86 MASS. EXPERIMENT STATION BULLETIN 198. 



In order to have complete respiration, berries require a constant supply 

 of oxygen during storage. Without this they become asphyxiated and 

 die prematurely. 



Good storage must include control of both ventilation and temperature. 



Methods. 



For the Determination of Chemical Composition. 



In drying the cranberries for the determination of water it was necessary either to puncture 

 the skin of the berry in numerous places with a pin, or to cut it into quarters with a knife. Fifty 

 grams of cranberries were punctured or cut in pieces and spread in a shallow glass dish which 

 was placed in a drying oven at a temperature between 50° and 60° C, where it remained until 

 the fruit was brittle enough to be easily pulverized. The dish and contents were then cooled 

 in the open air and the weight of dried material ascertained, after which it was pulverized and 

 stored in a tightly corked bottle. Weighed charges of the air-dry material were subsequently 

 used for moisture determinations, and the total water content of the cranberries calculated. 



For the determination of sugar and acid, 50 grams of cranberries were mashed, a few at a 

 time, in a porcelain mortar and washed with water into a 500 cubic centimeter volumetric flask 

 by the aid of a wash bottle, short-stemmed funnel and long glass rod. The flask and contents, 

 which amounted to 300 cubic centimeters, were set on a boiling water bath and allowed to stand 

 about one hour. The flask was frequently shaken, and the pulp and water finally made a fairly 

 homogeneous mass through which the sugar and acid were diffused. The liquid was cooled to 

 room temperature and made up to 500 cubic centimeters. The flask was shaken and the contents 

 then poured on a fluted filter large enough to hold the whole. The funnel was covered and a 

 flask used to catch the filtrate so that evaporation would be reduced as much as possible. 

 Aliquots of 100 cubic centimeters were used for sugar determinations, which were limited to the 

 total sugar after inversion. Clarification was accomplished with Home's dry lead subacetate, 

 and the soluble lead in the cleared solution was removed by dry sodium carbonate. 



Total acidity was determined in aliquots of 25 cubic centimeters of the cranberry solution, 

 which were diluted with several volumes of water and titrated with tenth-normal sodium 

 hydrate, using phenolphthalein as the indicator. The pink color of the cranberry solution seemed 

 at first to make the use of an indicator almost impracticable, but the cranberry pigment proved 

 to be a crude indicator itself. As the alkali was added the pigment changed from pink to blue, 

 and subsequently faded to a pale green as more alkali was introduced. The end point was 

 clearly marked by the appearance of a dark purple tint when the turning point of phenol- 

 phthalein was reached. The total acid was calculated as citric acid, though benzoic acid i and 

 malic acid2 have been shown to occur in small quantities in the cranberry. 



The proximate food constituents — ash, protein, fiber, ether extract and nitrogen-free 

 matter — were determined in the dried material by the standard methods. 



Ether extract from the cranberry is a mixture of true fat from the seeds, wax from the skin 

 and more or less of the fruit acids, — citric, malic and benzoic, — all of which are soluble in 

 ether, the last most easily. In some of the samples the ether extract was warmed with the addi- 

 tion of water, and its acidity determined, but as it could be only an approximate correction it 

 was thought best to leave the total ether extract uncorrected for acids present in it. 



1 Mason, Jour. Am. Chem. Soc. 27 (1905), p. 613. 



' Bigelow and Dunbar, Jour. Indus, and Engin. Chem. 9 (1917), p. 762. 



