Volume 2, Issue 3
September 1935, pages 237-341
pp 237-253 September 1935
Activated carbon (both powdered and granular) is effective in removing the colour, taste and odour from the treated water as supplied to the City. The treatment with the granular carbon resulted in the organic matter being reduced to a greater extent than with powdered carbon.
When used in a slow sand filter (as a sandwiched layer 11/2") for filtering the lake water, granular activated carbon had a distinct sphere of usefulness. It was found that the filter containing the carbon layer yielded a better effluent than the control filter.
When used as a contact medium for the removal of colour, tastes and odours formed in a carefully controlled experimental slow sand filter effluent, activated granular carbon gave very satisfactory results.
The granular carbon used in our experiments since September 1933 has not shown any evidence of deterioration in quality after 23 months of continuous service.
pp 254-279 September 1935
pp 280-315 September 1935
pp 316-321 September 1935
It has been shown that “in vitro” digestions of milk can be dilatometrically followed not only with greater ease and accuracy but also with considerable economy of research material. A strict proportionality between the dilatometric depression and the release of amino nitrogen has been shown to exist for three different concentrations of milk and casein.
The behaviour of the casein particle in cow’s milk towards tryptic digestion does not appear to be different from that of the casein particle in artificial solution. A dilatometric study of the rate of digestion of milks from other sources and of those subjected to various chemical and physical treatments, is now in progress.
pp 322-332 September 1935
Aluminium vessels appear to be well suited for milk and milk products.
Fruit and vegetable juices dissolve only a small amount of aluminium from utensils during storage. The amount of aluminium dissolved is not a function of titratable acidity but possibly depends on the nature of organic acid present and also the buffering capacity of food material.
The corrosive action of acid foods on aluminium is increased by the presence of salt. The amount of aluminium dissolved by tamarind solution containing salt during storage is very nearly equal to the sum total of the amount of aluminium dissolved by acid and salt taken separately, so that each seems to act independent of the presence of the other.
The amount of aluminium dissolved in the ordinary process of cooking is very small, but in cases when acidic foodstuffs containing salt are cooked and stored for fairly long periods in aluminium vessels, the maximum that may be added to the daily diet from utensils will be about 50 mg.
Acidic foodstuffs containing salt after boiling in aluminium vessels should not be left long in the same vessel where corrosion has already started since in many cases, pin pricks may appear at the sides around the points of previous attack.
Feeding experiments with rats have shown that food prepared in aluminium vessels has no harmful effect on growth, reproduction and general well-being of the animals.
pp 333-341 September 1935
A dilatometric study of the hydrolysis of soluble starch with takadiastase has been carried out in the two-bulb dilatometer.
The depression per millimol release of maltose and the depression per degree fall in rotation are found to be 4·0 and 10·7 respectively.
Potato starch and the amylopectins prepared by two distinctly different methods have also been subjected to similar dilatometric studies. The depressions per millimol release of maltose are 4·0, 3·6 and 3·7 respectively. In the case of amylopectic prepared by Ekert and Marzin’s method, the depression per degree fall in rotation is 10·7, a value which agrees very well with that for soluble starch.
It is suggested that the dilatometer offers a convenient method for studying the relative digestibilities of starches from various sources.