8 BULLETIN 1265, U. S. DEPARTMENT OF AGRICULTURE 
cent greater witli sodium-bicarbonate solution than with distilled 
water for the same period ; and during a 4-minute scalding, the losses 
were nearly twice as great with the bicarbonate solution as with the 
distilled water. Although certain volatile substances passed off when 
spinach was scalded with live steam, there was practically no loss of 
nutrient material. When water from the condensed steam drips 
upon the spinach, considerable nutrient matter is dissolved out and 
lost. 
These findings are, in general, in accord with those of other in- 
vestigators. 6 
EFFECT OF SCALDING UPON THE COLOR AND APPEARANCE OF SPINACH. 
Cans of spinach prepared from portions of the spinach used in the 
foregoing experiments, when opened for examination to note the 
effect of the various preliminary treatments upon the color and ap- 
pearance of the canned product, showed the following : 
The spinach canned in tin, without a preliminary scalding, was 
very unattractive. The proportion of liquid to solids was too great, 
and the contents of the can had a foamy appearance due to the libera- 
tion of air from the tissues during the processing. The product from 
the untreated spinach contained in glass jars, however, was quite as 
attractive as the scalded material, but the jars were only about half 
full. 
The canned product prepared from the spinach scalded in water 
was attractive and satisfactory from the standpoint of appearance. 
No perceptible difference could be distinguished between the colors 
of the scalded and the untreated spinach. The different periods of 
scalding, likewise, made no apparent difference in the color of the 
canned product. 
Scalding in 2 per cent of brine had little, if any, effect upon the 
difference in appearance of the product, as compared with that 
scalded in distilled water. The only perceptible difference in the 
spinach scalded in the 0.1 per cent sodium-bicarbonate solution was 
the slightly greater maceration of the tissues previously noted. 
It was thought that the spinach treated with steam showed a 
slightly more natural color than that plunged into boiling water, 
but the difference was very slight. 
In all the lots handled in the various ways outlined, the bright- 
green appearance of the fresh spinach was changed to an olive or 
brownish green color. When fresh spinach is placed in boiling 
water or steam for a short time and then removed, it appears much 
greener. This is due in part to the driving out of air from the 
tissues, or otherwise making the tissues more transparent, so that 
the green is less obscured, and in part to physical changes in the 
condition of the chlorophyll. If the heating is continued for a 
longer time, the material changes to an olive-green or brownish 
green color. 
The losses incurred in the cooking of vegetables in water have been the subject of 
numerous investigations (6, 16, 17, 2!f, 25, 27, 32, 85, 1,0, ! f l, >,8, 1,6, 1,8, 50, 51, 52, 53, 5k). These 
have served to focus attention on similar losses during scalding (which is a partial cook- 
ing), and :i considerable number of papers (5, 25. •>'<;, #8. .',',, .',■'>, {9. 56) have appeared during 
recent years, in which the. matter has received careful scientific study. The effect has 
been to modify the procedure in the treatment of certain vegetables, particularly the leafy 
varieties, by using live steam instead of boiling water, and many of the more recent 
w liters on canning methods recommend exposure to steam in preference to scalding in 
water. 
