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.

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.

LIQUID AND FROZEN EGG: II. METHODS OF DETERMINING SOLIDS CONTENT OF LIQUID AND FROZEN EGG

1946 ◽  
Vol 24f (3) ◽  
pp. 183-190
Author(s):  
C. G. Lavers ◽  
Jesse A. Pearce
Keyword(s):  
Refractive Index ◽  
Specific Gravity ◽  
Ammonium Hydroxide ◽  
Oven Method ◽  
Vacuum Oven ◽  
Shell Eggs ◽  
Gravity Measurements ◽  
Solids Content

Solids content of liquid egg prepared from shell eggs having different histories was measured by the official A.O.A.C. vacuum oven method and compared with measurements of specific gravity and refractive index. Specific gravity measurements were the least satisfactory, but may provide a rough check on solids content. Refractive index measurements following treatment with ammonium hydroxide were a more satisfactory measure of solids content than the same measurement on liquid egg after treatment with trypsin solution.Relations between the solids content of defrosted frozen egg and unfrozen liquid egg and refractive index, as determined with a Zeiss sugar refractometer and with a hand sugar refractometer, were calculated for the method involving the addition of ammonium hydroxide. The relation, solids–refractive-index, for unfrozen liquid egg differed from the relation for frozen egg. However, the method provided a rapid, convenient, and accurate means for determining solids content.

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

Comparison of Two Methods for Determination of Total Solids Content of Milk: Collaborative Study

1989 ◽  
Vol 72 (5) ◽  
pp. 712-718 ◽  
Author(s):  
Jenny L Clark ◽  
David M Barbano ◽  
Chapman E Dunham
Keyword(s):  
Collaborative Study ◽  
Raw Milk ◽  
Preliminary Evaluation ◽  
Oven Method ◽  
Total Solids ◽  
Relative Standard ◽  
Aoac Method ◽  
Standard Deviations ◽  
Forced Air ◽  
Solids Content

Abstract Ten laboratories analyzed 9 pairs of blind duplicate raw milk samples for total solids. A direct forced air oven method (4 h at 100°C) and a modification of the AOAC predry method (16.032) were used. Preliminary evaluation of the modified AOAC method indicated that blank determinations were necessary. Total solids content ranged from 12.0 to 14.6%. Average repeatability standard deviations (sr) of the direct forced air oven and modified AOAC methods were 0.019 and 0.017, respectively. Average reproducibility standard deviations (SR) of the direct forced air oven and the modified AOAC methods were 0.042 and 0.047, respectively. Average repeatability relative standard deviations (RSDr) for the direct forced air oven and the modified AOAC methods were 0.149 and 0.136%, respectively; average reproducibility relative standard deviations (RSDR) were 0.327 and 0.370%, respectively. Mean repeatability values (r) and reproducibility values (R) were 0,054 and 0.118 for the direct forced air oven method and 0.049 and 6.133 for the modified AOAC method, respectively. The mean test result of the direct forced air oven method (12.7293%) was comparable to that for the modified AOAC method (12.7273%). The modification of AOAC method 16.032 and the direct forced air oven method have been approved interim official first action.

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.

Microwave Oven Drying Determination of Total Solids in Processed Tomato Products: Collaborative Study

1985 ◽  
Vol 68 (6) ◽  
pp. 1081-1083
Author(s):  
Henry B Chin ◽  
John R Kimball ◽  
Joyce Hung ◽  
Bradford Allen
Keyword(s):  
Collaborative Study ◽  
Microwave Oven ◽  
Drying Method ◽  
Vacuum Oven ◽  
Oven Drying ◽  
Total Solids ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
Tomato Products ◽  
Solids Content

Abstract Fourteen laboratories analyzed 7 samples of tomato products with total solids content ranging from 6.5 to 40.2%. Samples were analyzed directly with the exception of samples with solids contents greater than 15%, which were diluted with water (1 + 1 for up to 30% solids and 1 + 3 for greater than 30% solids). The 2-4 g samples were dried at 100% power for 4 min. The results of the collaborative study showed good repeatability and reproducibility: 5„ = 0.16 (CV = 0.46%) and S, = 0.36 (CV = 1.06%) for the higher solids samples and S„ = 0.37 (CV = 3.76%) and Sx = 0.14 (CV = 1.41%) for samples with total solids up to 15%. Results were compared with those obtained using vacuum oven drying. No difference was seen in the results by the 2 methods at the 95% level of confidence. The microwave oven drying method has been adopted official first action as an alternative to the vacuum oven drying method for total solids.

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