14 
Analysis  of  Malt  Extract. 
f  Am.  Jour  Pharm. 
1      Jan.,  1885. 
A  malt  extract  prepared  with  sufficient  care  will  always  transform 
the  same  amount  of  starch  in  the  same  time  as  the  malt  which  has 
been  used  for  its  preparation.  For  the  purpose  of  comparison  of 
the  diastatic  effect  of  a  good  malt  extract  we  must  first  determine  the 
diastatic  effect  of  a  good  malt. 
Commercial  malt  varies  greatly  in  quality.  If  we  take  into  con- 
sideration only  well-looking  malt  we  shall  find  that,  although  its 
appearance  allows  the  inference  of  its  being  of  the  best  quality,  it 
nevertheless  varies  greatly  in  its  diastatic  effect.  Malt  is  met  with 
which  Avill  transform  its  own  weight  of  starch  in  2  minutes  at  100°F., 
and  5  times  its  weight  in  7  minutes  at  150°F.,  while  other  malt, 
at  100°F.  Avill  require  7  to  10,  or  even  25  minutes  for  the  conversion 
of  its  own  weight  of  starch,  and  at  150°F.  for  the  transformation  of 
5  times  the  weight  of  starch  will  need  27  to  120  minutes.  Now,  if 
a  malt  extract  be  met  with  which  will  change  its  own  weight  of  starch 
in  2  minutes  at  100°F.,  or  5  times  its  weight  in  7  minutes  at  150°F., 
it  is  to  be  regarded  as  an  excellent  preparation. 
The  manufacturer  cannot  always  secure  malt  effective  in  2  and  7 
minutes,  as  indicated,  and,  therefore,  in  simple  justice,  the  time  should 
be  fixed  at  5  and  18  minutes  respectively;  that  is,  a  malt  extract 
which  will  change  its  own  weight  of  starch  in  5  minutes  at  100°F. 
or  5  times  its  weight  of  starch  in  18  minutes  at  150°F.  should  be 
regarded  as  good.  This  requirement  is  not  too  severe,  and  therefore 
all  extracts  which  do  not  come  up  to  this  standard  should  be  rejected 
as  poor  preparations. 
Examination  of  the  Malt. — For  this  purpose  I  use  1  part  of  malt, 
ground  fine,  to  every  5  parts  of  starch,  which  has  previously  been 
boiled  to  a  paste  with  125  parts  of  water,  and  determine  the  time 
which  is  necessary,  at  a  temperature  of  150°F.,  to  change  the  starch  ; 
that  is,  until  the  liquid  ceases  to  acquire  a  red  color  upon  the  addition 
of  iodine.  A  good  m?lt,  and  a  properly  prepared  malt  extract,  will 
require  for  this  change  from  7  to  18  minutes.  Using  the  malt  as  a 
fine  powder,  or  previously  extracting  it,  will  make  no  difference  in  the 
time  requisite  for  the  transformation. 
A  malt  which  will  transform  5  parts  of  starch  in  7  minutes  at 
150°F.  requires  for  10  parts  of  starch  20  minutes  at  150°F. ;  for  20 
parts  of  starch  70  minutes  at  150°F. ;  for  1  part  of  starch  2  minutes 
at  100°F. 
