18 
BULLETIN 1265, U. S. DEPARTMENT OF AGRICULTURE 
when the peas were canned without any preliminary scalding, 
whereas in cans of peas which were given preliminary scalding the 
strain on cans was much less. At the same time, it was pointed 
out that when scalding was not practiced, the vacuum was also 
unfavorably affected. 
Expulsion of the gases from the tissues is likewise necessary for 
the preparation of an attractive-appearing product, and to make 
possible a satisfactory fill. 
CHEMICAL CHANGES RESULTING FROM SCALDING PEAS. 
Table 2 shows the results of chemical analyses of peas sampled, 
both before and after scalding, for different periods and also after 
chilling for 30 seconds in cold water. No analyses were made of 
the material treated with steam. 
Table 2. — Results of analyses of Early Alaska peas before and after treatment. 
[Each result is the average of three samples.] 
Average constituents (per cent) . 
Treatment of material, if any. 
Mois- 
ture. 
Solids. 
Alcohol. 
Sugars. 
Poly- 
saccha- 
rides, as 
starch. 
Nitro- 
Solu- 
ble. 
Insolu- 
ble. 
Total, 
as 
invert. 
Reduc- 
ing. 
gen, as 
pro- 
tein. 
77.04 | 22.96 
7.99 
6.93 
6.12 
6.42 
5.06 
14.97 
15.60 
13.42 
14.83 
13.25 
3.95 
3.48 
2.98 
3.01 
2.67 





8.27 
8.03 
7.05 
8.00 
7.08 
3.45 
Scalded 2 minutes in boiling water. .. 
Scalded 2 minutes in boiling water 
and chilled 30 seconds in cold water - 
Scalded 4 minutes in boiling water. _. 
Scalded 4 minutes in boiling water 
and chilled 30 seconds in cold water- 
77.47 
80.46 
78.75 
81.69 
22.53 
19.54 
21.25 
18.31 
4.33 
4.46 
5.11 
4.48 
These analyses were of 100-gram samples of the raw and the 
treated peas. The figures show the influence of scalding and chilling 
in cold water on the chemical composition, but the extent of the 
losses is not apparent from these figures. 
Peas are rich in protein and digestible carbohydrates — mainly 
starch and sugar. The sugar seems to be almost entirely cane sugar. 
The differences in the chemical composition observed between the 
fresh green peas and the treated product appear to be due not so 
much to chemical transformations brought about in the brief heating 
as to losses resulting from mechanical injury; to the solvent action 
of the scalding water upon the sugars, mineral matter, and pectic 
substances of the middle lamella?; and to losses resulting from the 
bursting of peas through swelling. 
Scalding yields a product of higher moisture content than the 
fresh peas, and of lower sugar and total polysaccharide content. The 
sugar seems not to be inverted during the scalding treatment, and 
there is no appreciable conversion of the starch to sugar. 
The transformations occurring in the proteins can not be deter- 
mined from the total nitrogen content, but any albumin, if present, 
would have been coagulated. The extent of hydrolysis occurring in 
the protein was not determined and is not known. 
Microclicinical examination of the raw and the scalded peas showed 
that the middle lamellae were softened or partly dissolved during the 
