Gas chromatography was applied to 8 food preservatives and 13 food antioxidants. The results obtained were as follows: 1. The use of columns with 5% DGS plus 1% phosphoric acid, 10% NGS plus 1% phosphoric acid and 5% Tween 80 plus 1% phosphoric acid as liquid phase permits rapid analysis of food preservatives such as sorbic acid, dehydroacetic acid, benzoic acid, methylnaphthoquinone and alkyl p-hydroxybenzoate. 2. The trimethylsilyl derivatives of food antioxidant such as alkyl gallate, ethyl protocatechuate, guaiac resin can be determined by use of packed columns with 1.5% SE-30, 0.7% QF-1, 1.0% NGS.
Acute administration of Tropolone-Na was performed on dd-strain mice and Wistarstrain rats. It was found that LD50 in mice was 231mg/kg in subcutaneous administration and 312mg/kg in oral administration, LD50 in rats was 175mg/kg in subcutaneous administration and 212mg/kg in oral administration. Tropolone-Na is potent and rapid-acting, and almost all deaths occurred on and about 12 hours after the administration. On the other hand, it is rapidly excreted, and all animals, who survived 24 hours, were regarded to be in normal activities. Histological examination revealed there were remarkable degenerative necrosis in the liver but only mild changes in the other organs.
Subacute administration of Tropolone-Na was performed on dd-strain mice and Wistarstrain rats, and the following results were obtained. 1) The maximal tolerance dose to a mouse is presumed to be 48mg/kg or over. 2) The minimal toxic dose to a mouse is 26-48mg/kg. 3) The histological changes are most significant in the liver and kidneys in mice. 4) The maximal tolerance dose to a rat is presumed to be 36mg/kg or over. 5) The minimal toxic dose to a rat is 18-36mg/kg. 6) The histological changes, though mild, are seen most frequently in the liver and kidneys in rats. 7) When Tropolone-Na is used to maintain freshness of fishery products, it is regarded to be perfectly safe to men. It is, however, not always safe when for boiled fishpaste.
Selected 8 kinds of naphthol-sulfonic acids were classified into following 4 groups in accordance with those chemical structures. Group 1. H-acid (8-hydroxy-naphthylamine-3, 6-disulfonic acid) and Chromotropic acid (1, 8-naphthalenediol-3, 6-disulfonic acid) Group 2. R-acid (2-naphthol-3, 6-disulfonic-acid) and G-acid (2-naphthol-6, 8-disulfonic acid) Group 3. Schaeffer acid (2-naphthol-6-sulfonic acid) and Crocein acid (2-naphthol 8-sulfonic acid) Group 4. NW acid (1-naphthol-4-sulfonic acid) and oxy-L-acid (1-naphthol-5-sulfonic acid) High-voltage paper electrophoresis was carried out for the separation of naphthol-sulfonic acids mentioned above. Sørensen buffer (10% propylene glycol sol.) was used as an electrolyte, the potential gradient was 50V/cm and separation time 30 minutes. It was revealed that it was necessary to use the most suitable pH buffer for the separation of isomers of each group. These pH buffers were as follows: Group 1. Phosphate buffer (pH 6) Group 2. Borate buffer (pH 10) Group 3. Citrate or Phosphate buffer (pH 5-7) Group 4. Borate buffer (pH 10)
Various isomers are always present in commercial samples of R-, G- and Schaeffer acids. According to our experiments, high-voltage paper electrophoresis seems to provide the best separation and determination of these isomers on the micro scale. The procedure was as follows. Known quantities of samples (ca. 100g) were submitted to paper electrophoresis by using borate buffer (pH 10) as an electrolyte, in the condition of 75V/cm. As soon as 10 minutes of separation time elapsed, the separated zones were cut off wet, extracted seperately with borate buffer solution (pH 10) as rapidly as possible on the water bath, the quantities of dyes in extracted fractions were fluorophotometrically determined in comprison with standard naphthol-sulfonic acids. Commercial samples were examined according to this method. The results are shown in Table 5.
The assay method of “The Japanese Standards of Food Additives, 1st. Ed., 1960”, is as follows: Dissolve about 0.5g of nitrofurazone, dried at 105° for 1 hour and accurately weighed, in aldehyde-free alcohol to produce a 1000ml solution, To 20ml of the solution add sufficient water to make the colume to 100ml. To 5ml of the solution add 4ml of aldehyde-free alcohol, and dilute to 100ml with water. Determine the absorbance A of this solution in a 1cm cell, at a wave length of 375mμ. Calculate the purity of nitrofurazone by the following formula. Correct the result by the control test. Content=A/0.398×500/Weight of sample (mg) ×100 (%) However, the data obtained by this method are not always precise. In this report, the new method is described, in which another compound of high purity listed in the official book is adopted as the control standard substance. In this case, p-nitrophenylhydrazine is suitable for this purpose. The purity of nitrofurazone is calculated by the following formula. Content (%) =Absorbance in ca. 5ppm nitrofurazone in 1% glycine aqueous solution/Absorbance in ca. 5ppm p-nitrophenylhydrazine in 1% glycine aqueous solution×0.901×Weight (mg) of p-nitrophenylhydrazine/Weight (mg) of the Sample By this method, the discrepancy of absorbances due to difference in kinds of instruments or cells is able to be compensated, and the results of determination are almost constant.
The wave length of maximum absorption (λmax.) of sorbic acid and its molar absorbancy index (∈) change depending upon pH of solutions. However, they were fixed and constant below pH 2.5 and since it was easy to keep pH below 2, absorbancy was read at a pH range of 0.5 to 2. According to this method, the two calibration curves formed straight lines between 0.5μg/ml and 3.0μg/ml. E264-E275 seemed, however, to provide better accuracy and precision for calibration and determination than the other because while the backgrounds at 264mμ and 275mμ, due to impurities from prunes, were too large to be neglected, there was little difference between them.
BHT is a very effective antioxidant for fats and oils. Its combination with other antioxidants is often used. That has indicated the need for a specific and simple method for its quantitative determination. The method presented in this paper is based on separation of BHT from fat or oil by steam distillation, extraction with carbone tetrachloride, application of thin layer chromatography, color reaction of spots with phosphomolybdic acid and measurement of the spot areas. There was a linear relationship between the square root of the spot area and the logarithm of the concentration of BHT (0.25 to 5.0mg/ml). The per cent recovery of BHT from edible oils (100 to 300ppm) was 98±10per cent.
A variety of refined pyroligneous liquors and their preparations has been used for giving characteristic smoked flavour to meat, fish, and other food preducts. Eighteen commercial samples were analyzed on the harmful constituents, i. e., phenolic substances (I), formaldehyde (II), methanol (III), lead (IV), zinc (V) and arsenic (VI). (I) were determined as phenol by colorimetric method with 4-aminoantipyrine, and results were between 0.008 and 0.675%. Nash and Dimedone method were used for determination of (II), and the contents were 0.60-47.50mg% by the former and 1.11-42.23mg% by the latter. After separated from (II) using Amberlite CG-400 (HSO3-) 1×8cm column, (III) was determined following the procedure of the A.O.A.C. The contents were between 0.007 and 1.600%. 0-14.2ppm (IV), 0-50.4ppm (V), and 0-3.5ppm (VI) were founded by the usual Dithizone method.