Rapid Screening Method for Alkaline Phosphatase Activity in Cheese: Collaborative Study

1978 ◽  
Vol 61 (5) ◽  
pp. 1035-1037
Author(s):  
Dick H Kleyn
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Collaborative Study ◽  
Screening Method ◽  
Rapid Screening ◽  
Butanol Extract ◽  
Rapid Screening Method

Abstract The method developed for determining alkaline phosphatase activity in cheese, in which phenolphthalein monophosphate is used as the substrate, was collaboratively studied. A 7.5% butanol extract of cheese is reacted with phenolphthalein monophosphate; phenolphthalein is released and yields a red solution that is compared visually with a standard (s) prepared from the same extract. Seven collaborators analyzed 8 samples of cheese, in duplicate, by the screening method and Scharer I method. Of the 208 observations returned, only 4 were incorrect. The alkaline phosphatase method has been adopted as official first action.

Collaborative Study of Alkaline Phosphatase Activity in Filter Paper Disks Impregnated with Skim Milk: Positive Control Sample

1982 ◽  
Vol 45 (2) ◽  
pp. 112-114 ◽  
Author(s):  
G. K. MURTHY ◽  
J. T. PEELER
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Filter Paper ◽  
Room Temperature ◽  
Collaborative Study ◽  
Control Sample ◽  
Skim Milk ◽  
Positive Control ◽  
Colorimetric Test

The rapid colorimetric test was used in a collaborative study to determine alkaline phosphatase activity in filter paper disks impregnated with skim milk then dried and stored for several months at room temperature. Five samples of filter paper disks (0 to 6 μg phenol/disk) in duplicate were sent to six collaborators for analysis. Computations of analytical and analyst errors showed variations of 22.2 to 48.8%. Most of the variations were due to differences among analysts, but some were partly due to differences in the slopes of the calibration curves (a = 0.05 level) they prepared at the time of analysis. Collaborator's performance was evaluated by comparing % correct results that were positive (negative) with the expected results. About 95% of the samples were correctly analyzed.

Collaborative Study of the Extraction of Plant Sterols from Adulterated Butter Oil Using a Digitonin-impregnated Celite Column

1970 ◽  
Vol 53 (3) ◽  
pp. 535-538
Author(s):  
Denis E Lacroix
Keyword(s):  
Liquid Chromatography ◽  
Vegetable Oil ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Screening Method ◽  
Rapid Screening ◽  
Gas Liquid Chromatography ◽  
Butter Oil ◽  
Average Coefficient ◽  
Rapid Screening Method

Abstract A rapid screening method for the analysis of the phytosterol, β-sitosterol, in butter oil adulterated with vegetable oil has been studied collaboratively. The sterols are removed from the adulterated butter oil by passing the sample through a digitonin-impregnated Celite 545 column, eluting the sterols with dimethyl sulfoxide, and analyzing the eluate for β-sitosterol by gas-liquid chromatography using a 3% JXR column. The average coefficient of variation for those samples containing more than 4 mg β-sitosterol/100 g adulterated butter oil is 12.6%. Therefore, β-sitosterol can be used as an index to qualitatively detect vegetable oil adulteration of butter oil.

UTILIZATION OF PHENOLPHTHALEIN MONOPHOSPHATE TO TO DETERMINE THE PHOSPHATASE ACTIVITY OF MILK1

1972 ◽  
Vol 35 (7) ◽  
pp. 405-409 ◽  
Author(s):  
Dick H. Kleyn
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Rapid Method ◽  
Alkaline Phosphatase Activity ◽  
Collaborative Study ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
New Method ◽  
Chocolate Milk ◽  
Positive Correlations

The properties of alkaline phosphatase as it exists in milk are considered. The more common methods of measuring alkaline phosphatase activity in milk are briefly reviewed, especially those employing substrates possessing “built-in” indicators which produce a chromogen directly upon hydrolysis. The visual procedure employing phenolphthalein monophosphate as the substrate is given. The sensitivity of this method is shown to be far greater than that of the Scharer I (Rapid) method. Results of an AOAC Collaborative study demonstrated that the method yields results that are as precise and either as accurate as or more accurate than those obtained by the Scharer I (Rapid) method. The quantitative spectrophotometric procedure employing the above substrate is presented. Comparison of this method with the Scharer modified spectrophotometric method on milk revealed correlation coefficients (Scharer method: 0.998 and modified new method 0.991) showing very little difference in the positive correlations of absorbance values and % raw milk. For chocolate milk, the values were 0.990 and 0.990 for the respective methods. Collaborative study of this method has demonstrated that the random error of the modified new method is almost twice that of the Scharer technique while the systematic error is only about one-fourth of the latter method.

Rapid Screening Method for Chick Edema Factor in Fats and Fatty Acids: 1967 Collaborative Study

1968 ◽  
Vol 51 (4) ◽  
pp. 940-942
Author(s):  
G R Higginbotham ◽  
John Ress ◽  
David Firestone
Keyword(s):  
Sulfuric Acid ◽  
Petroleum Ether Extract ◽  
Collaborative Study ◽  
Screening Method ◽  
Rapid Screening ◽  
Sulfuric Acid Treatment ◽  
Edema Factor ◽  
Capture Method ◽  
Rapid Screening Method ◽  
Chromatographic Peaks

Abstract A recently proposed improved rapid screening method for chick edema factor in fats was studied collaboratively by ten laboratories. The new procedure, a modification of the official electron capture method, reduces sample cleanup time by replacing the saponification step of the original procedure with a preliminary sulfuric acid cleanup step. Subsequent cleanup involves alumina column chromatography of the petroleum ether extract from sulfuric acid treatment, and gas chromatographic analysis at 200 °C of a specific polar alumina fraction. Gas chromatographic peaks with retention times vs. aldrin between 10 and 25 indicate the presence of chick edema factor. It is recommended that the modified procedure be adopted as official, first action.

Rapid Determination of Alkaline Phosphatase Reactivation

1977 ◽  
Vol 60 (6) ◽  
pp. 1389-1391
Author(s):  
Dick H Kleyn ◽  
Chia-Lu Ho
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Rapid Determination ◽  
Screening Method ◽  
Raw Milk ◽  
Relative Increase ◽  
Negative Results

Abstract A study was conducted to determine the feasibility of using the qualitative screening method specifying phenolphthalein monophosphate for differentiating reactivated and residual alkaline phosphatase activity. The relative increase in activity of the enzyme in the presence of MgCl2 serves to distinguish reactivated and residual alkaline phosphatase activity. Ten samples each of pasteurized (172°F for 24 sec), sterilized (about 300°F for a minimum of 2 sec) half-and-half and heavy cream were analyzed. Most samples yielded negative results initially but demonstrated activity after incubation 1 hr at 34°C. The average values, in terms of + marks, for the half-and-half and heavy cream in samples without MgCl2 were <1 and 2.4, respectively ; for samples treated with MgCl2, the values were 2.18 and 4.6, respectively, indicating reactivated phosphatase activity. In samples containing various levels of raw milk, the activity observed in the diluted, Mg2+-containing samples was less than in the undiluted samples containing no Mg, indicating residual phosphatase activity.

LEUCOCYTE METABOLISM IN PREGNANCY

1960 ◽  
Vol XXXV (IV) ◽  
pp. 575-584 ◽  
Author(s):  
C. Borel ◽  
J. Frei ◽  
A. Vannotti
Keyword(s):  
Alkaline Phosphatase ◽  
Oxygen Consumption ◽  
Pregnant Women ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Lactate Production ◽  
Glucose Consumption ◽  
In Pregnancy

ABSTRACT Enzymatic studies, on leucocytes of pregnant women, show an increase of the alkaline phosphatase activity and a decrease of the glucose consumption and lactate production, as well as of proteolysis. The oxygen consumption, with succinate as substrate, does not vary.

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