188. The effect of commercial sterilization on the nutritive value of milk. V. The effect of commercial sterilization on the vitamin C of milk

1938 ◽  
Vol 9 (2) ◽  
pp. 185-187 ◽  
Author(s):  
K. M. Henry ◽  
S. K. Kon
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Chemical Method ◽  
Nutritive Value ◽  
Raw Milk ◽  
Sterilized Milk

1. Fifteen samples of raw and fifteen samples of commercially sterilized milk from the same bulk were analysed for vitamin C by the chemical method (titration with dichlorophenol-indophenol).2. The raw milk contained on an average 1·83 mg./100 ml. of total (reduced and reversibly oxidized) ascorbic acid. The corresponding figure for sterilized milk was 1·03 mg./100 ml., a loss of 43% of the original value.3. Storage of the sterilized milk for a period of 4·6 weeks resulted in a further reduction equivalent to about 30%.

173. The effect of commercial sterilization on the nutritive value of milk. III. Effect on the vitamin A and carotene content of milk

1938 ◽  
Vol 9 (1) ◽  
pp. 17-21 ◽  
Author(s):  
A. E. Gillam ◽  
K. M. Henry ◽  
S. K. Kon ◽  
P. White
Keyword(s):  
Heat Treatment ◽  
Vitamin A ◽  
Nutritive Value ◽  
Colorimetric Method ◽  
Raw Milk ◽  
Carotene Content ◽  
Lovibond Tintometer ◽  
Ether Extraction ◽  
Sterilized Milk

1. The vitamin A and carotene content of raw milk have been compared with that of milk from the same bulk after it had been commercially sterilized.2. For this purpose the fat was obtained by ether extraction from eleven samples of raw milk and from eleven corresponding samples of sterilized milk. As the sterilized milk had been previously homogenized it was not possible to churn it.3. The vitamin A and carotene content was estimated by colorimetric (Lovibond tintometer) and by spectrophotometric tests.3. The vitamin A and carotene content was estimated by colorimetric (Lovibond tintometer) and by spectrophotometric tests.4. The results showed that the efiect of the heat treatment was negligible, neither method demonstrating a loss in vitamin A, while for carotene only the colorimetric method indicated a loss of about 2 %.5. The vitamin A and carotene contents of sterilized milk were not decreased after storage for several weeks in a cool dark place.

scholarly journals The effect of selected substances on the stability of standard solutions in voltammetric analysis of ascorbic acid in fruit juices

2019 ◽  
Vol 17 (1) ◽  
pp. 655-662
Author(s):  
Radosław Kowalski ◽  
Artur Mazurek ◽  
Urszula Pankiewicz ◽  
Marzena Włodarczyk-Stasiak ◽  
Monika Sujka ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Room Temperature ◽  
Nutritive Value ◽  
Fruit Juices ◽  
Optimum Concentration ◽  
Voltammetric Analysis ◽  
The Stability ◽  
Standard Solutions

AbstractThe objective of the study was to identify suitable additives stabilizing standard solutions of ascorbic acid (AA) that would not cause interference in the analytical process with the use of voltammetry in the determination of the AA content in food products. In addition, the effect of various conditions of storage of selected fruit juices and drinks on the concentration of vitamin C was studied. The study demonstrated that AA degradation was inhibited the most effectively by tartaric acid and its optimum concentration was set to 200 mg L-1. Analysis of selected fruit juices stored in various temperature conditions confirmed that an elevation of temperature and extension of the time of storage caused a decrease in the content of vitamin C in the analyzed samples, while closing the packages caused a limitation of the changes in concentration of this vitamin. On the basis of literature data and of the results obtained in the present study it can be concluded that fruit juices should be stored at a temperature lower than room temperature to retain their nutritive value.

171. The effect of commercial sterilization on the nutritive value of milk. IIa. biological value and digestibility of the proteins (nitrogen) of milk

1938 ◽  
Vol 9 (1) ◽  
pp. 6-11 ◽  
Author(s):  
K. M. Henry ◽  
S. K. Kon
Keyword(s):  
Heat Treatment ◽  
Nutritive Value ◽  
Statistical Tests ◽  
Raw Milk ◽  
Biological Value ◽  
True Digestibility ◽  
The Difference ◽  
Sterilized Milk

1. The biological values and true digestibilities of the proteins of raw and commercially sterilized milks from the same bulk have been compared on rats by the method of Mitchell.2. For raw milk a biological value of 84·3 and a true digestibility of 96·4 were obtained, while the figures for sterilized milk were 79·1 and 95·3 respectively.3. Statistical tests showed that the difference in true digestibility was not significant but that the lowering of the biological value by about 6% could be ascribed to the effect of the heat treatment, the odds against chance factors being 625: 1.

189. The effect of commercial sterilization on the nutritive value of milk. VI. Comparison of the total nutritive value of raw and commercially sterilized milks

1938 ◽  
Vol 9 (2) ◽  
pp. 188-206 ◽  
Author(s):  
K. M. Henry ◽  
E. W. Ikin ◽  
S. K. Kon
Keyword(s):  
Nutritive Value ◽  
Basal Diet ◽  
Raw Milk ◽  
Cane Sugar ◽  
Male Rats ◽  
Limiting Factor ◽  
Protein Energy ◽  
Preceding Experiment ◽  
The Difference ◽  
Sterilized Milk

1. The effect of commercial sterilization on the total nutritive value of milk was studied in five separate experiments.2. In the first experiment raw and sterilized milks supplemented with minerals were given in equal amounts to pairs of litter-mate male rats. No differences were found in the growth performance of the rats, but the rats on sterilized milk consumed it more readily than their mates on raw milk. This difference was statistically significant.3. Rats getting limited but equal amounts of milk in addition to a basal diet which supplied only protein, energy and minerals grew better on raw than on sterilized milk.4. When the basal diet contained in addition 5% brewer's yeast and the milk intakes were the same as in the previous experiment no difference was found between the two groups.5. Rats receiving raw milk to which 15 g. of cane sugar was added per 100 ml. grew better than rats receiving equal quantities of similarly treated sterilized milk.6. Rats given raw milk containing 30 g. per 100 ml. of sugar grew as well as the rats on sterilized milk in the preceding experiment, but rats receiving similarly treated sterilized milk took much less milk than the raw milk rats, grew very poorly and some of them developed symptoms of beri-beri.7. The difference between raw and sterilized milk is discussed and it is concluded that in these experiments on the total nutritive value of milk vitamin B1 was the first limiting factor of sterilized milk.

Observations on the use of 2,4-dinitrophenylhydrazine and of 2,6-dichlorophenolindophenol for the determination of vitamin C in raw and in heat-treated milk

1970 ◽  
Vol 37 (1) ◽  
pp. 29-45 ◽  
Author(s):  
Joyce Toothill ◽  
S. Y. Thompson ◽  
J. Edwards-Webb
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Ascorbic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Dehydroascorbic Acid ◽  
Heat Treated ◽  
Sterilized Milk ◽  
Layer Chromatography

SummaryA study has been made of methods using 2,4-dinitrophenylhydrazine (DNPH) or 2,6-dichlorophenolindophenol (DCP) for the determination of vitamin C (ascorbic acid+dehydroascorbic acid) in raw, UHT processed, evaporated and sterilized milk.Interfering substances were not detected in milk that had received a heat treatment no more severe than 145°C for 4 s (UHT process), so that either reagent could be used.With more drastic heat treatment, interfering substances were formed and only the DNPH method with column and thin layer chromatography of the DNPH derivatives was specific for vitamin C. With in-bottle sterilized milk, the values for ascorbic acid were (in mg/100 ml) 1·16 (DCP method with H2S reduction); 0·58 (DCP method with Escherichia coli reduction); 0·64 (DNPH method); 0·33 (DNPH method combined with chromatography).In our experience the DNPH method combined with chromatography of the derivatives is highly specific for vitamin C and should be used to check the results obtained by other and simpler methods.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

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