26 MASS. EXPERIMENT STATION BULLETIN 436 



Ascorbic Acid, Carotene, Chlorophyll, Riboflavin, and Water Content of Sum- 

 mer Squashes. (Arthur D. Holmes, Albert F. Spelman, and Carleton P. Jones.) 

 Seven varieties of this vegetable were studied. Five were Cucurbita pepo L. and 

 two were Cucurbita moschata L. The ascorbic acid content of the raw squashes 

 varied from 4.2 mg. for Cocozella to 16.7 mg. per 100 gm. for Early White Bush 

 Scallop. Four varieties — Early Summer Crookneck, Early Summer Prolific 

 Straightneck, Golden Cushaw, and Early White Bush Scallop — contained over 

 half as much ascorbic acid as milk, decidedly over half as much as summer to- 

 matoes, and from 50 to 100 percent more than late-winter tomatoes. The caro- 

 tene content varied from 0.06 mg. for Early White Bush Scallop to 6.21 mg. per 

 100 gm. for Golden Cushaw. Two varieties, Butternut and Golden Cushaw, 

 were extremely rich in carotene. The chlorophyll content varied from 0.42 mg. 

 for Early Summer Prolific Straightneck to 12.25 mg. per 100 gm. for Zucchini 

 Grey. The two squashes with green-colored skins, Cocozella and Zucchini, 

 contained large amounts of chlorophyll. The raw squashes were rich sources of 

 riboflavin. The Earlj^ White Bush Scallop contained about 2>i percent. Butter- 

 nut about 49 percent, Early Summer Crookneck about 79 percent, Cocozella 

 more than 115 percent, and Golden Cushaw about 166 percent as much riboflavin 

 as milk produced in this locality. 



Vitamin Content oj Field-Frozen Kale. (Arthur D. Holmes, Beula V. McKey, 

 Katherine O. Esselen, Leo V. Crowley, and Carleton P. Jones.) It is generally 

 agreed that the leafy green vegetables are extremely valuable components of the 

 human diet. Unfortunately, nearly all the green vegetables are seriously dam- 

 aged, if not destroyed, by freezing temperatures. Following the first killing frost, 

 there is a considerable period during which plants that escape the frost thrive, 

 and kale is one of these. Because of the scarcity of fresh green leafy vegetables 

 in gardens in this area during the late fall, it seemed desirable to determine the 

 vitamin content of field-frozen kale. Dwarf Blue-Green Scotch kale that had 

 been subjected to freezing seven times during the previous month, was collected 

 for assay. Eighteen samples were examined. Very mature and immature leaves 

 were analyzed, with the following results: 



Mg. per 100 gm. 



Very Mature Immature 

 Leaves Leaves 



Ascorbic acid 158.6 212.2 



Carotene 6.3 5.6 



Nicotinic acid 1.94 2.21 



Pantothenic acid— 0.73 0.91 



These figures supply evidence that field-frozen kale can contribute essential 

 nutrients for the human diet, especially when the supply of fresh green leafy 

 vegetables grown in this area is limited. 



Physico-Chemical Properties of Starch. (Monroe E. Freeman.) The ab- 

 normal specific heats found previously for starch suspensions may be explained 

 by the presence of a loosely bound shell of absorbed water on the starch grains. 

 The quantitative data follow mathematical equations relating the composition 

 of the sample, the heat of desorption, the amount of loosely' bound water, and 

 the maximum hydration capacity. The identical behavior of gum arable, lemon 

 pectin, egg albumin, and gelatin verifies this explanation. Cellulose, agar agar, 

 and sodium bentonite systems apparently do not have this loosely bound fraction. 

 This seems to be a general characteristic of hydrophillic colloids that has not been 

 previously demonstrated. 



