Biogenesis of anthocyaains .. 3. Hethods used for isolation of anthooyanins. «. a. As piorate b« As lead salt c. Chromatographic techniques .' 4. Methods used for identification of anthocyanins. a. Color changes of anthocyanins b. Characteristic color reactions and distribution between immiscible solvents, 0* Absorption spectra 12 d. Identity of pigments in grapes 13 5. Methods used for separation of anthocyanins.. . a. Dialysis b. Distribution in immiscible solvents ... c. Chromatographic techniques.. (1) Solid columns ..16 (2) Partition ohrosnatographyfilter paper strips d. Ion exchange materials 6. Methods used for estimation of anthocyanins.. «

APPENDIXSix rats were fed for 6 days a diet containing 16% of casein as the sole protein. For the last 3 days they were kept in metabolism cages, and the urine and faeces for each day were collected.They show that data based upon the nitrogen intake and excretion for one day indicate the state of nitrogen balance as well as those based upon figures for 3 days.The results of a study of the nitrogen balance are shown in the table. Ranges, avevages, and standard deviations Values for six rats for three separate days Daily N intake, mg. 203-244, 2373=16*7 232-244, 242 f 4 ' 9 223-244, 241 +8.G Daily N excretion, mg. 121-187, 17Oh 25'4 127-190. I70 5 23.6 I 30-202, 173525.4 N balance yo of ingested (positive), mg. N retained 6 7 5 1 1 . 1 29 f 6.6 54-105. 22-41. 7 ' i 19.3 2 9 5 7 . 2 42-93, 17-42. 57-82, 23-40, 68f18.9 2 9 f 8 . 9 Values for six rats for three days combined 219-244, I 26-190, 54-93, 22-41, 240h10.2Custard apple pulp, when exposed to air, turns pink due to peroxidase activity and becomes bitter when heated above 55", whch renders preservation by heat treatment inapplicable. To preserve the pulp, it is necessary to add 1% of citric acid together with 0 .

in fact Carpenter Sr Olley (personal communication) found that on adding small quantities of formaldehyde to minced herring flesh, in the cold, none could be detected immediately afterwards.The catalytic effect of metal ions, especially iron, on the breakdown of trimethylamine oxide is of interest especially to the canning industry. Considerable quantities of the oxide remain unchanged in the fish after canning and act as a source of oxygen during subsequent storage. This oxygen is of greater importance in the development of oxidative changes during maturation than the gaseous oxygen present in the can headspace. The potential oxygen supply in a 14-oz.can of herring is equivalent to 75-100 ml. oxygen at s.T.P., compared with 3-5 ml. in the headspace gas. In canned herring paste, the residual trimethylamine oxide is reduced within 3 months, but the relative proportions of tri-and di-methylamine formed are not known, a knowledge of which would indicate the amount of oxygen available for reactions in the flesh, and the amount bound up in formaldehyde, which itself may play a part in the development of a matured flavour. The author wishes to thank members of the Scottish and English drifter fleet for co-operating in obtaining samples of frozen herring. Miss Sheila Dick and Miss Rosalie Still carried out most of the trimethylamine oxide estimations and prepared the samples for gas chromatography.Addition of small amounts of EDTA to acidified solutions of ascorbic acid, completely protects the vitamin against copper-catalysed aerobic oxidation for over 6 days at room temperature. In the absence of acid, excess EDTA acts as a pro-oxidant for the vitamin. Under optimal conditions solutions of ascorbic acid containing EDTA could be heated on the water-bath to complete evaporation without any loss of the vitamin.

SUMMARY A purified peroxidase enzyme solution was prepared from custard apple pulp, and its characteristics studied. Its catalytic effect on oxidizing various aromatic amines and phenols was reported. Ascorbic acid oxidase is shown to be absent in the enzyme extract. The influence of temperature, pH, and concentrations of sulphur dioxide, ascorbic acid, sucrose, potassium cyanide, and hydrogen peroxide on the enzyme activity are indicated. The “PZ” value for custard apple pulp was found to be 0.06 on dry basis.

Mango nectar prepared from Banganapalli variety caused less corrosion than nectar prepared from Badami or Raspuri variety. Degree of corrosion was inversely proportional to the viscosity of nectar. Among different fractions of mango pulp, only organic acid fractions were responsible for corrosion. 8-carotene did not contribute to corrosion. Corrosion was more in pulp and nectar prepared from unpeeled mangoes. The peel contains gallic acid and ellagic acid of which the former acts as accelerator of corrosion. Rutin, catechin and pyracatechol acted as accelerators of corrosion but not quercetin. Leucopetunidin and leucopelargonidin have been tentatively identified in the mango peel and they did not affect the process of corrosion.