Whey Filtrate Research Articles

Growth and fatty acid profile of Nannochloropsis oceanica cultivated on nano-filtered whey permeate

Nano-filtered whey permeate (WP), a major by-product of dairy industry, is produced by membrane filtration of whey. The oleaginous microalga Nannochloropsis oceanica was successfully cultivated on WP without salinity and nutrient amendments. Growth, cell characteristics, and fatty acid profile of the cultures were analyzed using microscopy, flow cytometry, and GC analysis. WP was nitrogen limited, comprising primarily protein as a nitrogen source and only small amounts of free inorganic nitrogen (in the form of nitrate). Nannochloropsis oceanica (and associated bacteria) efficiently removed nitrate (100%), protein (87%), and phosphate (74%) from the whey permeate. Microscopic and flow cytometric analysis revealed diverse size distributions in whey permeate cultures, with significant cell aggregation attributed to low-salinity acclimatization and nitrogen limitation. Autofluorescence analysis revealed reduced photosynthetic activity in whey permeate-grown cells, possibly as a consequence of heightened mixotrophic activities on carbon source in the medium. Low nitrogen availability in whey permeate resulted in biomass with a fatty acid profile enriched in saturated fatty acids. Despite this, a considerable level of the omega-3 polyunsaturated fatty acid (in the form of eicosapentanoic acid or EPA) was detected at ca. 16% of total fatty acids. Whey permeate proved beneficial for the growth of N. oceanica and yielded high concentrations of eicosapentaenoic acid in the extracted lipids for potential applications in the feed/food industries.

Whey filtration: a review of products, application, and pretreatment with transglutaminase enzyme.

In the cheese industry, whey, which is rich in lactose and proteins, is underutilized, causing adverse environmental impacts. The fractionation of its components, typically carried out through filtration membranes, faces operational challenges such as membrane fouling, significant protein loss during the process, and extended operating times. These challenges require attention and specific methods for optimization and to increase efficiency. A promising strategy to enhance industry efficiency and sustainability is the use of enzymatic pre-treatment with the enzyme transglutaminase (TGase). This enzyme plays a crucial role in protein modification, catalyzing covalent cross-links between lysine and glutamine residues, increasing the molecular weight of proteins, facilitating their retention on membranes, and contributing to the improvement of the quality of the final products. The aim of this study is to review the application of the enzyme TGase as a pretreatment in whey protein filtration. The scope involves assessing the enzyme's impact on whey protein properties and its relationship with process performance. It also aims to identify both the optimization of operational parameters and the enhancement of product characteristics. This study demonstrates that the application of TGase leads to improved performance in protein concentration, lactose permeation, and permeate flux rate during the filtration process. It also has the capacity to enhance protein solubility, viscosity, thermal stability, and protein gelation in whey. In this context, it is relevant for enhancing the characteristics of whey, thereby contributing to the production of higher quality final products in the food industry. © 2023 Society of Chemical Industry.

Effect of production process and flavor additions on Greek yogur

Greek yogurt has become increasingly popular among consumers in recent years because of its high protein and low fat properties. There are two main processes for the production of Greek yogurt, i.e. whey filtration process and non-whey filtration process. The whey filtration process is to separate the whey from the regular yogurt; the non-whey filtration process is to add whey protein to the regular yogurt to increase the protein content of the yogurt. In China, due to the short time of developing Greek yogurt, the utilization efficiency of whey is not high, so the production is still mainly based on non-filtered whey process. At this stage, many companies have developed various flavors of Greek yogurt to meet the consumers' demand for different flavors and tastes of Greek yogurt. In this paper, by comparing the raw material ratios and processes of plain Greek yogurt with fruit flavored Greek yogurt, rose flavored Greek yogurt and chia seed Greek yogurt, the results obtained show that the added flavor additives have a small effect on the raw material ratios of Greek yogurt production, and the nature of the added flavor additives will have an effect on the time they are added in the production, resulting in a product with uniform texture and smooth taste.

Effect of operating parameters and modes in the filtration of acid whey using ultra- and microfiltration ceramic membranes.

Whey is a liquid by-product obtained by cheese elaboration, which is not completely used due to the large quantities produced. As a result, the whey is poured into rivers and soils and becomes a pollutant agent. The valorization of acid whey using membrane clarification was evaluated, where the effect of temperature and membrane cut-off were studied using acid whey. Permeability was three times higher at 70°C than 50°C (163.2±11.1 y 62.4±9.2 L/m2.h, respectively) for membranes with a cut-off of 0.2 µm. Furthermore, the permeate flux for this cut-off was three, six and ten times higher compared with the cut-off of 300, 150 y 50 kDa at 70°C, respectively. The clarification stage was scaled-up with 0.2 µm membranes, achieving about 22 L of whey filtered for Batch mode until a volume reduction factor (VRF) of 5 with protein retention of 68%. In Fed-Batch mode, the retention of protein was 61%, but the filtration could be carried out for longer, reducing fouling and filtering almost the double of the quantity of whey compared with Batch mode. In all cases, the turbidity of permeates was lower than 12 NTU (reduction >99%), regardless of whey turbidity whose values might be superior to 12,000 NTU.

Технологический прорыв аграрно-пищевых инноваций молочного дела на примере универсального сельхозсырья. Нанофильтрация

Aim. Consideration nanofiltration as a process of membrane technology – directed and controlled filtration of whey through special semipermeable partitions (membrane filters) with a pore size of 1-5 nm, carried out at a pressure of 0.7-4.0 MPa with the release of particles with a molecular weight of 0.5-1.0 kDa. Discussion. Nanofiltration allows you to separate the whey as a system by the size of the components – microparticles and macromolecules. In this case, from pre – separated, processed by microfiltration and ultrafiltration of whey to nanoconcentrate (retentate) pass almost all the compounds of whey, and in nanofiltrate (permeate) - only monovalent ions of mineral salts and partially some organic acids. Nanofiltration, in the logistics of molecular sieve separation of whey, takes over from ultrafiltration and is a harbinger of reverse osmosis. The theoretical foundations of the nanofiltration process are developed at a fairly good level. The basic element of the process is the membranes. Based on the conducted research, we can recommend the nanofiltration process for industrial processing of salted whey into milk sugar (lactose) and for concentrating whey and its ultrafiltrates before electrodialysis or ion exchange desalination. Nanofiltration is already widely used in the production of high-quality lactose (milk sugar). Considerable interest nanofiltration cottage cheese (acid) whey with the purpose of concentration, demineralization and sensory nanoconcrete for the enrichment of ice cream. Conclusion. Nanofiltration can be quite reasonably used for processing, within the framework of the Technological Breakthrough, universal agricultural raw materials – for example, whey and its ultrafiltrates – for the purpose of concentration, directed demineralization, lowering the level of organic acids and controlling sensorics. The resulting nanoconcentrate (retentate) can be used to scale functional products.

Технологический прорыв аграрно-пищевых инноваций молочного дела на примере универсального сельхозсырья. Ультрафильтрация

Aim. Consideration of ultrafiltration as a process of membrane technology – directed and con-trolled filtration of whey through special semipermeable filters (membrane filters) with a pore size of 10-100 nm, carried out at a pressure of 0.3-1.0 MPa. Material and Methods. The research was conducted using methods of graphical representation of information, trend analysis, comparison method, analogy and systematization, analysis and com-parison of empirical material. Discussion. Ultrafiltration allows you to separate whey as a system by the size of the components-microparticles and macromolecules. In this case, from pre-separated or Microfiltered whey to UV – concentrate (retentate), the remains of milk fat (up to 0.1%) and high-molecular compounds (at the level of 0.5%) – a complex of whey proteins, and UV-filtrate (permeate) – soluble compounds (lac-tose, mineral salts and BAS). Ultrafiltration, in the logistics of molecular sieve separation of whey, takes over from microfiltration and is a precursor to nanofiltration. The process of ultrafiltration of whey is well studied, developed, hardware designed and scaled in the dairy industry. The effective-ness of ultrafiltration purification of subsurface serum using various semipermeable membranes was studied. The criteria for selecting membranes were selectivity – maximum for protein and minimum for lactose, and the same permeability. The «neural network» methodology was used for system ap-proximation of research results. Conclusion. As a result of research, the technology of milk sugar (lactose) of the food category of quality and the original technological scheme for the production of dry whey have been devel-oped.in the dairy industry.

Investigation of Fouling Mechanisms Using Surface Morphology and Physicochemical Membrane Features

AbstractThe influences of membrane composition and surface morphology for membranes composed of polyethersulfone (PES) and fumarate alumoxane (Fum‐A) on fouling were investigated. Membrane fouling and blocking mechanisms were analyzed using the Hermia and combined pore blocking models. According to the Hermia fitted parameters, nanocomposite membranes revealed better antifouling properties. The lowest fouling coefficient belonged to the 2 wt % Fum‐A/PES membrane. In whey filtration, membrane surface morphology did not seem to have an important impact on the blocking mechanism as hydrophilicity. However, results clearly indicated a strong correlation between the surface morphology and the contribution of each individual fouling mechanism in the combined pore blocking/cake formation models.

OBTAINING OF Β-LACTOGLOBULIN BY GEL FILTRATION OF COW MILK WHEY

Milk whey proteins carry out a number of important biological functions and also they are precursors of many biologically active peptides (antihypertensive peptides, antagonists of opioid receptors, regulators of intestinal motility, immunomodulatory, anti-microbial and anti-cancer peptides, appetite regulators and so on.). An important stage in natural bioactive peptides obtaining from milk whey proteins is the isolation of homogeneous proteins-precursors. Considering the significant difference in the molecular masses of whey proteins, a promising method for their selection is gel filtration. The purpose of the research was the fractionation of bioactive peptides precursors from milk whey using gel filtration on Sephadex G-150. The whey was obtained from fresh skimmed milk after isoelectric precipitation of casein. Gel filtration was carried out on the columns from a liquid chromatography kit by the “Reanal” company. The fractional composition and the degree of homogeneity of milk whey proteins were determined by disc-electrophoresis in the plates of a polyacrylamide gel. A repeated gel filtration of fractions from the chromatographic peaks, separated into sections, was performed to increase the fractionation efficiency. While choosing a dextran gel for gel filtration of precursors of biologically active peptides from milk whey proteins, we have taken into account the range of their molecular weights (from 10000 to 150000 Da), the ability to form supramolecular structures (β-LG), as well as the previously obtained results of gel filtration. As a result, it was shown that repeated gel filtration of milk whey on Sephadex G-150 allows efficiently fractionate the proteins-precursors of bioactive peptides. The range of peptides and proteins molecular weights that can be fractionated on this Sephadex is from 5000 to 300 000 Da. The usage of repeated gel filtration on Sephadex G-150 with the chromatogram separation into sectors allows to effectively fractionate proteins-precursors of bioactive peptides from milk whey. In particular, homogeneous β-lactoglobulin (degree of homogeneity > 95 %) and partially purified α-lactalbumin, as well as a group of immunoglobulins and a proteose-peptone fraction were obtained.

The use of internal friction measurements for the study of ultra- and nanofiltration of modified curd whey

A technique is proposed for the experimental determination of internal friction in food materials, as well as a device based on a torsion pendulum with laser registration of the angle of rotation, which ensures the minimum relative displacement of the layers of the material under study in the measurement process. The definition of internal friction is based on finding the attenuation of a torsion pendulum connected to a cylinder immersed in the medium under study. As an example of the application of the method to food systems, the dependence of internal friction on viscosity in solutions of sucrose and glycerin is determined. This dependence is linear for sucrose solutions and non-linear for glycerol solutions, which may be due to the interaction of hydrated molecules in solutions. Examples of the application of internal friction measurements in the study of membrane concentration processes are given. The method of internal friction was used as an auxiliary rheological method in a comprehensive study of the process of deposition of concentrated substances on membranes during ultra- and nanofiltration of whey. Thus, it has been shown that, despite the thinness in comparison with the membrane, the polarization layer makes a significant contribution to the internal friction of the membrane-layer system. This leads to a sharp decrease in the flow of curd whey filtrate through the membrane, compared with the flow of water under the same conditions. The dependence of internal friction on the concentration in the curd whey that underwent electroflotation treatment was determined, as well as the thermal isomerization of the lactose contained in it. Using such curves, the relationships between the permeability coefficient Lp * in the Kedem–Kachelsky equation and the parameters of the nanofiltration process of given food systems can be found.

GEL FILTRATION OF COW MILK WHEY PROTEINS

The work considers the isolation of homogeneous precursor proteins of biologically active peptides from milk whey by gel filtration, in conditions that maximally ensure the preservation of their structure, composition, and properties. Considering the range of molecular masses of the main precursor proteins, the sephadex G-100 was selected for the gel filtration. As a result of the gel filtration of milk whey on a column with this sephadex, three peaks have been obtained, one of which was asymmetric and divided into two sectors. In total, four sectors from the three peaks have been received. Further, an electrophoretic analysis in the polyacrylamide gel of the proteins composition of all sectors was carried out. Sector A (the first peak) included immunoglobulins, lactoferrin, serum albumin. Sectors B and C (the second peak) consisted of β-lactoglobulin and α-lactalbumin in different ratios. The components of sector D (the third peak) had a small molecular weight and did not contain proteins. The next stage of the work was obtaining homogeneous lactoproteins. To this end, another gel filtration of the combined fractions of sectors A, B, and C was performed. Each of the chromatographic peaks obtained was divided into three ranges for the analysis of the proteins composition. Analytical electrophoresis of the combined chromatographic fractions of each range has shown that in six ranges out of nine, homogeneous precursor proteins of bioactive peptides were present. As a result of this repeated gel filtration on sephadex G-100, two homogeneous fractions (β-lactoglobulin, immunoglobulins) were obtained, which together, based on the results of the three gel filtrations, composed 59% of the whole milk whey protein. The processing of electrophoregrams, with the use of the image reading function imread, has shown high homogeneity of the fractions obtained (immunoglobulins ˃ 90%, and β-lactoglobulin ˃94%). These fractions were used to develop a biotechnology for obtaining and studying bioactive antihypertensive and bactericidal peptides from milk whey proteins.

The ultrafiltration efficiency and mechanism of transglutaminase enzymatic membrane reactor (EMR) for protein recovery from cheese whey

Transglutaminase was immobilised onto a polyethersulfone membrane surface and the resulting enzymatic membrane filtration efficiency and mechanism for the catalysis of protein cross-linking and separation from cheese whey was investigated. Transglutaminase was confirmed to be covalently immobilised onto the polyethersulfone membrane surface by Fourier transform infra-red and X-ray photoelectron spectroscopy. The protein recovery rate reached 85% in the transglutaminase enzymatic membrane reactor (EMR). The observed decrease of the protein recovery rate and relative membrane flux over time were mainly due to the decrease in enzymatic activity on the membrane surface after 1365 min of continuous operation. The total membrane resistance of the EMR was approximately 50% less than that of pure polyethersulfone membrane whey filtration. The main cause of the decreased resistance was that repulsive force energy was observed between cross-linking proteins and enzymatic membrane, which was identified through analysis based on the extended Derjaguine-Landaue-Verweye-Overbeek (XDLVO) theory.

Inline UV-Vis spectroscopy to monitor and optimize cleaning-in-place (CIP) of whey filtration plants

Cleaning in place (CIP) is a necessary, complex and costly process employed all throughout the food industry. CIP of membrane filtration plants is especially delicate as membranes have limited stability towards temperature and can be permanently damaged or gradually changed by cleaning chemicals used for every day. We investigated the capability of inline UV-Vis spectroscopy to elucidate the dynamics of CIP of membrane filtration plants as a gateway to control and optimize the process. For this investigation aged membranes that had been used for industrial ultrafiltration of whey were transferred to a pilot plant equipped with inline UV-Vis spectroscopy on both the retentate and permeate side. Then the dynamics of multiple fouling and cleaning of these membranes were investigated. The results indicate that the first CIP step, caustic cleaning could be shortened and possibly reduced in concentration. The second step of CIP, enzymatic cleaning, seems to be active even longer than the anticipated time. Challenges, first findings and future steps of full scale inline UV-Vis spectroscopy are discussed. We conclude that inline UV-Vis spectroscopy can be used to optimize the processing time, energy and chemicals needed for cleaning in place of membrane filtration plants.

Cheese whey management by catalytic steam reforming and aqueous phase reforming

Cheese whey is a yellowish liquid by-product of the cheese making process. Owing to its high BOD and COD values, this feedstock should not be directly discharged into the environment without appropriate treatment. The management of this wastewater has become an important issue, and new treatments must be sought. This work addresses the valorisation of cheese whey by steam reforming and aqueous phase reforming. The catalytic steam reforming of cheese whey turned out to be a promising valorisation route for H2 production from this effluent. This process enabled the organic compounds present in the cheese whey to be transformed into a rich H2 gas (35% of the C of the feed was transformed into a gas with 70vol.% of H2). This significantly reduced the amount of carbon present in the original feedstock, producing an almost carbon-free liquid stream. The aqueous phase reforming of cheese whey allowed 35% of the carbon present in the whey to be transformed into gases and 45% into valuable liquids. The gas was principally made up of H2 and CO2, while a mixture of added-value liquids such as aldehydes, carboxylic acids, alcohols and ketones constituted the liquid phase. However, both valorisation routes produced a substantial amount of solid. The formation of this solid was promoted by the presence of salts in the original feedstock and caused operational problems for both valorisation processes. In addition, it hampered gas production in the case of steam reforming and reduced gas and liquid formation when using aqueous phase reforming as the valorisation route. The filtration of cheese whey slightly decreased the solid formation in both processes due to the reduction of proteins and fats, both of which partly contribute to such formation. Less solid was formed in the experiments conducted with lactose than in those conducted with whole and with filtered cheese whey.

Fouling Mechanism Study of Nanoporous Membrane by Ultrafitration of Whey Proteins

One of the barriers during whey filtration using UF membrane is the fouling phenomenon of the membrane, which is caused by whey proteins. In this work, the UF membranes were prepared using polysufone (PSf), dimethyl formamide (DMF), 1 wt.% poly vinyl pyrrolidone (PVP) and different concentrations of LiCl via phase inversion induced by immersion precipitation. The prepared membranes were characterized using SEM, AFM, porosity and mean pore size measurements, ultrafiltration performance and fouling analysis. The roughness of the membrane surface increased after the addition of LiCl in the casting solution. The SEM images and the measured data of porosity and pore size showed that the porosity was significantly enhanced after modification with LiCl but the pore sizes of the membrane were reduced. The performance analysis of these membranes demonstrated that the modified membranes had higher pure water and whey flux in comparison to the neat membrane and all of the prepared membranes exhibited protein rejection higher than 90%. In order to evaluate the membrane fouling, the experimental fouling analyses were carried out and the Zedney's pore blockage and cake filtration model was employed. The membranes fouling in terms of pore-blocking slightly decreased after the addition of LiCl.

CLABSI Reduction using Novel Technology and Nursing Best Practice

Ultrafiltration (UF) is used for the concentration of whey proteins from whey. Membrane fouling during processing results in a decrease in flux, while the predominant molecular fouling reaction and fouling species are still largely unknown. Heat-induced whey protein aggregates are inevitably generated in industrial cheese-making processes, and were found to accelerate membrane fouling during whey concentration. By means of upstream microfiltration prior to UF, these aggregates can be selectively removed. By this means, UF flux could be increased up to twofold for the UF of sweet whey and threefold for acid whey. For filtration of sweet whey, significant calcium retention was observed. Therefore, membrane fouling for both whey types seem follow different molecular mechanisms. Besides the removal of whey protein aggregates, the retention of microorganisms and a log-reduction of up to log 3.5 was achieved by pre-filtration. Shelf-life of whey could be increased to two weeks without pasteurisation.

Temperature dependent membrane fouling during filtration of whey and whey proteins

Ultra- and microfiltrations are industrially applied for the concentration and fractionation of whey proteins. Thereby, either high (~50°C) or low (<10°C) processing temperatures can be selected to avoid microbial spoilage of the product. Filtration performance at the two temperature ranges was found to be significantly different. For this reason, this study focusses on the impact of temperature on membrane fouling during both ultra- and microfiltration of whey and whey protein suspensions. We found significantly different deposit layer structures at the two pore sizes investigated. During microfiltration (full whey protein permeation), membrane fouling due to adsorption processes was facilitated at temperatures ≤10°C and >35°C. For filtrations with fully retentive ultrafiltration membranes, an increase in processing temperature resulted in a decrease of specific fouling resistance, while deposit layer solid height increased. In cross-flow mode, fouling resistance was independent of temperature during acid whey microfiltration. A temperature increase during filtration of sweet whey resulted in a sharp increase of membrane fouling for temperatures above 40°C. When increasing temperature, the stronger fouling reaction in neutral pH-range could be attributed to both, the acceleration of thiol/disulfide reaction speed and calcium based protein cross-linking.

Interactive Effect of Agitation Speed and Aeration Rate on Heat Stable &amp;#946;- carotene Production From Mucor azygosporus Using Deprotenized Waste Whey Filtrate in Stirred Tank Reactor

Interactive effects of aeration rate and agitation speed on β-carotene production by Mucor azygosporus using waste whey filtrate in a laboratory fermenter were studied. The maximum β-carotene concentration (1045 µg/g dcw) was obtained at low agitation speed (150 rpm) and moderate aeration rate (1.0 vvm) after 72 h of incubation with a biomass of 7.9 g/L. The agitation and aeration provided better homogeneity in the culture medium with greater availability of nutrients and oxygen leading to a 2.8-fold increase in β-carotene production from that in the shake flask. Keywords: β-carotene, M. azygosporus, fermentation, whey filtrate, stirred tank reactor.

Enhancement of ultrafiltration-performance and improvement of hygienic quality during the production of whey concentrates

Ultrafiltration (UF) is used for the concentration of whey proteins from whey. Membrane fouling during processing results in a decrease in flux, while the predominant molecular fouling reaction and fouling species are still largely unknown. Heat-induced whey protein aggregates are inevitably generated in industrial cheese-making processes, and were found to accelerate membrane fouling during whey concentration. By means of upstream microfiltration prior to UF, these aggregates can be selectively removed. By this means, UF flux could be increased up to twofold for the UF of sweet whey and threefold for acid whey. For filtration of sweet whey, significant calcium retention was observed. Therefore, membrane fouling for both whey types seem follow different molecular mechanisms. Besides the removal of whey protein aggregates, the retention of microorganisms and a log-reduction of up to log 3.5 was achieved by pre-filtration. Shelf-life of whey could be increased to two weeks without pasteurisation.

Moving from recipe-driven to measurement-based cleaning procedures: Monitoring the Cleaning-In-Place process of whey filtration units by ultraviolet spectroscopy and chemometrics

We investigate the potential of ultraviolet spectroscopy (UV) to monitor cleaning of whey filtration membrane units. Based on sample collections in a full scale production environment two cases of cleaning monitoring by UV are evaluated. The first case demonstrates that UV can measure progress during both recirculation cleaning and the subsequent flushing of cleaning agents. The second case establishes that kinetics during the enzymatic cleaning step can be followed by UV and shows that different cleaning mechanisms are acting simultaneously. We also assess the detection limit for different whey components in a mixture design. Results show that UV in combination with partial least squares regression can quantify whey components down to between 10–20ppm for whey protein, 5–9ppm for whey fat, and 60–80ppm for non-protein/fat solids.

Comparison of antioxidant capacity, protein profile and carbohydrate content of whey protein fractions

Whey is used as an additive in food industry and a dietary supplement in nutrition. Here we report a comparative analysis of antioxidant potential of whey and its fractions. Fractions were obtained by size exclusion chromatography, before and after enzymatic digestion with pepsin or trypsin. Superoxide radical scavenging, lipid peroxidation inhibition and cupric ion reducing activities of different fractions were checked. Peptides were detected by SDS–PAGE and GC–MS was used to determine carbohydrate content of the fractions. All samples showed antioxidant activity and the second fraction of the trypsin hydrolysate showed the highest superoxide radical scavenging activity. CUPRAC value of this fraction was two-times higher than that of whey filtrate. The first fraction of the pepsin hydrolysate was the most effective inhibitor of lipid peroxidation. Each sample exhibited a different polypeptide profile. Different percentages of carbohydrates were identified in whey filtrate and in all second fractions, where galactose was the major component.