226 MASS. EXPERIMENT STATION BULLETIN 280 



Society in September, 1931, on "A rapid centrifugal method for pectic acid de- 

 termination." This paper has been accepted for publication by Industrial and 

 Engineering Chemistry. The method greatly shortens the usual analytical pro- 

 cedure for pectin determinations in fruit products. 



Effect of Microorganisms on the Jellying Power of Fruit Juices. 



(C. R. Fellers, J. A. Clague, and R. L. France). Data obtained in this cooperative 

 project with the Bacteriology Department show that yeasts do not affect the 

 jellying power of pectinous solutions. Several molds, howeve:", are very active 

 in the decomposition of pectin and render fruit juices containing them incapable 

 of being used for jelly. Bacteria will be next studied in this connection. 



Preservation and Nutrition Studies with Cranberry Products. (C. R. 



Fellers and J. A. Clague). Further laboratory and commercial experience has 

 proved that canned cranberry sauce should have a soluble solids content of 

 approximately 42-13 per cent. At our suggestion commercial canners are now 

 using Abbe refractometers to control the finishing point on canned cranberry 

 sauce. By this means uniform consistency and maximum yields are obtained. 



Dr. H. J. Franklin of the Cranberry Station furnished us with 39 varieties of 

 Massachusetts-grown cranberries last year and 25 varieties of New Jersey and 

 Wisconsin cranberries this year. These varieties are being tested for suitability 

 for manufacture of strained and whole-fruit cranberry sauce. Results to date 

 indicate that only a few varieties are suitable for sauce; the only way some of 

 the poorer varieties can be used at all is by blending. Each variety is also tested 

 for pectin and benzoic acid. Preliminary analyses indicate a great variation 

 among varieties in benzoic acid content; for example, the Early Black has 0.04- 

 0.05 per cent as against 0.09-0.10 per cent in Howes variety. We plan to see if 

 there is any relation between keeping qualities of varieties and benzoic acid 

 content. 



Vitamin studies (C. R. Fellers and P. D. Isham) on cranberries and cranberry 

 products have been continued with the aid of funds made available by the Amer- 

 ican Cranberry Exchange. Cranberries and wild blueberries are moderately 

 rich sources of vitamin C, from 3 to 4 grams daily sufficing to protect 300-gram 

 guinea pigs. Unstrained cranberry sauce retained about 80 per cent of the vita- 

 min C; but the strained sauce, pasteurized juice, and dried cranberries contained 

 scarcely any of this vitamin. Studies are now under way to determine the vita- 

 min A, B, and D potencies of cranberries. The work on blueberries will also be 

 continued. 



Physiological studies on human subjects showed that large doses of cran- 

 berries (100 grams or more) greatly increased urinary aciditj' and markedly 

 lowered the blood alkali reserve. Small daily feedings of 22 grams produced no 

 acidosis but did increase the acidity of the urine. Indirect calculations from the 

 hippuric acid content of the urine following cranberry ingestion lead to the con- 

 clusion that from 0.6-0.85 per cent of quinic acid or a related substance is present 

 in cranberries. This substance acts similarly to benzoic acid in the body and like 

 the latter is eliminated as hippuric acid. 



Methods of extraction of cranberry juice are being studied with the coopera- 

 tion of C. C. Rice. Cranberry juice makes a popular beverage and is especially 

 suitable for blending purposes because of its high flavor, acidity, and color. 



Utilization of Onions by Canning and Drying. (C. R. Fellers). ^The 

 continued examination of experimental packs of canned onions has further 



