SCALDING, PRECOOKING, AND CHILLING 
11 
table, as it merely shows the percentage composition of the spinach 
before and after the scalding and chilling treatments. 
Table 1. — Results of chemical analyses of spinach, before and after treatment. 
[Each result is the average of three samples.] 
Average constituents (per cent) . 
Treatment of material, if any. 
Mois- 
ture. 
Alcohol. 
Sugar, 
as dex- 
trose. 
Poly- 
saccha- 
rides, as 
starch. 
Nitro- 
Solids. 
Solu- 
ble. 
Insolu- 
ble. 
pro- 
tein. 
91.61 
92.31 
92.72 
92.59 
93.11 
8.39 
7.28 
7.41 
6.89 
2.75 
2.08 
1.54 
2.06 
1.65 
5.63 
5.60 
5.73 
5.32 
5.23 
0.18 
.10 
.09 
.09 
.05 
0.76 
.73 
.70 
.71 
.66 
2.39 
2.76 
Scalded 2 minutes, drained 30 seconds, and 
2.77 
Scalded 4 minutes in boiling water 
Scalded 4 minutes, drained 30 seconds, and 
chilled in cold water 
2.58 
2.56 
Extended discussion of the figures appears unnecessary. It is 
seen that spinach has a high moisture content,' is relatively high in 
protein content, and low in carbohydrates. In this case, the per- 
centage of moisture is slightly greater in the scalded than in the 
unscalded spinach, though this may vary, as already pointed out. 
The chemical changes that occur in the chlorophyll have been dis- 
cussed under the. topic of color and appearance. The percentage of 
total protein is not very different in the scalded and the unscalded 
material. 
A detailed study of the changes that occur in the protein was not 
undertaken. Any albumins present would be coagulated, and other 
proteins would probably be altered. Certain sulphur-containing pro- 
teins are altered with more or less elimination of hydrogen sulphid. 
The polysaccharides seem to be a mixture in which the quantity of 
starch is very small. In this case, no blue color developed upon 
the addition of iodin. Starch, if present, would be gelatinized in 
scalding. 
One significant change noted in this study was the effect of scald- 
ing and the subsequent processing upon the pectinlike substances 
which hold the cells together. The middle lamella? swell and often 
dissolve, so that the cells become more or less separated from each 
other or may be separated from each other by the mechanical treat- 
ment received in subsequent handling. This was especially notice- 
able in the fibrous portions of the material. Sodium bicarbonate 
in the scalding water hastens this action and increases the disinte- 
gration of tissues. It is because of this action that soda shortens the 
time necessary to cook spinach .and some other vegetable foods. 
CONCLUSIONS REGARDING THE SCALDING OF SPINACH. 
These studies have indicated that some form of precooking is ad- 
vantageous in the canning of spinach. Driving out the air from the 
tissues reduces the bulk, and facilitates the packing; it likewise 
reduces the internal pressure of cans during processing, which other- 
wise would be excessive. If filled into the cans hot it also lessen- 
