Chemistry and physics in relation to hygiene.

  • International Congress of Hygiene and Demography.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry and physics in relation to hygiene. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    rapidly revolving in different directions. The grains are reduced to a state of fine division by their own moiuentuiu, and the result is a fine whole-meal. The advantages of this method are many. In the first place the meal is thoroughly aerated, and, secondly, there is no metallic or stony adulteration ; thirdly, the meal is very free from microbes and other aerial impurities, for the air is filtered before being delivered to the chambers. These two specimens demonstrate the possibility of manufacturing whole-meal bread in which the bran particles are so fine as to entirely obviate any irritating effects. Improvements in non-whole-meal breads. These may be divided into ;— 1. Improvements in white bread. 2. Improvements in brown bread. White bread is certainly deficient in proteid material, fat, and mineral matter. The reason of this is well-known. Fine white flour is obtained chiefly from the centre of the grain, and the bran and the germ are rejected. The bran and the germ are the portions of the grain richest in proteids, fat, and mineral matter, while the central part is poor in proteids and phosphates, and rich in starch. Hence it follows that bread made from fine white flour is also deficient in nitrogenous matter, fat, and inorganic constituents, and is correspondingly rich in starch. Any process, therefore, which secures :— 1. A higher per-centage of proteids ; 2. „ „ fat; 3. „ „ phosphates; may be regarded as an hygienic improvement in the quality of the bread. There appears to be a consensus of opinion that if a larger per- centage of our carbo-hydrate food took the form of soluble bodies (sugar and dextrin) the economy would gain considerably by such a substitution. Any process, then, which secures this, may also be regarded as an hygienic improvement, inasmuch as the bread would be more digestible. The standard ratio of nitrogenous matter to carbo-hydrate material may be taken as 1 is to 3 ‘ 2. The ratio in ordinary fine white bread is as 1 is to 7. Number 3. Black’s Fermented Bread is a white bread which is characterised by a high per-centage of nitrogen. This result is obtained by a special process in which “ strong flours ” are taken and formed into dough, and then treated with lime- water. The gluten is concentrated, and part of the starch precipitated, so that a dough is obtained very rich in proteid material. This dough is then added to ordinary dough, and the result is a mixture with a very high proportion of albuminoid matter. This characteristic is obtained without any deterioration of texture or flavom’, and the ratio of nitrogenous matter to carbo-hydrates is as 1 is to 3 • 6, very near the normal.