Dairy Whey Research Articles

Effects of combined high pressure and enzymatic treatments on the hydrolysis and immunoreactivity of dairy whey proteins

Effects of combined high pressure and enzymatic treatments on the hydrolysis and immunoreactivity of dairy whey proteins

Evaluation of the Residual Antigenicity of Dairy Whey Hydrolysates Obtained by Combination of Enzymatic Hydrolysis and High-Pressure Treatment

Dairy whey was hydrolyzed for 15 min with five food-grade enzymes (Alcalase, Neutrase, Corolase 7089, Corolase PNL, and Papain) at atmospheric pressure (0.1 MPa) and in combination with high pressure (HP) at 100, 200, and 300 MPa, applied prior to or during enzymatic digestion. The peptide profile of the hydrolysates obtained was analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), and their residual antigenicity was assessed by immuno-blotting with anti–β-lactoglobulin monoclonal antibodies and the sera from pediatric patients allergic to cow's milk proteins. Moreover, to evaluate the presence of residual trace amounts of casein in bovine whey hydrolysates, immunoblotting with anti–cow's milk protein polyclonal antibodies was performed. SDS-PAGE analysis showed that HP treatment increased hydrolysis by the proteases assayed, especially when it was applied during the enzymatic digestion. Positive reactions at the band corresponding to β-lactoglobulin were detected for Corolase PN-L and Corolase 7089 hydrolysates, except for those obtained under 300 MPa by the last protease. However, the immunochemical reaction was lower in the hydrolysis products obtained under HP than in those obtained at atmospheric pressure and after the HP treatment. On the contrary, no residual immunochemical reactivity associated with β-lactoglobulin was observed in the hydrolysates obtained by Alcalase and Neutrase under HP, and none was observed in any of the hydrolysis products obtained by Papain. The presence of traces of casein was not significant. These results suggest that HP combined with selected food-grade proteases is a treatment that can remove the antigenicity of whey protein hydrolysates for their use as ingredients of hypoallergenic infant formulae.

Conversion of agricultural feedstock and coproducts into poly(hydroxyalkanoates)

Aside from their importance to the survival and general welfare of mankind, agriculture and its related industries produce large quantities of feedstocks and coproducts that can be used as inexpensive substrates for fermentative processes. Successful adoption of these materials into commercial processes could further the realization of a biorefinery industry based on agriculturally derived feedstocks. One potential concept is the production of poly(hydroxyalkanoate) (PHA) polymers, a family of microbial biopolyesters with a myriad of possible monomeric compositions and performance properties. The economics for the fermentative production of PHA could benefit from the use of low-cost agricultural feedstocks and coproducts. This mini-review provides a brief survey of research performed in this area, with specific emphasis on studies describing the utilization of intact triacylglycerols (vegetable oils and animal fats), dairy whey, molasses, and meat-and-bone meal as substrates in the microbial synthesis of PHA polymers.

Simple Purification of Immunoglobulins from Whey Proteins Concentrate

We have developed a new protocol with only two steps for purification of immunoglobulins (Ig) from a protein concentrate of whey. Following this protocol, we have an 80% recovery of immunoglobulins, fairly pure. The purification was achieved by eliminating the BSA, via a strong adsorption on DEAE-agarose. Full desoprtion of the other serum proteins could be achieved without contamination with BSA. Thus, a protein solution containing only Ig and very small proteins (e.g., beta-lactoglobulins and alpha-lactalbumin) was obtained. Offering this protein mixture to a lowly activated aminated support, only Ig adsorbed on the support. It has been shown that BSA is able to interact with other proteins (including Ig and lactalbumins). This ability to form complexes with other proteins prevented the success of the direct adsorption of Ig on this mildly activated support, even although Ig should be the largest protein presented in dairy whey.

Beijerinckia indica L3 fermentation for the effective production of heteropolysaccharide-7 using the dairy byproduct whey as medium

A mutant strain of Beijerinckia indica L3 screened by a traditional chemical mutagenesis was grown in lactose-based mineral salts medium (MSM) for the production of heteropolysaccharide-7 (PS-7). The beta-galactosidase was expressed constitutively in the mutant and its activity was higher than that in parent strain. The highest amount of PS-7 produced by the mutant was 2.88 g/L with a viscosity of 4530 cP in lactose-based MSM medium. The PS-7 production was enhanced by the addition of 4 g/L glucose into lactose-based MSM medium, reaching 5.52 g/L with a viscosity of 39531 cP. PS-7 of 6.18 g/L with a viscosity of 45772 cP was produced from the mutant grown in whey medium. The PS-7 production from the mutant reached 7.04 g/L when 4 g/L glucose was added to the whey medium. Compositional analysis of PS-7 produced by the mutant grown in whey medium or lactose-based mineral salts medium showed that the ratios of glucose/rhamnose were maintained in the range similar to that of parent strain, indicating the same compositional structures of PS-7.

Mechanisms for the ultrasonic enhancement of dairy whey ultrafiltration

Low frequency ultrasound has been used to facilitate cross-flow ultrafiltration of dairy whey solutions. Experimental results show that ultrasonic irradiation at low power levels can significantly enhance the permeate flux with an enhancement factor of between 1.2 and 1.7. The use of turbulence promoters (spacers) in combination with ultrasound can lead to a doubling in the permeate flux. The application of a combined pore blockage/cake resistance model to the observed experimental data suggests that the use of ultrasound acts to lower the compressibility of both the initial protein deposit and the growing cake. Conversely, the pore blockage parameter is not significantly affected. The use of a gel polarization model shows that the ultrasonic irradiation increases the mass transfer coefficient within the concentration polarization layer. Electron microscopy results showed no evidence that the ultrasonic irradiation altered the membrane integrity. HPLC analysis of the whey proteins in the feed solution before and after sonication showed that the concentration profile of the whey proteins was also not affected by the sonication process.

The optimisation of ultrasonic cleaning procedures for dairy fouled ultrafiltration membranes

Ultrafiltration (UF) of whey is a major membrane based process in the dairy industry. However, commercialization of this application has been limited by membrane fouling, which has a detrimental influence on the permeation rate. There are a number of different chemical and physical cleaning methods currently used for cleaning a fouled membrane. It has been suggested that the cleaning frequency and the severity of such cleaning procedures control the membrane lifetime. The development of an optimal cleaning strategy should therefore have a direct implication on the process economics. Recently, the use of ultrasound has attracted considerable interest as an alternative approach to the conventional methods. In the present study, we have studied the ultrasonic cleaning of polysulfone ultrafiltration membranes fouled with dairy whey solutions. The effects of a number of cleaning process parameters have been examined in the presence of ultrasound and results compared with the conventional operation. Experiments were conducted using a small single sheet membrane unit that was immersed totally within an ultrasonic bath. Results show that ultrasonic cleaning improves the cleaning efficiency under all experimental conditions. The ultrasonic effect is more significant in the absence of surfactant, but is less influenced by temperature and transmembrane pressure. Our results suggest that the ultrasonic energy acts primarily by increasing the turbulence within the cleaning solution.

The immobilization of a thermophilic β-galactosidase on Sepabeads supports decreases product inhibition: Complete hydrolysis of lactose in dairy products

The β-galactosidase from Thermus sp. T2 (Htag-BgaA) is competitively inhibited by galactose (3.1 mM) and non-competitively inhibited by glucose (49.9 mM). These inhibitions were strongly reduced by immobilization on heterofunctional epoxy Sepabeads (boronate-epoxy-Sepabeads and chelate-epoxy-Sepabeads). The immobilized preparations displayed increased competitive inhibition constants ( K i) of galactose (boronate-epoxy-Sepabeads, 12.5 mM and chelate-epoxy-Sepabeads, 11.7 mM), whilst the enzyme K M (lactose) only doubled its value. A significant increment of the non-competitive constant was also found (by around a two-fold factor). These increments of the inhibition constants greatly impact on the industrial performance of the enzyme. Thus, while using soluble enzyme in the hydrolysis of 5% lactose, the reaction stopped at around 90% hydrolysis, both immobilized preparations to reached hydrolysis yields higher than 99%. These immobilized forms of β-galactosidase could be used in the total hydrolysis of lactose in milk or dairy whey even at 70 °C.

The effects of pressed sugar beet pulp silage (PBPS) and dairy whey on heavy pig production

The effects of pressed beet pulp silage (PBPS) replacing barley for 10% and 20% (DM basis) were studied on heavy pigs fed dairy whey-diluted diets.60 Hypor pigs (average initial weight of 28 kg), 30 barrows and 30 gilts, were homogeneously allocated to three experimental groups: T1 (control) in which pigs were fed a traditional sweet whey-diluted diet (the ratio between whey and dry matter was 4.5/1); T2 in which PBPS replaced barley for 10% (DM basis) during a first period (from the beginning to the 133rd day of trial) and thereafter for 20% (DM basis); T3 in which PBPS replaced barley for 20% (DM basis) throughout the experimental period. In diets T2 and T3 feed was dairy whey-diluted as in group T1.No significant (P>0.05) differences were observed concerning growth parameters (ADG and FCR). Pigs on diets containing PBPS showed significantly higher (<0.05) percentages of lean cuts and lower percentages of fat cuts. On the whole, ham weight losses during seasoning were moderate but significantly (P<0.05) more marked for PBPS-fed pigs as a probable consequence of their lower adiposity degree. Fatty acid composition of ham fat was unaffected by diets. With regard to m. Semimembranosus colour, pigs receiving PBPS showed lower (P<0.05) “L”, “a” and “Chroma” values.From an economical point of view it can be concluded that the use of PBPS (partially replacing barley) and dairy whey in heavy pig production could be of particular interest in areas where both these by products are readily available.

Characterization of drug release from diltiazem-loaded polylactide microspheres prepared using sodium caseinate and whey protein as emulsifying agents

The influence of milk protein emulsifying agents on the characteristics, particularly drug release, of polylactide microspheres was investigated. Diltiazem loaded polylactide (PL) microspheres were successfully prepared using the dairy proteins, sodium casinate (SC) and whey protein isolate (WPI) as the emulsifying agents. Microspheres were characerized in terms of microsphere yield, electron microscopy, particle size, drug loading, DSC and XRD analysis and drug release. The yields of microspheres obtained were 53-63% and were independent of the emulsifying agent used. SEM revealed that, regardless of the emulsifying agent employed, the microspheres were of good sphericity, but the surface appearance of the microspheres was not the same in all cases. The milk proteins resulted in microspheres approximately half the size of those obtained with methylcellulose (MC). Significant differences in drug loading were observed between the three emulgents, the MC systems giving the highest values. Release profiles were sigmoidal in shape and were well fitted to the equation ln (x/1-x) = k·t - k·tmax, reflecting degradation controlled drug release. The parameter k increased with drug loading, while tmax decreased. The relationships between the release parameters [P(k and tmax)] and loading (L) could be quantified by equations of the form P = a·LN, N being negative in the case of tmax. Apart from the effect on loading efficiency, neither SC nor WPI appeared to significantly alter drug release. The quantitative relationships observed in this study may have more general application in quantifying drug release from drug polymer composites at low loadings where polymer degradation controls drug release.

Separation of bovine immunoglobulin G and glycomacropeptide from dairy whey

The concentration of immunoglobulins (Ig) in whey by selectively removing major whey proteins such as α-lactalbumin (αLA), β-lactoglobulin (BLG) and bovine serum albumin (BSA) has been studied using a polystyrene anion exchanger IRA93 and Amicon YM100 membrane. A process with IRA93 and 100 kD membrane treatment has been used to prepare Igs-enriched products from HCl–casein and colostral whey. The content of IgG in the product was 43.3% for HCl–casein whey and 93% for colostral whey, respectively. IRA93 selectively adsorbs glycomacropeptide from cheddar cheese whey at pH 4.7. The effects of pH, NaCl and diafiltration on fractionation of whey proteins by ultrafiltration were also studied.

Comparison of particulate and continuous-bed columns for protein displacement chromatography

A conventional anion exchange column packed with porous particles (BioScale Q2), and a novel continuous-bed column (UNO™ Q1) were compared for displacement separation of dairy whey proteins with polyacrylic acid as displacer. The steric mass action model was investigated as a means to aid and accelerate this development. Characteristic charges and steric factors were measured for the proteins and the displacer according to the model, and used together with the affinity constant derived from the adsorption isotherms for simulations, as well as for the construction of the affinity and operating regime plots. If possible, the latter two were used to select conditions for the actual experiments. In the case of the particle-based column, experimental results and simulations did not agree. In addition, the operating regime plot could not be constructed. The affinity plot did predict the order in the displacement train correctly, but gave misleading information concerning the possible effect of a change in displacer concentration. This is taken to be a result of the porous nature of the particles, which handicaps, to some extent, the interaction of the proteins and the displacer molecules with the adsorptive surface. Results were considerably better in case of the continuous-bed column, where there is no intraparticulate surface.

Preparative ion-exchange chromatography of proteins from dairy whey

A preparative-scale ion-exchange chromatographic process is described for the separation of the four major proteins and lactose from sweet dairy whey. Experiments using a commercial anion-exchange resin were carried out to determine the optimum conditions for initially separating the proteins α-lactalbumin, β-lactoglobulin, bovine serum albumin, immunoglobulin G and lactose from a sweet dairy whey mixture. The separation was accomplished with simultaneous step elution changes in salt concentration and pH. It was found that the anion-exchange step was most effective in separating β-lactoglobulin from the feed mixture. Following the anion-exchange separation, its breakthrough curve was processed using a commercial cation-exchange resin to further recover the valuable immunoglobulin G. The whey output from an east Tennessee cheese manufacturer was used as a feedstream for the preparative scale experiments and as a reference in scaling to an economically optimized production level operation.

Industrial Production of Polyhydroxyalkanoates Using Escherichia Coll: An Economic Analysis

Disposal of plastic, in particular packaging, is a serious problem confronting many countries. Part of a solution lies in using biodegradable plastics such as polyhydroxyalkanoates (PHAs), which can be produced by bacterial fermentation. This paper presents an economic analysis of PHA production by fermentation using recombinant Escherichia coli , in order to identify areas where significant cost reductions are possible. Based on an annual production of 4300 tonnes of poly-hydroxybutyrate (PHB) from glucose supplemented with complex nitrogen sources, the break-even selling price per kilogram of plastic is US1995$6.08. A ten year plant life, 40% tax rate, 10% discount rate and a conservative process design based on existing technology are assumed. This cost is highly sensitive to PHB expression level and recovery strategy, and moderately sensitive to medium cost and cell growth yield on glucose. Maximum cell density achieved has little effect for the process design used in this analysis. At the same level of production, the cost can be easily reduced to between US1995$5.63kg −1 and US1995$3.59kg −1 by using dairy whey as a partial replacement for glucose as the carbon source. The price variation represents different constraints on whey availability and credits for whey disposal. Further price reduction will require significant changes to existing process technology. For example, a scenario incorporating 60% glucose substitution with concentrated dairy whey and a significantly altered processing strategy has the potential to reduce PHB production cost to US1995$2.67kg −1 . Significant work remains to develop and optimize such cost-effective designs.

Comparison of anion-exchange and hydroxypatite displacement chromatography for the isolation of whey proteins

In displacement chromatography, several substances may be isolated and concomitantly concentrated, which makes this separation procedure attractive for the processing of diluted product streams containing a number of high value substances. Here, the suitability of anion-exchange and hydroxyapatite displacement chromatography for the processing of technical dairy whey is investigated. The pH and flow-rate of the carrier, the displacer chemistry and, in case of the apatite, the particle diameter of the stationary phase are considered. As a consequence of the pH sensitivity of the β-loctoglobulin, one major whey component, apatite displacement chromatography is less then successful in whey separation. At a denaturing carrier pH (>8.5) the β-lactoglobulin zone is broad and stretches over the entire displacement train. At a lower carrier pH, previously successful polyanionic displacers do not bring about separation, while low-molecular-mass ones do, but they tend to overrun and thus contaminate the protein zones. In the case of anion exchange displacement chromatography, polyanions, especially polyacrylic acid (PAA, M r 6000), constitute suitable displacer. Here too, a carrier pH of 8.0 is most suited to the separation of the whey proteins. The low-molecular mass-displacer iminodiacetic acid (IDA, M r 133.4), on the other hand, displaces only α-lactalbumin. The β-lactoglobulin remains on the column. PAA is used as the displacer to process a dairy whey sample.

New Opportunities from the Isolation and Utilization of Whey Proteins

Management of dairy whey has often involved implementation of the most economical disposal methods, including discharge into waterways and onto fields or simple processing into low value commodity powders. These methods have been, and continue to be, restricted by environmental regulations and the cyclical variations in price associated with commodity products. In any modern regimen for whey management, the focus must therefore be on maximizing the value of available whey solids through greater and more varied utilization of the whey components. The whey protein constituents offer tremendous opportunities. Although whey represents a rich source of proteins with diverse food properties for nutritional, biological, and functional applications, commercial exploitation of these proteins has not been widespread because of a restricted applications base, a lack of viable industrial technologies for protein fractionation, and inconsistency in product quality. These shortcomings are being addressed through the development of novel and commercially relevant whey processing technologies, the preparation of new whey protein fractions, and the exploitation of the properties of these fractions in food and in nontraditional applications. Examples include the following developments: 1) whey proteins as physiologically functional food ingredients, 2) α-lactalbumin and β-lactoglobulin as nutritional and specialized physically functional food ingredients, and 3) minor protein components as specialized food ingredients and as important biotechnological reagents. Specific examples include the isolation and utilization of lactoferrin and the replacement of fetal bovine serum in tissue cell culture applications with a growth factor extract isolated from whey.

The Effects of pH, Flow Rate, and Carbon Supplementation on Manganese Retention in Mesocosm Wetlands

AbstractIn an effort to obtain design parameters, a wetland mesocosm experiment was conducted to determine the effects on Mn retention of flow rate, inlet pH, and C supplementation. Sustained Mn retention was not achieved under reducing conditions when spent mushroom substrate was used as a substrate irrespective of flow rate, inlet pH, and C supplementation regimes. However, a lowered flow rate resulted in many significant effects on outlet water chemistry, including lower outlet Mn concentrations, higher outlet pH, lower outlet acidity, higher outlet alkalinity, higher outlet sulfide, lower outlet sulfate, and lower outlet redox potential. Supplementation of the wetlands with dairy whey resulted in marginally lower outlet Mn concentrations and marginally higher outlet sulfide levels. Wetlands receiving a neutral pH had lower outlet acidity, higher outlet alkalinity, lower outlet sulfate, but equivalent outlet Mn concentrations to wetlands receiving an acidic pH. Sulfate reduction was stimulated by reducing flow rates and metal loads. Metal extractions indicated that most of the Mn was retained as exchangeable Mn (37%), carbonate‐bound Mn (30%), and oxide‐bound Mn (21%), with most (64%) of the Mn retained at the surface of the wetland. The dominant form of Mn found in the subsurface substrate samples was exchangeable Mn (44%), indicating that stable forms of Mn did not form under reducing conditions.

Production of propionic acid by mixed cultures ofPropionibacterium shermanii andLactobacillus casei in autoclave-sterilized whey

Pure cultures ofPropionibacterium freudenreichii ss.shermanii did not grow in autoclave-sterilized cheese whey (121°C, 15 psi, 20 min) at whey concentrations greater than 2% (w/v) spray-dried sweet dairy whey. Propionic acid was produced from autoclave-sterilized whey by growingP. shermanii in mixed culture withLactobacillus casei. In medium containing 5–12% autoclaved whey solids and 1% yeast extract, the mixed culture produced 1.3–3.0% propionic acid, 0.5–1.0% acetic acid, and 0.05–0.80% lactic acid. All the lactose was consumed. Using pH-controlled fermentors (pH=7.0), mixed cultures produced at least 30% more propionic acid than cultures in which pH was not controlled.

4544637 Culture media from clarified dairy whey lactose permeates: Kathleen M Keggins, Ann C Davis, Edward M Sybert, Thomas Mays, Robert A Milch assigned to IGI Biotechnology Inc

4544637 Culture media from clarified dairy whey lactose permeates: Kathleen M Keggins, Ann C Davis, Edward M Sybert, Thomas Mays, Robert A Milch assigned to IGI Biotechnology Inc

The Development of a Precooked, Frozen, Egg-Based Pizza

A precooked, frozen egg-based pizza was developed to evaluate 12 crust formulations consisting of 70 to 85% egg albumen; various texture-improving ingredients such as wheat flour, corn oil, milk solids, sodium caseinate, and sweet dairy whey, or heavy white sauce; and Italian seasonings. Acceptability was tested with objective measurements including moisture loss and shear values and subjective measurements such as sensory evaluation. Results of the objective tests showed that the inclusion of 13.3% wheat flour with or without 5% corn oil minimized moisture loss without the addition of moisture-holding additives such as xanthan gum or sodium carboxymethylcellulose (CMC). Shear values of flour-containing albumen formulations were greater than those of other egg-based formulations. Taste panelists preferred the albumen-flour crusts over other egg bases because they were texturally more like conventional, flour-based pizza crusts. Sensory evaluation with both semi-trained and consumer panelists rated the egg pizzas as good as or better than commercially available, frozen, flour-based cheese pizzas.