Carbohydrate Content of Tomato Fruit

Abstract

The carbohydrate content of mature tomato fruit has received considerable attention since ATWATER and BRYANT (1) indicated the total sugar content to be about 3.39 per cent. and the starch less than 0.1 per cent. on the fresh basis. In a later publication of the same series containing revised data, CHATFIELD and ADAMS (6) gave the average reducing sugar content as 3.37 per cent. MYERS and CROLL (11) PLANT PHYSIOLOGY the remaining quarters were cut through the equatorial diameter and the required portions then carefully secured. The samples were then ground in a food chopper and analyzed at once or were placed in cold storage (00 C.) if the analysis could not be completed immediately.Reducing sugars were determined by the SHAFFER-HARTMAN method (15) after clarifying with saturated neutral lead acetate and deleading with sodium oxalate. Dextrose was determined by the method of LOTHROP and HOLMES (10). Sucrose was inverted with invertase for one hour at 550 C. The total reducing sugars present then were determined and the sucrose content calculated by difference. Starch was determined by the following modification of OLMSTEE's method (12). To a 25-cc. aliquot of the sample 0.1 gram of Taka-diastase was added. After careful mixing, the solution was brought to 550 C. and held at this temperature for one hour. After cooling and clarifying, the reducing sugars were determined as previously described. The acid-hydrolyzable carbohydrate material was determined by direct acid hydrolysis (16). This fraction includes the starch. Proper blanks were made for all determinations.Total solids were calculated from the refractive index-total solids ratio determined by CRUESS and ISAYWELL (7)

Proximate, Mineral and Vitamin Analysis of Fresh and Canned Tomato

“…This might be as a result of high water content of the fresh tomato. The result of this finding show a higher carbohydrate content of fresh tomato than that reported by Saywell and Robertson 15 . However it is lower than that reported by Romain and Harry 14,13 .…”

Comparative Clarification of Sugar Solutions

“…Although the hiding powers reported have been determined at one-coat thickness by the new incomplete hiding method described, the method has also been employed for comparing paints at two or more coats and up to complete hiding over this background. It is easy to distinguish small differences in hiding power at contrasts between 1 and 2 per cent and even to make gradings at contrasts below 1 per cent and thus THE recent use of the iodine reduction method in the analysis of honey (8) and in plant materials (10,12) raises the question of the effect of various clarification and clearing methods on the determination. The use of the iodine method for dextrose broadens the problem of clearing solutions for sugar analysis.…”