Agricultural Research in N. H. 17 



Analyses were made after washing and hulling the berries (one sam- 

 pling, thoroughly mixed) ; again after 12 hours of quick freezing, of equal 

 weights of berries packed plain and packed with syrup. In order to know 

 the actual quantities of sugars present in the fresh berries, analyses were con- 

 ducted for total sugars, fructose, glucose, and non-fermentable carbohy- 

 drates. These samplings were made on the fresh berries and after five and 

 eight months storage of the preserved berries. Ascorbic acid determinations 

 were run at the same storage periods. 



The syrup used in the preservation of the berries was also subjected to 

 the ascorbic acid determination in an attempt to obtain a figure comparable 

 to a blank for the ascorbic acid evaluation. 



In an attempt to determine to what extent various sugars react with the 

 dye, pure sugar solutions were run through the routine method for ascorbic 

 acid determination. The amount of reaction with the dye varied with the 

 concentration of sugar. 



Since extraction of ascorbic acid is carried out by means of a strong 

 acid (metaphosphoric), it is obvious that the sugars present in the berries 

 (or the added syrup) might be hydrolyzed. In order to determine whether 

 or not the action of metaphosphoric acid on these sugars is a specific one, 

 sugar solutions prepared in phthalate buffer (no HPO3 used) were reacted 

 with the dye. These gave readings at pH 3.6 which is commonly agreed up- 

 on as the best point for reaction of ascorbic acid with the dye. However, 

 the use of metaphosphoric acid, prior to buffering and reacting with the dye, 

 did give slightly higher values than were obtained with the phthalate buffer 

 aione. This additional action could have been due to more complete hydro- 

 lysis. 



If hydrolysis occurs during preparation of tissue for determination, or 

 during frozen storage, glucose and fructose would be present to a greater ex- 

 tent than sucrose, at the time of the determination. Pure solutions of both 

 glucose and fructose gave higher ascorbic acid values than did sucrose. It 

 became obvious that some quantitative information regarding the distribu- 

 tion of various sugars, at the different storage periods, would be necessary 

 before actual ascorbic acid values, due to berries alone, could be determined. 

 After five months' storage, the sucrose concentration of the berries frozen 

 with syrup was greatly decreased from values for fresh berries, while both 

 glucose and fructose were increased — hydrolysis had occurred. Therefore, 

 the ascorbic acid values obtained, which showed more ascorbic acid in the 

 boxes of stored berries than had ever been placed in the box, were erroneous- 

 1) high because of the specific sugars present which were capable of reacting 

 with the dye, used in the customary manner as evaluation of ascorbic acid 

 c«.>ncentration. Some quantitative relations between the concentration of 

 sugars and "apparent" ascorbic acid values seem to be indicated, but even 

 by applying these corrections it is not possible to account for all the: discre- 

 pancies noted in the ascorbic acid figures for sugared berries. The possibili- 

 ty exists that other naturally occurring substances might be capable of react- 

 ing with the dye. Because it was noted in the literature that tartaric acid seems 

 to exert a protective action on ascorbic acid in preserved strawberries, a se- 

 ries of studies upon the reactions of certain dicarboxylic acids (naturally oc- 

 curring and produced in tissue metabolism) was undertaken. The natural 



