A viscometric study of the breakdown of casein in milk by rennin and rennet

1961 ◽  
Vol 28 (2) ◽  
pp. 165-173 ◽  
Author(s):  
G. W. Scott Blair ◽  
J. C. Oosthuizen
Keyword(s):  
Intrinsic Viscosity ◽  
Order Term ◽  
Specific Viscosity ◽  
Reduced Viscosity ◽  
Reaction Constant ◽  
Zero Order Reaction ◽  
Straight Lines ◽  
Viscometric Study ◽  
Considerable Range ◽  
Ostwald Viscometer

SummaryIn the later stages of the reaction between rennin and casein drastic viscometric methods are undesirable, but in the first stages there is a fall in viscosity which may be satisfactorily measured in an Ostwald viscometer. Using fat-free milk, the viscosity at first falls linearly with time. At low rennet concentrations (Ce) this may be said to constitute a zero-order reaction (constant k0). At higher rennet concentrations and after longer times, the reaction passes to first order (constant k1). After very long times it doubtless becomes more complex.The values of k0 are proportional, over a considerable range, to the milk concentration (Cm), those of k1 being independent of Cm.For pure rennin k0 and k1 are proportional to Ce, but for commercial rennets they vary as a power (N) of Ce and the value of N appears to measure the rennin purity. The potentialities of the method for assessing rennet activities are also discussed.If the reduced viscosity (specific viscosity÷Cm) of fat-free milks is plotted against Cm, good straight lines are obtained which may be extrapolated to zero concentration to give a reliable value of intrinsic viscosity. The intrinsic viscosity falls progressively during the protein breakdown process but the slope of the curves (‘second order term’) remains unchanged.

The Terminology of Intrinsic Viscosity and Related Functions

1946 ◽  
Vol 19 (4) ◽  
pp. 1092-1098
Author(s):  
L. H. Cragg
Keyword(s):  
Intrinsic Viscosity ◽  
Kinematic Viscosity ◽  
Relative Viscosity ◽  
Flow Time ◽  
Inherent Viscosity ◽  
Routine Practice ◽  
Concentration Coefficient ◽  
Specific Viscosity ◽  
Reduced Viscosity ◽  
Relative Flow

Abstract The confusion existing in the use of symbols and names for Kraemer's “intrinsic viscosity” and other functions related to it is illustrated and deplored. The reasonable plea is made that one name be adopted for each function and that it be used with no other meaning. To stimulate discussion and ultimate action, the following names are proposed: “specific viscosity” for ηsp; “reduced viscosity” for ηsp/c, “inherent viscosity” for (ln ηr)/c; and “intrinsic viscosity” for [η], whether determined as “limiting reduced viscosity” limc→0 (ηsp/c), or as “limiting inherent viscosity” limc→0 (ηr/c), or as “limiting viscosity concentration coefficient” limc→0 (dηr/dc). Often, especially in routine practice, it is the relative kinematic viscosity νr, that is determined ; unless this is shown to be numerically equal to the relative viscosity ηr, the symbols and names of the derived functions should be modified accordingly: thus, (ln νr)/c inherent kinematic viscosity, [ν] intrinsic kinematic viscosity. Frequently, also, kinetic energy corrections are neglected; under these circumstances the suggested usage is tr, relative flow time, tsp/c reduced flow time, [t] intrinsic flow time, etc.

scholarly journals Viscometric Study of PC / PEG blends in THF solvent and Gamma-Rays Effect on the Viscosity of PC

2019 ◽  
Vol 24 (3) ◽  
pp. 105
Author(s):  
M.S. Buni ◽  
W.A. Solyman ◽  
S.A. Ali
Keyword(s):  
Intermolecular Interaction ◽  
Intrinsic Viscosity ◽  
Gamma Rays ◽  
Irradiation Time ◽  
Polymer Mixture ◽  
Dilute Solution ◽  
Reduced Viscosity ◽  
Huggins Constant ◽  
Viscometric Study ◽  
Dilute Solution Viscometry

In this research the intermolecular interaction between polycarbonate (PC) and polyethyleneglycol (PEG) in tetrahydrofuran (THF) solvent was studied, at 25˚C using a dilute solution viscometry method (DSV). The reduced viscosity  and intrinsic viscosity  and viscosity interaction parameter (b) were experimentally measured, we also discuss the compatility of a polymer mixture in terms of , and the effect of gamma-rays on the reduced viscosity and intrinsic viscosity and Huggins constant of (PC). The results show that the relation between  and C is liner within C=(0.9-2)g/dl, and viscometric constant KH decreases with irradiation time while  increases with Tirr.   http://dx.doi.org/10.25130/tjps.24.2019.055  

Some Approaches to Viscometric Study of Chitosan in Acetic Acid Solution

2016 ◽  
Vol 10 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Valentina Chernova ◽  
◽  
Angela Shurshina ◽  
Elena Kulish ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Intrinsic Viscosity ◽  
Acetic Acid Solution ◽  
Conformational State ◽  
Macromolecular Coil ◽  
Degree Of Swelling ◽  
Current Value ◽  
Viscometric Study

Some ways of estimating the values of the intrinsic viscosity of chitosan were analyzed. It was shown that the method of Irzhak and Baranov for estimating the current value of the intrinsic viscosity allows to adequately estimates the conformational state of the macromolecular coil and its degree of swelling.

Calculation of isokinetic temperature of non-catalyzed hydrolysis of substituted 3-(N-methylcarbamoyl)-1,3-diphenyltriazenes

1981 ◽  
Vol 46 (4) ◽  
pp. 898-905 ◽  
Author(s):  
Oldřich Pytela ◽  
Miroslav Večeřa ◽  
Pavel Vetešník
Keyword(s):  
Experimental Data ◽  
Isokinetic Temperature ◽  
Reaction Series ◽  
Significance Level ◽  
Common Intersection ◽  
Reaction Constant ◽  
Straight Lines ◽  
The Given ◽  
Kinetics Of ◽  
Hydrolysis Of

Temperature dependence of kinetics of non-catalyzed hydrolysis of substituted 3-(N-methylcarbamoyl)-1,3-diphenyltriazines has been measured. An optimized calculation method has been suggested for calculation of the isokinetic temperature and the experimental data have been evaluated. In all the cases it has been found that the hypothesis of common intersection of the straight lines log k vs1/T is rejected at the significance level α = 0.05, but, within approximate validity of the isokinetic hypothesis the isokinetic relation can be considered to be fulfilled in the given reaction series. The change of the reaction constant ρ connected with the change of the reaction mechanism shows a statistically significant correspondence with the change of the isokinetic temperature.

The Relationship of Oxygen Consumption to Age and Weight During the Post-Embryonic Growth of Locusta Migratoria L

1957 ◽  
Vol 34 (1) ◽  
pp. 29-41
Author(s):  
KENNETH U. CLARKE
Keyword(s):  
Oxygen Consumption ◽  
Locusta Migratoria ◽  
Live Weight ◽  
Normal Growth ◽  
Low Degree ◽  
Straight Lines ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship ◽  
Considerable Range

The weight and oxygen consumption of individual locusts, six from each instar, have been measured at 12-hourly intervals throughout each stadium. An analysis of short duration changes shows that fluctuations in live weight are unavoidable in the growing animal, and that they are accompanied by fluctuations in oxygen consumption. In time the latter lag behind the former. As the fluctuations of these two variables are out of phase, there is a considerable range of oxygen consumption which must be regarded as normal for any given weight. Calculations are made to find the limits of these fluctuations compatible with normal growth. The changes that occur during a stadium can be represented by a straight trend line for both weight and oxygen consumption. Exceptions occur in the case of weight of the adult where two straight lines are necessary, one for the growing phase and one for the steady phase of this instar. In certain cases in the fifth instar two straight lines are necessary to express the trend in oxygen consumption which may show an abrupt change in the middle of the stadium. A high degree of correlation is found between the trend lines for weight and oxygen consumption in the early instars. A low degree is found in latter instars where the weight increases and the oxygen consumption remains nearly constant. A curve representing the changes of weight and oxygen consumption that occur during the growth of the locust has been constructed.

Mechanochemical Transformation and Synthesis of Polymers

1961 ◽  
Vol 34 (1) ◽  
pp. 215-227 ◽  
Author(s):  
A. A. Berlin
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
High Speed ◽  
Rotation Speed ◽  
Mechanical Energy ◽  
Average Molecular Weight ◽  
Internal Stresses ◽  
Natural Polymers ◽  
Specific Viscosity ◽  
Mechanical Breakdown

Abstract The mechanical grinding, milling, mixing, homogenization, freezing and other processes of the physico-mechanical processing of high polymers are widely used in the industries of plastics, rubbers, synthetic fibers, food products, silicates and many other branches of technology. Some of these processes have a great significance in biochemistry, medicine and biology. An analysis of the available experimental data permits one to reach the conclusion that in the intensive grinding of natural polymers (cellulose, starch, proteins or synthetics (polystyrene, rubber, polyisobutylene, etc.) a mechanical scission (cracking) of the macromolecules is observed. The possibility of macromoleeular scission under the grinding of high molecular weight substances is due to the high probability of a localization of mechanical energy at different sections of the polymer chain, which under certain conditions causes internal stresses exceeding the strength of covalent or ionic bonds. Mechanical breakdown of macromolecules is possible not only with dry or wet grinding, but also by mechanical action on polymer solutions. Thus, for instance, Staudinger has shown that the high speeds and forces of friction developed in forcing a 0.005 molar tetralin solution of polystyrene, average molecular weight = Mave=6⋅106, through a platinum capillary bring about a scission of the macromolecules which is revealed in a decrease of about 30% in the specific viscosity of the solution. Forcing a solution of polyisobutylene (Mave=3.9×104–23×104) in dichlorobenzene through a capillary with a diameter of 0.2 mm causes a decrease in the intrinsic viscosity and an increase in the constant of the Huggins equation. An increase in the Mave of the polymer structure formation (cross-linking) and a repeated forcing through is conducive to the mechanical breakdown of the macromolecules. It has been established that in mixing together solutions of polymeric substances (starch, gelatine, polyvinyl alcohol, etc.) with high-speed mixers having a rotation speed of over 4000 rpm, a sharp decrease in the intrinsic viscosity [ν] is observed, while the degree of scission increases, with an increase in the rotation speed of the mixer, and also with a decrease in the concentration of the solution.

THE EFFECT OF SOLVENT AND TEMPERATURE ON THE VISCOSITY OF THE POLYSACCHARIDE OF IRISH MOSS AND THE EFFECT OF SOLVENT ON ITS INITIAL GELATION

1946 ◽  
Vol 24b (1) ◽  
pp. 12-19 ◽  
Author(s):  
F. A. H. Rice
Keyword(s):  
Aqueous Solutions ◽  
Intrinsic Viscosity ◽  
Neutral Salt ◽  
Aqueous Extracts ◽  
Chondrus Crispus ◽  
Salt Solutions ◽  
Specific Viscosity ◽  
Effect Of Solvent ◽  
Irish Moss ◽  
Dilute Aqueous Solutions

The viscosity of aqueous extracts of Irish moss (Chondrus crispus) has been found to depend mainly on the concentration of the neutral salts present in the solution. Samples of dialyzed polysaccharide, however, show considerable variation. The relation between the specific viscosity and the concentration in dilute aqueous solutions and formamide is such that ηsp = acv + bcc2, where ηsp is the specific viscosity, cv the concentration, and both a and b are constants. In aqueous solution these constants are decreased by the addition of neutral salts. A rise in temperature causes a decrease in viscosity. This decrease is less rapid for solutions in formamide and aqueous solutions containing neutral salts. The effectiveness of individual salt solutions in promoting a decrease in viscosity coincides with their effect in producing precipitation of the polysaccharide. The order of decreasing effectiveness was: potassium chloride, calcium chloride, sodium chloride. When the concentration of gelose is such that gelation takes place on standing, measurements of viscosity become irregular and are not reproducible. The concentration of gelose at which the regular viscosity measurements are obtained decreases with increasing concentration of neutral salts. The rigidity of the gels so formed also decreases. The firmness of a gel seemingly depends on the concentration and type of neutral salt, as well as on the intrinsic viscosity of the polysaccharide. The intrinsic viscosity is defined as: the limit of the specific viscosity as the concentration approaches zero.

scholarly journals Solution Properties of Combretum Glutinosum (Habeil) Gum

2015 ◽  
Vol 7 (2) ◽  
pp. 49
Author(s):  
M. Awad
Keyword(s):  
Ionic Strength ◽  
Salt Tolerance ◽  
Intrinsic Viscosity ◽  
Distilled Water ◽  
Solution Properties ◽  
Stiffness Parameter ◽  
Chain Stiffness ◽  
Reduced Viscosity ◽  
Gel Fraction ◽  
Optimum Model

The solubility of Combretum glutinosum gum in distilled water ranged from 30 to 40% and gel fraction ranges between 60 to 70%. It was found that the gum solubility increased with increase the pH of solution. The reduced viscosity of Gum Habeil in distilled water was increased with decrease the concentration of gum solution, and this is the a behavior of ionic polysaccharide solutions, for that Huggins and Kraemer equations are incapable to derive the intrinsic viscosity value of aqueous gum solution. Some extrapolated equations such as Fouss, Schulz –Blaschke, Martin, Heller, and Fedors equations used to estimate the optimum model for measurement intrinsic viscosity of this type of gum. The influence of ion types and ionic strength on the viscosity of gum solutions were also determined. The effect of ionic strength on the intrinsic viscosity of Combretum glutinosum gum was used to determine the salt tolerance value and the chain stiffness parameters of this type of gum. This study exhibited that the values of chain stiffness parameter (B), and salt tolerance (S) of deacetylated gum in the range of 0.0574 to 0.0700, and0.083 to 0.101 dl× M1/2 / g respectively.

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