Thermal denaturation of α-lactalbumin and β-lactoglobulin in cheese whey: effect of total solids concentration and pH

1979 ◽  
Vol 46 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Robyn M. Hillier ◽  
Richard L. J. Lyster ◽  
Gordon C. Cheeseman
Keyword(s):  
Genetic Variants ◽  
Thermal Denaturation ◽  
Cheese Whey ◽  
Polyacrylamide Gel Electrophoresis ◽  
Electrostatic Charge ◽  
Total Solids ◽  
Solids Concentration ◽  
Lactose Concentration ◽  
Solids Content ◽  
Β Lactoglobulin

SUMMARYMeasurements of residual native protein remaining after heat treatment of cheese whey have been made using quantitative polyacrylamide gel electrophoresis. The results have been expressed in terms of kinetic constants. The effect of concentration was investigated up to 3 times the normal total solids content, dialysis treatments were used to study the effect of non-protein constituents, and the effect of pH was studied at pH 4, 6 and 9. The results indicated that increased total solids (TS) concentration slowed the denaturation of β-lactoglobulin A and B (β-lg A, β-lg B) but hastened the denaturation of α-lactalbumin (α-la). However, increased lactose concentration slowed the denaturation of both α-la and β-lg, perhaps by preventing formation of heat-induced complexes. Increased Ca concentration, up to 0.4 mg/ml, tended to slow the denaturation of both proteins, but further increase in Ca up to 0.9 mg/;ml produced little effect. The rate of denaturation of both α-la and β-lg was slower at pH 4 than at pH 6 or 9, and was probably slowest at the isoelectric point. However, not all the changes associated with pH could be explained in terms of net molecular electrostatic charge. The genetic variants of ′β-lg showed different heat stabilities – below 90 °C β-lgA was more stable than β-lgB, but above 90 °C the situation was reversed at all TS concentrations, and pH 6. However, at pH 4 and 9, °-lgA was less stable than °-lgB over the entire temperature range at normal concentration.

scholarly journals Whey pretreatments before ultrafiltration

1994 ◽  
Vol 3 (5) ◽  
pp. 473-479
Author(s):  
Tuomo Tupasela ◽  
Heikki Koskinen ◽  
Pirkko Antila
Keyword(s):  
Protein Content ◽  
Dry Matter ◽  
Whey Proteins ◽  
Ph Adjustment ◽  
Total Solids ◽  
Heat Treated ◽  
Protein Membrane ◽  
Membrane Isolation ◽  
Solids Content ◽  
Β Lactoglobulin

Whey is a by-product of cheesemaking. Whey dry matter contains mainly lactose, but also valuable whey proteins. The aim of this study was to develop improvements to whey protein membrane isolation processes. In our trials CaCl2 -added, pH-adjusted and heat-treated wheys were found to have MF (microfiltration) permeate fluxes about 30% higher than in untreated MF whey. The total solids and protein content of the MF permeates decreased compared to the original wheys. UF (ultrafiltration) trials were conducted using MF whey to compare it with centrifugally separated whey. The MF whey consistently maintained an UF flux about 1.5 to 2.5 times higher than that of the separated whey. Differently treated MF whey UF permeate fluxes also showed a difference. With CaCl2 addition, pH adjustment and heat treatment, the UF permeate fluxes were about 20 to 40% higher than when only MF was used. The total solids content decreased in each trial. The protein content of the UF concentrate also decreased compared to the MF permeate. The (β-lg (β-lactoglobulin) and α-la (α-lactalbumin) content was almost the same in UF concentrates as in MF permeates.

Determination of Ethanol in Whey-Sugar Solutions by Freezing

1982 ◽  
Vol 45 (1) ◽  
pp. 26-28 ◽  
Author(s):  
B. J. DEMOTT
Keyword(s):  
Specific Gravity ◽  
Cheese Whey ◽  
Freezing Point ◽  
Cottage Cheese ◽  
Yeast Fermentation ◽  
Kluyveromyces Fragilis ◽  
Total Solids ◽  
Solids Concentration ◽  
Treated Sample

The composition of solutions undergoing yeast fermentation was simulated by using direct-acid-set cottage cheese whey containing increasing amounts of ethanol (0 to 5.4%) with decreasing amounts of sucrose (10 to 0%). Each decrease of 1 g of sucrose per 100 ml of whey accompanied by an increase of 0.54 g of ethanol decreased specific gravity 0.0046 unit and lowered the freezing point 0.159 H. Whey containing 10% added sucrose was treated as follows: (a) inoculated with Kluyveromyces fragilis, (b) carbohydrate splitting enzymes added and inoculated with K. fragilis and (c) carbohydrate splitting enzymes added and inoculated with Saccharomyces cerevisiae. All mixtures were incubated 48 h at 32 C during which six samples from each treatment were analyzed for total solids, specific gravity and freezing point. No difference (P>.05) was noted between samples treated with enzymes or those treated with the two yeasts cultures as related to decrease in total solids concentration or specific gravity. Each 0.001-H decrease in freezing point was accompanied by a total solids decrease of0.006 g per 100 g of whey in the non-enzyme treated sample, and 0.008 g and 0.010 g per 100 g whey in the enzyme-treated samples inoculated with K. fragilis and S. cerevisiae, respectively. Each 0.001-H change in freezing point was equivalent to a change of 0.00003 specific gravity unit in the non-enzyme treated sample and 0.000043 and 0.000048 specific gravity unit in the enzyme-treated samples inoculated with K. fragilis and S. cerevisiae, respectively. The precision with which freezing point can be determined suggests its use in evaluating the amount of ethanol produced during fermentation.

Utilization of Solar Energy for Sludge Drying Beds

1984 ◽  
Vol 106 (3) ◽  
pp. 351-357 ◽  
Author(s):  
A. S. El-Ariny ◽  
H. I. Miller
Keyword(s):  
Weather Conditions ◽  
Average Period ◽  
Drying Process ◽  
Total Solids ◽  
Solids Concentration ◽  
Process System ◽  
One Year ◽  
Sludge Drying ◽  
Solids Content ◽  
Experimental Runs

The present work is aimed to assess experimentally solar heated sludge drying beds located in the New Orleans, Louisiana metropolitan area with an appropriately sized solar system designed to operate on a fiberglass-covered drying bed. Another open drying bed was left without solar heating for comparative purposes. Five experimental runs were conducted over a one-year period to account for all weather conditions utilizing aerobically digested waste activated sludge. Compared to conventional beds, the solar beds achieved an average reduction of 50 percent in the drying period required to obtain a total solids concentration of 30 percent and an average reduction of 60 percent in the drying period of sludge to reach a total solids concentration of 60 percent. Sludge of total solids content of more than 90 percent was produced in an average period of 20 days under the solar drying process. System energy effects and economic analysis were also discussed.

scholarly journals Real-Time Determination of Total Solids in UASB Reactors Using a Single Emitter Ultrasonic Sensor

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1437
Author(s):  
Priscilla N. P. Neves ◽  
Lariza S. Azevedo ◽  
Martijn Hoep ◽  
Thiago Bressani-Ribeiro ◽  
Matthijs Wiersma ◽  
...  
Keyword(s):  
Real Time ◽  
Low Cost ◽  
Anaerobic Sludge ◽  
Retention Capacity ◽  
Total Solids ◽  
Solids Concentration ◽  
Solids Content ◽  
Definition Of ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

The lack of proper sludge withdrawal routines has been one of the main causes of solids washout and consequent deterioration of effluent quality from up-flow anaerobic sludge blanket (UASB) reactors treating sewage in developing countries. The establishment of an adequate sludge withdrawal routine depends on the knowledge of the sludge mass inside the reactor, but for this, it is necessary to continuously monitor the solid’s profile along the height of the digestion compartment of such reactors. Knowing the sludge concentration at the highest point of this compartment, immediately before the passage of the liquid to the settling compartment, allows the definition of more robust strategies for sludge discharge, in order to not exceed the retention capacity (storage) of solids in the reactor. To couple with that, a low-cost ultrasound sensor was developed and tested with the aim of monitoring total solids concentration inside UASB reactors. Bench and demo-scale tests were performed to validate the developed technology. Results have shown that the sensor can provide real-time values of total solids inside the reactor with 0.1% accuracy up to 1% total solids content.

A pilot web former designed to study retention-formation relationships

2010 ◽  
Vol 25 (2) ◽  
pp. 185-194
Author(s):  
Anna Svedberg ◽  
Tom Lindström
Keyword(s):  
Pilot Scale ◽  
Operating Conditions ◽  
Montmorillonite Clay ◽  
Speed Ratio ◽  
Good Reproducibility ◽  
Total Solids ◽  
Retention Aids ◽  
Solids Content ◽  
Relationship Of ◽  
The Relationship

Abstract A pilot-scale fourdrinier former has been developed for the purpose of investigating the relationship between retention and paper formation (features, retention aids, dosage points, etc.). The main objective of this publication was to present the R-F (Retention and formation)-machine and demonstrate some of its fields of applications. For a fine paper stock (90% hardwood and 10% softwood) with addition of 25% filler (based on total solids content), the relationship between retention and formation was investigated for a microparticulate retention aid (cationic polyacrylamide together with anionic montmorillonite clay). The retention-formation relationship of the retention aid system was investigated after choosing standardized machine operating conditions (e.g. the jet-to-wire speed ratio). As expected, the formation was impaired when the retention was increased. Since good reproducibility was attained, the R-F (Retention and formation)-machine was found to be a useful tool for studying the relationship between retention and paper formation.

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