Moisture--Modified Vacuum-Oven Method

2009 ◽  
Author(s):  
AACC Technical
Keyword(s):  
Oven Method ◽  
Vacuum Oven

Moisture Analysis of Freeze-Dehydrated Cottage Cheese

1967 ◽  
Vol 50 (6) ◽  
pp. 1279-1283
Author(s):  
James L Fowler ◽  
Charles H Coleman
Keyword(s):  
High Capacity ◽  
Cottage Cheese ◽  
Oven Method ◽  
Vacuum Oven ◽  
Drying Time ◽  
Alternative Method ◽  
Moisture Analysis ◽  
Government Laboratories

Abstract A large number of samples of dehydrated cottage cheese are received by government laboratories for moisture analysis, and the apparatus for performing the test by the prescribed method lacks adequate capacity to handle them. Therefore, an experiment was designed to test whether analysis by an alternative method making use of high capacity apparatus would give comparable results. It was concluded that the mechanical convection air oven, 100—102°C, 16—18 hr drying time, did not give results comparable to the specified vacuum oven method

Determination of Water in Molasses by Karl Fischer Method

1971 ◽  
Vol 54 (5) ◽  
pp. 1231-1235
Author(s):  
Boris Kviesitis
Keyword(s):  
Collaborative Study ◽  
Oven Method ◽  
Vacuum Oven ◽  
Water Determination ◽  
Cane Molasses ◽  
Karl Fischer ◽  
Karl Fischer Method ◽  
Fischer Method

Abstract Successful use of the method depends on several factors, one of which is the size of the sample because it affects the result of the titration. In this study, 2 sizes of cane molasses samples were tested and the results were compared with those from the vacuum oven method. The use of larger samples with or without the addition of surfactant increased the precision of the analysis. It is recommended that the Karl Fischer method for water determination in molasses and sugar sirups be subjected to collaborative study.

Moisture Determination on Fertilizer and Superphosphate

1963 ◽  
Vol 46 (4) ◽  
pp. 592-595
Author(s):  
Robert D Shannon
Keyword(s):  
Quality Control ◽  
Moisture Content ◽  
Comparative Studies ◽  
Raw Materials ◽  
Moisture Determination ◽  
Triple Superphosphate ◽  
Oven Method ◽  
Vacuum Oven

Abstract Studies have been conducted on the moisture content of fertilizers by the vacuum oven and 100° oven methods. The fertilizers studied include ExDen superphosphate, cured superphosphate, triple superphosphate, samples of 0- 20-0 fertilizer, and selected raw materials. The vacuum oven is shown by comparative studies with the 100° oven method to be the more satisfactory for quality control.

RAPID DETERMINATION OF MOISTURE IN GRAIN: III. CALIBRATION AND COMPARISON OF ELECTRICAL MOISTURE METERS WITH VACUUM OVEN FOR AMBER DURUM WHEAT, BARLEY AND OATS

1934 ◽  
Vol 11 (5) ◽  
pp. 547-563 ◽  
Author(s):  
W. H. Cook ◽  
J. W. Hopkins ◽  
W. F. Geddes
Keyword(s):  
Durum Wheat ◽  
Spring Wheat ◽  
Rapid Determination ◽  
Limited Range ◽  
Oven Method ◽  
Vacuum Oven ◽  
Hard Red Spring Wheat ◽  
Significant Difference ◽  
Moisture Basis ◽  
Limited Moisture

The previous study has been extended to include durum wheat, barley and oats. The hand-operated Tag-Heppenstall meter was found to be unsatisfactory with these grains, as they would not feed into the roller electrodes in a suitable manner. The Burton-Pitt gave erratic results with these grains and it was only possible to calibrate this meter over a limited moisture range, and even over this range it was more inaccurate than the other meters. Qualitatively the calibration curves for these three grains, in the Limbrick and motor Tag-Heppenstall, were similar to those previously obtained with hard red spring wheat. The actual resistance and the slope of the curves were, however, somewhat different for the different grains. The standard error of prediction shows that the motor-operated Tag-Heppenstall was the most accurate meter for use with durum wheat and barley, while the Limbrick was superior with oats. With the limited number of samples available it was impossible to detect any significant difference between the temperature coefficients, in any particular meter, of the different grains. When converted to a moisture basis the correction factors were practically the same as for hard red spring wheat.The results from the entire investigation show that the Brown-Duvel method is more accurate than the 130 °C. air oven method with all grains studied. The motor-operated Tag-Heppenstall meter is as accurate as the Brown-Duvel with hard red spring wheat, over the moisture range 11.0 to 17.0%, and is superior to the air oven method over this limited range. Otherwise the rapid analytical methods are more accurate than any of the moisture meters tested with any of the grains. The meters fall in the following order of decreasing accuracy over the moisture range 11.0 to 17.0%:–with hard red spring wheat; motor Tag-Heppenstall, Limbrick, hand Tag-Heppenstall, Burton-Pitt and Davies: with durum wheat and barley; motor Tag-Heppenstall, Limbrick and Burton-Pitt: and with oats; Limbrick, Burton-Pitt and motor Tag-Heppenstall. Where a meter is not mentioned no tests were made, the instrument having been omitted because it gave no promise of practical utility.

MEASURING THE SOLIDS CONTENT OF HONEY AND OF STRAWBERRY JAM WITH A HAND REFRACTOMETER

1949 ◽  
Vol 27f (3) ◽  
pp. 99-103 ◽  
Author(s):  
Jesse A. Pearce ◽  
Suzanne Jegard
Keyword(s):  
Standard Error ◽  
Oven Method ◽  
Vacuum Oven ◽  
Routine Inspection ◽  
Solids Content

A hand refractometer may be useful for routine inspection of the solids content of honey, and of strawberry jam containing added pectin. For 76 pairs of determinations on honey,[Formula: see text]with a standard error of prediction of ± 0.4%; for 116 pairs of determinations on the jam,[Formula: see text]with a standard error of prediction of ± 0.3%, where y is the per cent solids by the A.O.A.C. vacuum-oven method and x is the reading on the hand refractometer. A standard error of ± 0.5% was observed for determinations by the vacuum-oven method, and of ± 0.4% for determinations with the hand refractometer.

The Vacuum Oven Method for Free Water in Fertilizers. I. Ruggedness Tests. II. Collaborative Study

1964 ◽  
Vol 47 (6) ◽  
pp. 1040-1047
Author(s):  
Joseph H Caro ◽  
Noiibert A Heinly
Keyword(s):  
Collaborative Study ◽  
Free Water ◽  
Oven Method ◽  
Vacuum Oven ◽  
Temperature Range ◽  
Allowable Temperature

Abstract Ruggedness tests revealed that the only experimental variable to which results in the vacuum oven method were sensitive was the oven temperature. The allowable temperature range within the oven chamber was less than 5°C. The range was specified as 3°C in the procedure which was studied collaboratively. The collaborative results showed the vacuum oven method to be as precise as the official vacuum desiccation method. Since it is also more rapid, the vacuum oven method was recommended for adoption as official, first action.

Modified Karl Fischer and Vacuum Oven Moisture Methods for Cheese Products: Comparative Study

1979 ◽  
Vol 62 (4) ◽  
pp. 828-831
Author(s):  
Genevieve L Christen ◽  
Gary H Richardson
Keyword(s):  
Comparative Study ◽  
Oven Method ◽  
Vacuum Oven ◽  
Karl Fischer ◽  
High Coefficient ◽  
Rapid Methods ◽  
Karl Fischer Method ◽  
The Mean ◽  
Cheese Products ◽  
Fischer Method

Abstract In a modified Karl Fischer method, methanolchloroform (1+1) was used to extract moisture from cheese after homogenization in an automatic titrimeter. The mean coefficient of variance was high (0.82%) for the modified apparatus as determined by the values obtained during computation of the Karl Fischer factor. Variance from other sources in the assay was not significant. Comparative data on 6 different cheese samples produced within-day coefficient of variance values from 0.46 to 0.85%, following discard of outlying data, compared to 0.12 to 0.30% for within-day values obtained using the official vacuum oven method. A sample could be assayed in 7 min. The apparatus costs less than equipment required for some rapid methods; however, solvent and reagent costs, high coefficient of variance values, and the need for expensive reagents suggest that this approach is impractical for extracting moisture from cheese products.

Moisture in Dried Vegetables and Spices

1966 ◽  
Vol 49 (4) ◽  
pp. 726-730 ◽  
Author(s):  
Bobby R Eader
Keyword(s):  
Near Infrared ◽  
Collaborative Study ◽  
Oven Method ◽  
Vacuum Oven ◽  
Karl Fischer ◽  
Karl Fischer Method ◽  
Infrared Method ◽  
Dried Vegetables ◽  
Fischer Method

Abstract A collaborative study was conducted to compare the near-infrared spectrophotometric method and a Karl Fischer volumetric method with a vacuum oven method for the determination of moisture. Results by the near-infrared method were as accurate as and more rapid and specific than the vacuum oven method. Results by the Karl Fischer method were not as satisfactory; more study is needed to improve the precision of the method.

RAPID DETERMINATION OF MOISTURE IN GRAIN: I. COMPARISON OF 130 °C. AIR OVEN AND BROWN-DUVEL METHODS WITH VACUUM OVEN METHOD

1934 ◽  
Vol 11 (3) ◽  
pp. 264-289 ◽  
Author(s):  
W. H. Cook ◽  
J. W. Hopkins ◽  
W. F. Geddes
Keyword(s):  
Moisture Content ◽  
Durum Wheat ◽  
Spring Wheat ◽  
Standard Error ◽  
Systematic Bias ◽  
Consistent Estimate ◽  
Sampling Errors ◽  
Oven Method ◽  
Vacuum Oven ◽  
Hard Red Spring Wheat

Some 300 samples of hard red spring wheat, 50 of amber durum wheat and 75 each of oats and barley, covering the entire moisture range of commercial importance, were employed in the comparisons. Provision was made for statistical estimation of sampling errors, errors of method and errors of observation. A two-stage drying procedure was employed for the vacuum oven determinations which were taken as the reference standard. Sampling errors, average difference between identical ovens and errors due to daily fluctuations were all larger than the standard deviation of duplicates ("experimental error"), the sampling error being the largest.A comparison of the Hobart and Wiley grinders shows the latter to be superior for preparing wheat for the 130 °C. air oven determination. The air oven consistently underestimates the moisture content of all the grains tested, as compared with the vacuum oven, the deficit increasing with the actual moisture content. This systematic bias may be eliminated by means of a linear correction equation. After allowing for the observed sampling errors and errors of the vacuum oven determination, the net standard error of prediction with the air oven using a Wiley mill is, with hard red spring wheat 0.24%, with amber durum wheat 0.12%, with barley 0.20% and with oats 0.20% moisture.The Brown-Duvel method also underestimates the moisture content, this deficit also increasing with the actual moisture content in the case of spring and amber durum wheat. After applying a correction equation to eliminate the systematic bias, the net standard error of prediction of moisture by this method was found to be: with hard red spring wheat 0.16%, with durum wheat 0.09%, with barley 0.12% and with oats 0.13%. The Brown-Duvel method, therefore, when carefully operated makes possible a more consistent estimate of the actual moisture content, as determined by the vacuum oven, than does the 130 °C. air oven method. As with the vacuum oven, both the 130 °C. air oven and the Brown-Duvel appear to be subject to slight variations affecting all the determinations made on any particular day.

Sign in / Sign up

Export Citation Format

Share Document