Experimental cookery

The directions in the laboratory outline state to boil the sirup to a temperature of 103°C. for jelly. This is for a location where the water boils at 99°C. This is sufficient for fruit juices that contain a high per- centage of pectin and have a high acidity. This would give approximately 60 per cent of sugar in the finished jelly. Some juices with a low acidity and pectin content will yield better jelly if boiled to a higher temperature than 103°C. A temperature between 104° and 105°C. yields a jelly with a sugar content of about 65 per cent. If they do not jell with a tempera- ture of 105° to 106°C. the juice does not contain sufficient pectin or acid. Jelly test. The method of housekeepers of determining when jelly is boiled sufficiently is to let a portion of the sirup drop from a spoon. When the sirup "sheets" o£E the spoon the jellying temperature has been reached. Storage of Jelly Jelly deteriorates in flavor on standing. Freshly made jelly has a better flavor and aroma than jelly that has been made and stored for some time. The cooking causes some decomposition of flavoring products. In stand- ing, some of the aromatic substances and flavoring substances are volatil- ized and some are probably lost by decomposition. Storage, mold, and sugar concentration. With too high a percent- age of sugar, crystallization of the sugar may occur. With too low a concen- tration, the jelly will mold more readily. It will also ferment more readily than a jelly with a higher concentration of sugar. Singh has reported that jellies made with less than 65 per cent of sugar molded unless the jelly containers were sterilized. 172 JELLY Sterilization of the glasses, and having them dry and hot when the jelly is added, probably aid in preventing mold and also fermentation. Running melted paraffin over the top of the jelly so that it forms a com- plete seal is an aid in keeping it. Definition o£ Jelly This chapter would be incomplete without giving Goldthwaite's defini- tion of an ideal jelly. "Ideal fruit-jelly is a beautifully colored, transparent, palatable product obtained by so treating fruit-juice that the resulting mass will quiver, not flow, when removed from its mold ; a product with texture so tender that it cuts easily with a spoon, and yet so firm that the angles thus produced retain their shape ; a clear product that is neither sirupy, gummy, sticky, nor tough; neither is it brittle and yet it will break, and does this with distinct beautiful cleavage which leaves sparkling character- istic faces. This is that delicious, appetizing substance, a good fruit-jelly." LITERATURE CITED AND REFERENCES Ahmann, C. F., and Hooker, H. D. The Estimation of Pectin and a Study of the Constitution of Pectin. Mo. Agri. Expt. Sta. Research Bull. 77. (1925). Askew, H. O. Changes in the Chemical Composition of Developing Apples. J. of Ponology and Hort. Sci. 8: 232 (1935). Baker, G. L. A New Method for Determining the Jellying Power of Fruit-Juice Extractives. Food Ind. 6: 305 (1934). Campbell, C. H. Jelly. Ind. Eng. Chem. 12: 558. (1920). Also in Am. Food J. 15:24. (1920). Carre, M. H., and Haynes, D. The Estimation of Pectin as Calcium Pectate and the Application of this Method to the Determination of the Soluble Pectin in