Am.  Jour.  Pharm. 
Jan.,  1885. 
Analysis  of  Malt  Extract. 
17 
to  be  accomplished,  it  should  be  continued  merely  until  the  color  of  the 
liquid  appears  faintly  yellow.  In  this  manner,  only,  can  the  changes 
of  color  be  distinctly  watched.  Before  adding  the  fluid  to  be  tested, 
5  drops  of  a  10  per  cent,  sulphuric  acid  should  be  added  for  every  2 
oz.  of  water,  in  order  to  arrest  the  further  effects  of  the  diastase,  and  to 
combine  with  the  bases  or  organic  decomposition  products  possibly 
present.  In  this  manner  the  experiment  may  be  made  with  any  kind 
of  water. 
Should  the  changes  of  color  still  be  indistinct,  which,  with  a  malt 
extract  poor  in  diastase,  is  always  the  case,  the  tested  liquid  should  be 
warmed  till  it  appears  colorless.  On  cooling  the  blue  color  appears 
first,  followed  by  the  red,  and  lastly  the  brown  color,  the  latter,  when 
much  albumen  was  contained  in  the  malt  extract. 
Using  a  large  quantity  of  starch  for  these  examinations,  the  warm- 
ing of  the  tested  liquid  is  absolutely  necessary,  as  the  large  amount  of 
dextrin  produced  will  hide  the  color  reactions.  If  we  wish  to  omit 
the  iodine  reaction,  determinations  of  the  sugar,  dextrin  and  gum  must 
be  made,  which  will  be  described  further  on.  In  this  place  it  may  be 
sufficient  to  say,  that  100  parts  of  starch  are  equal  to  105.8  maltose  or 
111*6  grape  sugar. 
Extracts  of  different  diastatic  value  requiring  for  the  transformation 
of  an  equal  weight  of  starch  2  minutes  at  100°F.,  require  for  5  parts 
of  starch  7  minutes  at  150°F. ;  4  minutes  at  100°F.,  require  for  5 
parts  of  starch  10  minutes  at  150°F. ;  5  minutes  at  100°F.,  require  for 
5  parts  of  starch  18  minutes  at  150°F.;  7  minutes  at  100°F.,  require 
for  5  parts  of  starch  27  minutes  at  150°F. 
One  part  of  the  same  malt  extract  requires  the  following  time  for 
dissolving  different  amounts  of  starch  at  100°F.  and  150°F  : 
1  part  starch  2  minutes  at  100°F. ;      h  minute  at  150°F. 
2  parts  "5  "  "  31  minutes  " 
5    "        "    45       "          "             18       "  " 
10    "        "    95       "  "  60 
50    "        "    12  hours        "  120       "  " 
(still  violet.)  (still  violet.) 
One  part  of  another  extract  neutralized  required  at  150°F.,  for  1 
part  of  starch  4  minutes ;  for  2  parts  of  starch  10  minutes;  for  5  parts 
of  starch  60  minutes. 
Ash  Determination. — To  determine  the  several  constituents  it  is  best 
to  use  a  solution  containing  10  grams  of  malt  extract  in  every  lOOcc. 
