweet whey ") reports the influence of high intensity ultrasound on quality and fermentation process of sweet whey. Also, the influence of high intensity ultrasound on pasteurized or thermo-sonicated whey fermentation with yoghurt culture and with monoculture Lactobacillus acidophilus La-5 was investigated. Whey proteins are thermo-labile proteins and degradable at higher temperatures (above 60 °C), and at conventional processing (pasteurization), denaturation and precipitation of proteins occur. Ultrasound gives a great replacement for pasteurization where precipitation does not occur. Also, ultrasonic treatment of the whey results in homogenization and thus, stability is increased. When microbiological cultures for fermentation, prior to the inoculation in the samples, are treated by ultrasound their activity is higher (explained in the paper) and thus fermentation is faster. From an economical point of view, processing by ultrasound can reduce costs a lot, since fermentation time is shorter, and the same effect as pasteurization is achieved. Ultrasonic treatment is a future in the dairy industry.
Effect of ultrasound on the physical and functional properties of reconstituted whey protein powders
Journal of Dairy Research, 2011
Aqueous solutions of reconstituted whey protein-concentrate (WPC) & isolate (WPI) powders were sonicated at 20 kHz in a batch process for 1-60 min. Sonication at 20 kHz increased the clarity of WPC solutions largely due to the reduction in the size of the suspended insoluble aggregates. The gel strength of these solutions when heated at 80°C for 20 min also increased with sonication, while gelation time and gel syneresis were reduced. These improvements in gel strength were observed across a range of initial pH values, suggesting that the mechanism for gel promotion is different from the well known effects of pH. Examining the microstructure of the whey protein gels indicated a compact network of densely packed whey protein aggregates arising from ultrasound treatment. Comparable changes were not observed with whey protein isolate solutions, which may reflect the absence of larger aggregates in the initial solution or differences in composition.