SCALDING, PKECOOKING, AND CHILLING 21 
beans are characterized by lack of chlorophyll, the coloring sub- 
stances present being carotinoicls. These results indicate that the 
color of canned string beans is not improved by scalding. 
As with peas and spinach, scalded green beans are bright and at- 
tractive in color when removed from the scalding bath, for the 
same cause explained in connection with spinach. Action of the 
plant acids on the chlorophyll during processing causes chemical 
change of the chlorophyll to phaeophytin, the brownish green com- 
pound previously discussed. 
Chilling the freshly scalded string beans in cold water had no 
effect upon the retention of the color in either the green-podded or the 
yellow-podded varieties so far as could be determined. Repeated 
tests during the four years of study were made on this point, and 
in every case persons invited to select jars of beans which they 
thought had superior color just as often selected unchilled beans 
as those that had been chilled. 
For the reason that turgidity of the fresh beans makes it impossible 
to get a good pack unless they are made flexible by scalding, those 
cans and jars of beans which were not scalded were slack filled, 
and, in this respect, less attractive than those that had been scalded. 
EFFECT OF SCALDING ON THE TASTE AND FLAVOR OF STRING BEANS. 
Examination of the canned product from both the scalded and 
the untreated beans showed but little difference in flavor. This was 
especially true of the beans packed in glass, the partial seal allowing 
the objectionable volatile substances to escape with the steam. Even 
in tin the differences were small. 
Beans scalded in water and those scalded in live steam were equally 
good in flavor. 
Chilling in water after scalding had little, if any, effect on the 
quality of the canned beans. 
MUCILAGINOUS SUBSTANCES AND CLARITY OF LIQUOR IN CANNING STRING 
BEANS. 
No mucilaginous or sticky substances were found on the beans, 
and the clarity of liquor was satisfactory in all cases, therefore 
scalding in connection with both of these matters seems unnecessary. 
RELATION OF SCALDING STRING BEANS TO PRESSURE AND VACUUM. 
In a bulletin by the writers ( 38) , previously referred to, attention 
was called to the internal pressures developed in cans when the beans 
were not scalded. It is essential that the air be expelled from the 
fresh tissues, not only to get a better pack, but also to reduce the 
strain on cans during processing, and to attain a higher vacuum. 
What has just been said relative to internal pressure applies to can- 
ning in tin. In packing in glass, this factor is not important be- 
cause the gases are allowed to escape before the jars are sealed. 
CHEMICAL CHANGES RESULTING FROM SCALDING STRING BEANS. 
In Table 3 are shown the results of careful chemical analyses 
of fresh green beans and of beans given both steam and boiling- 
water treatment. The effect of chilling in cold water after scalding 
is shown also. 
