Enzyms of Apples 



nase occurs in ripening fruits. It was intended at the outset to ascertain 

 whether a pectinase was present in the apples used in this investigation, 

 but review of the literature dealing with methods of detection of pectinase, 

 as summarized by Cooley (4) in a recent article, together with the unsat- 

 isfactory results of Cooky's own use of these methods in testing for pecti- 

 nase in diseased plums, made it appear doubtful that accurate evidence 

 on this point could be secured. Some preliminary tests of the methods 

 which had been suggested confirmed the writer's opinion in this respect, 

 and the attempts were postponed until such time as more satisfactory 

 methods of testing for pectinases have been devised. 



CNZYMS IN THE SEEDS OF APPLES 



Although the occurrence of different enzyms in the seeds of the apple 

 would not have any bearing upon the ripening processes in the flesh of the 

 apple and, hence, is of no importance to the particular object of this inves- 

 tigation, such an excellent opportunity was offered to test for enzyms in 

 the seeds at the same time that the tests were being applied to the flesh 

 or juice, that it was determined to carry on such a series of tests. Ac- 

 cordingly, a large number of seeds, some 20 gm. in all, were picked out of 

 several apples, and the brown seed coat was picked from each seed. The 

 white seeds were then kept for about two weeks in a vacuum desiccator 

 until they were dry enough so that when crushed they gave off no odor 

 of benzaldehyde, thus indicating that not enough water was present to 

 permit the glucosidase action to occur. 



A weighed quantity of the dry seeds was then ground in a mortar with 

 sharp quartz sand until the seeds were thoroughly disintegrated. The 

 material was then preserved in a tightly stoppered weighing bottle until 

 needed for each test. For the tests, 2 gm. of the mixture, equivalent 

 to I gm. of dry seeds, were digested at room temperature for 30 minutes 

 with 100 c. c. of distilled water, and a filtered aliquot of this extract was 

 used for the tests. A detailed description of the progress of each par- 

 ticular test is unnecessary in this article, but the results obtained, based 

 upon a comparison of unboiled and boiled extracts with water controls, 

 show the following facts with reference to the presence of the various 

 enzyms which were tested for in apple seeds: Diastases, present in con- 

 siderable amount; invertase, absent; emulsin, present in considerable 

 amount; lipase, present in small amount; protease, present (hydrolyzes 

 both albumin and peptone) ; oxidases, absent. 



SUMMARY 



From the results of these investigations it appears that the only enzyms 

 which participate in the changes in the carbohydrates of apples during 

 the ripening process are oxidases. None of the common types of car- 

 bohydrate-splitting enzyms could be found. The fact that the changes 

 which take place during ripening are inhibited by surrounding the fruit 

 in an atmosphere of carbon dioxid, as shown by the experiment described 



