Experimental cookery

Spencer, G. The Formation of Pectin Jellies by Sugar. J. Physical Chem. 33: 1987 (1929). Spencer, G. The Effect of Salt on Sugar-Pectin Jelly-Formation. J. Physical Chem. 33: 2012 (1929). Spencer, G. The Relation between Acids and Pectin in Jelly Formation. J. Physical Chem. 34: 410 (1930). Spencer, G. The Purification and Estimation of Pectin. J. Physical Chem. 34: 429 (1930). Spencer, G. The Manipulation of Jelly Strength-Testing Apparatus. J. Physical Chem. 34: 654 (1930). Sucharipa, R. Experimental Data on Pectin-Sugar-Acid Gels. J. Assoc. Of- ficial Agri. Chem. 7: 57 (1923). Tarr, L. W. Fruit Jellies. The Role of Acids. Univ. of Del. Agri. Expt. Sta., Bull. 134, Technical Bull. No. 2. (1923). Tarr, L. W., and Baker, G. L. Fruit Jellies. II. The Role of Sugar. Univ. Del. Agri. Expt. Sta., Bull. 136, Technical Bull. No. 3 (1926). Tarr, L. W. Fruit Jellies. III. Jelly Strength Measurements. Univ. of Del. Agri. Expt. Sta., Bull. 142, Technical Bull. No. 5 (1926). Tarr, L. W. Fruit Jellies. Chapter 26, Colloidal Behavior. Edited by Bogue, McGraw-Hill Co. (1924). Tarr, L. W. Fundamentals of Fruit Jelly Formation. Canning Age 5: 684 (1924). 174 JELLY Tolman, L. M., Munson, L. S., and Bigelow, W, D. The Composition of Jellies and Jams. J. Am. Chem. Soc. 23: 347 (1901). Wilson, C. P. The Manufacture of Pectin. Ind. Eng. Chem. 17: 1065 (1925). JELLY Directions for preparing fruit for jelly. Apples and crab-apples are washed but not pared. Remove bad spots and wormy places but retain the seeds and core, as they contain pectic substances. Cut in rather small pieces in order to more easily extract the pectin. Gooseberries and cur- rants are washed but do not need to be stemmed. Add sufficient water to cover apples and crab-apples. Green gooseberries can be covered with water; ripe ones should be only partially covered. For most berries about ^ cup of water to a pint of berries is sufficient, or else the pectin of the juice will not be sufficiently concentrated. Cranberries may be used. Rather ripe cranberries should have a smaller proportion of water than less ripe ones. Drain the juice through a heavy cloth bag. Save the pulp for a second extraction. Water-packed canned gooseberries are excellent to use, as they are easily obtained at any time of the year. The number ten size is more economical. In using the canned gooseberries the juice is not cooked for the first extraction but drained without heating. Experiment 23. A. To determine the pectin content of fruit juice. To 45 or 60 cc. of alcohol in a graduate add 15 cc. of the juice to be tested. Invert the graduate slowly and turn back. A precipitate in a mass indicates enough pectin for jelly. Pour out in a dish and lift the pectin. (See p. 157.) If a quantitative test is desired, follow some standard directions for pectin determinations. B. Test the juice with a jelmeter. Add sugar and cook according to direc- tions furnished wnth the jelmeter. Compare the jellies with those made from the same juice under Experiment 24. Experiment 24. To determine the effect of varying the proportion of sugar to juice in making jelly.