TO PRESERVE EGGS

Rodney and Otamatea Times, Waitemata and Kaipara Gazette, 23 August 1911, Page 7

TO PRESERVE EGGS

Many chemical processes have been devised for the preserving of but only two, the water-glass \nd lime water processes have been generally adopted. No satisfactory explanation of the preservative action of water-glass (sodium silicate) has yet been given. The simplest theory is that the pores of the eggshell are stopped by a precipitate of gelatinous silica, and that the solution of one part of water-glass in 15 parts of water protects the eggs from the air and from bacteria. The collodial solution cannot traverse the membrane which covers the egg. A mixture of water-glass and calcium carbonate hardens in the air, although no chemical reaction, causing the formation of calcium silicate, takes place. R. Berger concludes from his experiments, published recently in the "Zeitschrift feur Chemie und Industrie der Kolloide," that the product which is formed from the waterglass and the calcium carbonate hardens in the air, although no absorption occurs, and stops the pores. Solutions of soap and other colloids were found to exert a similar preservative effect on eggs. The best result was obtained from a mixture of water-glass and a 10 per cent, solution of resin soap containing the smallest possible excess of soda. The temperature of the water-glass was 120 to 125 degrees F.