12 EXPERIMENTS ON PROCESSING PERSIMMONS. 



phere deprived of oxygen the fruit remained firm; accordingly the 

 use of some inert gas in which to keep persimmons while exposed to 

 the vapors of alcohol suggested itself. Experiments in the use of the 

 inert gas most readily available, namely, carbon dioxid, were, therefore, 

 started with the first fruit received in 1910. This gas, while more 

 active chemically than hydrogen or nitrogen, could, it was thought, 

 have but slight effect on the vital processes of the fruit, as it was con- 

 tinually being formed by the fruit itself. Second, the fruit must be 

 kept from cracking by lessening the humidity during processing. 

 These two problems were considered together when practicable. 



PREVENTION OF SOFTENING DURING PROCESSING BY KEEPING IN 



CARBON DIOXID. 



Experiment 1. — Five firm and well-colored fruits of Hachiya were 

 placed in each of two desiccators. In the upper part of each desic- 

 cator, resting on the fruit, was placed a block of paper pulp weighing 

 about 100 grams and wet with 200 cc of an alcoholic solution con- 

 taining 18 per cent by volume. 1 A slow constant current of air 

 was drawn through one of the desiccators, while the other was 

 unaerated. After several days the aerated persimmons were found 

 to be perceptibly softer than those unaerated. 



Experiment 2. — A similar experiment was begun on September 28, 

 using Tane-nashi persimmons which had been received from Florida 

 on September 21 and held in cold storage. Fourteen fruits, all firm 

 and well colored and equally mature, as judged by color, were used. 

 Three were held as checks. These became soft during an interval 

 of five days. Four were inclosed in a desiccator, in which the air 

 was continually renewed, with a pad of paper pulp charged with the 

 18 per cent alcohol. At the end of five days three of these persim- 

 mons were soft and one remained firm. Four fruits were kept in a 

 third desiccator containing a pad of paper pulp wet with the alcohol 

 and in which the air was displaced by carbon dioxid. 2 These fruits 

 were all firm at the end of five days. Three other fruits were kept 

 in a fourth desiccator in which no alcohol was used and in which the 

 air was displaced by carbon dioxid. At the end of five days all of 

 these fruits were firm. 



Experiment 3. — A third set of experiments was begun on October 3, 

 using Hachiya and Tane-nashi persimmons which l\ad been received 



i The alcohol contained 1 part iD 20,000 of mercuric chlorid to prevent possible acetification. It has been 

 suggested that acetic acid might possibly be the active agent in the sake tubs. The results of these experi- 

 ments negative this possibility. 



2 The carbon dioxid used was obtained from a steel cylinder of liquefied carbon-dioxid gas. This is by 

 far the most convenient and economical source of carbon dioxid in the quantities likely to be used in per- 

 simmon processing. It can be had from dealers in soda-water supplies in cylinders holding 20 pounds at 

 about 10 cents per pound. This amounts to a cost of about 1 cent per cubic foot of carbon-dioxid gas 

 at atmospheric pressure. It is necessary to use a reduction valve in releasing the gas from the very bigh 

 pressure at which it is confined in the cylinder, as otherwise it tends to solidify in the stem of the needle 

 valve, and when this occurs the delivery of the gas becomes quite unmanageable. 



