PRODUCTION OF ALCOHOL AND ACETALDEHYDE BY TOMATOES

Abstract

ditions seed plants produce small quantities of alcohol. Lechartier and Bellamy (10) were the first to show that fruits, when deprived of air, produce alcohol as well as CO2. These workers studied a number of varieties of fruits and always found some alcohol produced. They inclosed their fruits in tight containers for several months and in many cases the fruits were considerably disintegrated although they were sterile. From his extensive studies on the maturing of fleshy fruits, Gerber (3) came to the conclusion that in many fruits alcohol is formed during the process of ripening, together with volatile acids and esters. Muller-Thurgau and Osterwalder (13) found alcohol in pears. Thomas (18) found alcohol in apples. Although Gerber studied apples he does not mention having found alcohol in these fruits. Onslow and Barker (17) found alcohol in oranges. The concentration was particularly high when the fruits had been stored in an atmosphere high in CO2, but even in ordinary air alcohol was present to the extent of about 0.03 to 0.10 per cent. It is thus evident that alcohol is produced in fruits when they are surrounded by air. Under anaerobic conditions alcohol has been found in many plant structures, and reference to much literature on the subject is to be found in the monographs (8) on plant respiration. It has been shown by a number of investigators that acetaldehyde is formed in plants. Maze (11) found acetaldehyde in unripe seeds of corn and pear. This acetaldehyde he believed prevented them from germinating. In 1912 Kostytschew (7) demonstrated that acetaldehyde was produced in the alcoholic fermentation of yeast. His method of demonstrating acetaldehyde consisted in adding zinc chloride to the fermenting liquid, which brought about polymerization of the acetaldehyde, preventing it from being reduced to alcohol. Kostytschew et al. (9) found acetaldehyde in poplar blossoms. Acetaldehyde has also been found in other plants: by Muller-Thurgau and Osterwalder (13) in pears and apples; by Neuberg and Eeinfurth (14) in alcoholic fermentation; by Neuberg and Gottschalk (15) in crushed peas and bananas; by Thomas (18) in apples; by Bodnar and co workers (1) in whole seeds of peas; by Klein and Pirschle (6) in flowers, leaves, seedlings, and seeds of a number of different species of plants ; by Harley and Fisher (5) in ripe pears.