Process for spray drying enzymes

This invention involves a process for the preparation of spray dried enzymes.

BACKGROUND OF THE INVENTION 
The concept of using spray drying for preparing dry enzyme compositions is 
known in the art. A protease unhairing enzyme in the form of a whole crude 
culture of bacteria (Pseudomonas effusa) has been successfully spray 
dried. A crude culture of Bacillus subtilis to which wood flour was added 
has also been spray dried. The stability of the activity was poor in the 
latter case and together with the lack of any cost advantage made spray 
drying over tray drying impractical. A protease (Bacillus spp.) was spray 
dried using ultrafilter concentrates but odor, high bacteria count, and 
hazards related to inhalation of alkaline protease dust made this method 
of manufacture impractical. 
Subsequently attempts were made to develop a process for spray drying 
enzyme concentrates (primarily from surface culture) obtained by 
ultrafilter concentration of several culture filtrates. These trials 
indicated that spray drying of enzymes was possible but activity yields 
and solids recovery were frequently low, a large amount of product 
collected on the chamber walls, moisture in the final product was very 
high, caking and darkening of the dried concentrate was frequently 
observed and activity retention was poor during storage at room 
temperature. 
Freeze drying has also been utilized to obtain a dry enzyme composition. 
Initially, freeze drying gave better yields than spray drying. Several of 
the concentrates still gave problems with freeze drying until it was noted 
that supplementation of the enzyme concentrates with selected combinations 
of inorganic salts and insoluble ingredients gave improved results. These 
findings became the basis of U.S. application Ser. No. 939,745 filed Sept. 
9, 1978 by Clifford E. Neubeck assigned to a common assignee U.S. Pat. No. 
4,180,917, issued Jan. 1, 1980. 
In initial studies, several different formulations of enzyme concentrates 
were tested in an attempt to select the type and composition of additives 
to be used in spray drying. These experiments, involved in vacuo drying of 
bacterial alpha-amylase concentrate to which various salts and insoluble 
ingredients were added, demonstrated the critical nature of the additives. 
The variation of the additives had a significant effect on the physical 
nature, activity recovery, moisture level, lumping, color, etc., of the 
product. As a result of the above experimentation, initial spray drying 
experiments were conducted. 
SUMMARY OF THE INVENTION 
This invention relates to a process for spray drying enzymes which 
comprises concentrating a liquid enzyme solution by ultrafiltration, 
adding to said concentrate water-insoluble salts, optionally in the 
presence of water-insoluble suspenders and thickeners, intimately mixing 
the concentrate composition, and spray-drying said concentrate composition 
at air inlet temperatures of from about 120.degree. C. to about 
180.degree. C., and air outlet temperatures from about 68.degree. C. to 
about 85.degree. C. 
In accordance with the process of this invention any conventional 
ultrafiltration equipment can be utilized as long as it fills the 
requirements of being able to not only concentrate the liquid enzyme 
solution but also remove low molecular weight sugars, amino acids, and 
peptides which are the major cause of discoloration, hygroscopicity, odor, 
gumming, caking and other similar factors which lead to deterioration of 
the product and in some cases to unmarketable products. 
Water insoluble salts that can be utilized in the process of this invention 
include tribasic calcium phosphate, tribasic magnesium phosphate, calcium 
carbonate, calcium hypophosphate, calcium magnesium silicate, calcium 
silicate, calcium sulfite, calcium tartarate, magnesium oxide and 
magnesium silicate and the like. Any water soluble salts which when 
combined form water insoluble salts can also be utilized. By water soluble 
salt it is meant any salt which is at least slightly soluble in the media 
in which it is to be dissolved. 
Water insoluble suspenders and thickeners which may optionally be employed 
in the process of this invention include cornstarch, potatoe starch, 
tapioca, cellulose and the like. 
In accordance with the process of this invention the air inlet temperatures 
which can be utilized for the addition of the liquid enzymes concentrate 
composition are from about 120.degree. C. to about 180.degree. C. However, 
a preferred temperature range for the air inlet temperature is from about 
150.degree. C. to about 177.degree. C. more preferably from about 
155.degree. C. to about 165.degree. C. The air outlet temperatures which 
can be utilized in the process of this invention for the spray dried 
enzyme compositions obtained by this process are from about 65.degree. C. 
to about 90.degree. C. However, a preferred temperature range for the air 
outlet temperature is from about 70.degree. C. to about 85.degree. C. more 
preferably from about 75.degree. C. to about 83.degree. C. 
A preferred process of this invention relates to the preparation of a spray 
dried enzyme composition which comprises concentrating a liquid enzyme 
solution obtained from a submerged culture of an enzyme selected from 
Bacillus sps protease, Aspergillus sps protease or Bacillus sps amylase, 
by ultrafiltration, forming water insoluble salts in situ by the reaction 
of a water soluble phosphate salt and a water soluble calcium salt, 
intimately mixing the concentrate composition and spray drying the 
concentrate composition at air inlet temperatures from about 155.degree. 
C. to about 175.degree. C. and air outlet temperatures from about 
75.degree. C. to about 83.degree. C. 
DETAILED DESCRIPTION OF THE INVENTION 
Table I gives a summary of eleven test runs made in small scale using an 
Aspergillus oryzae protease without any additives to illustrate the type 
of result obtained. Similar data were also obtained on other Aspergillus 
oryzae proteases. 
TABLE 1 
__________________________________________________________________________ 
Summary of Preliminary Spray Drying Study using Aspergillus oryzae 
protease 
Concentrates Without Additives.sup.1 
Test Number 
1 2 3 4 5 6 7 8 9 10 11 
__________________________________________________________________________ 
Starting Material 
Activity(HU).sup.2 
17100 
17100 
16400 
16400 
17100 
17100 
17100 
36000 
36000 
47000 
47000 
% Solids 12.5 
12.5 
12.5 
12.5 
12.0 
12.0 
12.0 
16.0 
16.0 
17.2 
17.2 
Drying Conditions 
Air T in .degree.C. 
160 160 130 120 149 149 121 120 130 120 130 
Air T out .degree.C. 
75 75 70 70 71 82 68 70 70 70 70 
Product 
activity HU.sup..sup.2 
73000 
113000 
122000 
125000 
117000 
108000 
137000 
184000 
193100 
216000 
206000 
% Moisture 13.5 
14.1 
10.1 
11.3 
11.3 
11.5 
12.3 
9.4 
9.4 
9.4 10.1 
% Weight 
Recovered.sup.3 
16.4 
29.8 
49.2 
62.8 
41.6 
51.0 
57.2 
77.1 
78.2 
70.7 
66.1 
% Activity 
Recovered 8.8 
27.3 
45.5 
60.7 
38.5 
40.0 
57.6 
65.0 
72.5 
54.9 
51.0 
__________________________________________________________________________ 
.sup.1 Most of these spray dried products were gummy, dark in color and 
hygroscopic. 
.sup.2 An enzyme has an activity of 1000 HU per g. if 11.18 mg. of it 
produces an increase in soluble nitrogen of 5.0 mg. from 0.417 g. 
hemoglobin in 5 hours at 40.degree. C. and pH 4.7. 
##STR1## 
Spray Drying Studies With Additives 
The relatively poor experience with spray drying as summarized in Table I 
(for Aspergillus oryzae protease) led to the testing of a number of 
additives as supplements to the enzyme concentrate utilizing in vacuo 
drying in order to determine the effect on the physical properties of the 
final product. This experimentation was done on Bacterial alpha-amylase 
Concentrate since it was the material considered for initial testing with 
various additives. 
Table II summarizes these results. Surprisingly the best mixture of 
additives from the standpoint of physical appearance (#17) did not give an 
exceptional yield of activity. The formation of calcium phosphate in the 
concentrate by mixing ammonium phosphate and lime gave distinctly better 
properties than adding calcium phosphate alone (#18) with starch (#14 and 
#190) or with ammonium phosphate, lime, and starch (#15). Starch alone was 
not effective. The results suggested that the manner of adding substances 
and the composition had a profound effect on the physical nature of the 
product. 
Spray drying tests were made on Bacterial alpha-amylase concentrate using 
the concentrate alone, concentrate plus cornstarch (5%) and tricalcium 
phosphate (7%) added sequentially and finally a third mixture containing 
concentrate plus cornstarch (5%) and a dry mixture of ammonium phosphate 
(7%) and lime (3.6%). The dry mixture of ammonium phosphate and lime was 
added to the concentrate after the starch has been thoroughly suspended. 
In Table II, aliquots of the enzyme Concentrate at 16% solids and 41000 FM 
Activity were mixed with various additives and then dried in vacuo at 
45.degree. C. The dried material was examined for texture, color, and 
activity in cases where the physical nature of the dried material was 
good. An enzyme with 1,000 starch liquifying units (FM) per g. reduced the 
viscosity of 300 times its weight of potato starch by 90% in 10 minutes at 
70.degree. C. and pH 6.7. 
TABLE II 
__________________________________________________________________________ 
Laboratory Drying Experiments on Bacterial alpha-amylase Concentrate 
Materials Added to Concentrate 
Appearance of Dried Product 
Test % % % % Activity 
Number 
NH.sub.4 H.sub.2 PO.sub.4 
CaO 
Ca.sub.3 (PO.sub.4).sub.2 
Starch 
Color 
Stickiness 
Grinding 
Activity 
Recovery 
__________________________________________________________________________ 
12 -- -- -- -- Dark 
Gummy Very 
Difficult 
Very 
13 -- -- -- 10 Dark 
Gummy Difficult 
14 -- -- 14 10 Light 
None Hard 102000 
91.3 
15 5.2 3.6 
7.0 10 Dark 
Slightly 
Difficult 
Gummy 
16 2.6 1.8 
10.8 10 Light 
None Hard 69600 
108 
17 10.4 7.2 
-- 10 Very 
None Soft 37500 
65 
Light 
18 -- -- 14.0 -- Light 
Sl. Gummy 
Hard 
19 -- -- 10.0 14 Dark 
None Hard 
__________________________________________________________________________ 
Table III summarizes the results obtained when the various mixtures 
disclosed therein were spray dried. 
Bacterial alpha-amylase Ultrafilter Concentrate at 25050 FM (diastase 
activity) and 8.0% soluble solids was divided into 3 parts: 
Mix 1. No additives 
Mix 2. Plus 5% cornstarch and 7% tricalcium phosphate 
Mix 3. Plus 5% cornstarch, 7% NH.sub.4 H.sub.2 PO.sub.4 and 3.6% CaO. 
(Ammonium phosphate and lime mixed dry before addition to the concentrate 
containing starch) 
Each of the compositions was then spray dried at 16,600-18,700 RPM wheel 
speed for atomization and air temperatures of 310.degree. F. (154.degree. 
C.) inlet and 175.degree. F. (80.degree. C.) outlet. Mix 1 was also dried 
at other combinations of wheel speed and temperature. 
As noted in Table III, spray dried product prepared from Mix 1 (i.e. no 
additives) gave poor solids recovery and caking of the product was 
observed after storage for several days. Change in atomizer speed or 
drying temperatures did not alter the results significantly for Mix 1. 
Best recovery of activity and best appearance was obtained with Mix 3 but 
Mix 2 was more readily handled in the pumping system to the atomizer. Mix 
3 gave a lower specific activity. 
TABLE III 
__________________________________________________________________________ 
Spray Dry Test Runs With Bacterial alpha-amylase Concentrate 
Wheel Dry Product 
Composition 
Speed 
Air Temp. .degree.F. 
Activity 
Recovery 
Dried RPM In Out Quality (FM).sup.1) 
Solids 
Activity 
__________________________________________________________________________ 
Mix 1 12,000 
310 173 Poor Drying Poor recovery 
Mix 1 13,300 
310 175 Still Wet 
287,000 
42.3 40.8 
Mix 1 16,600 
310 175 Some 303,500 
62 60.3 
Caking.sup.2) 
Mix 1 16,600 
330 177 Some 292,500 
62 58.1 
Caking.sup.2) 
Mix 1 16,600 
340 179 Some 294,000 
62 58.4 
Caking .sup.2) 
Mix 1 16,600 
350 180 Some 291,000 
62 57.8 
Caking.sup.2) 
Mix 2 18,700 
310 175 Smooth 130,000 
87 80 
flowing 
Light Color 
Mix 3.sup.3) 
18,700 
310 180 Very good 
102,000 
100 100 
Light color 
__________________________________________________________________________ 
.sup.1) An enzyme with 1,000 starch liquifying units per g. reduces the 
viscosity of 300 times its weight of potato starch by 90% in 10 minutes a 
70.degree. C. and pH 6.7. 
.sup.2) Samples prepared from Mix 1 caked into a lump of material with 
dark color after storage. 
.sup.3) Mix 3 had a tendency to clog the nozzles of wheel atomizer. 
Large scale runs were made with Bacterial alpha-amylase Concentrate in two 
different size driers. Basically the additive composition of Mix 2 (Table 
III) was used but slightly different ratios of starch to calcium phosphate 
were employed and the ultrafiltration concentration was slightly more 
efficient in the larger run so that a larger amount of low molecular 
weight soluble solids were removed. Example 1 gives the details of the 
smaller run while Example 2 gives the details of the larger run.

EXAMPLE 1 
Bacterial alpha-amylase Concentrate Spray Dried (Dryer has a water 
evaporation rate of 343 lbs./hour operating at 420.degree. F./200.degree. 
F. inlet/outlet temperature 
A strain of Bacillus subtilis selected to produce alpha amylase was grown 
on 24,000 pounds of medium containing cornstarch, corn steep water and 
inorganic salts using deep tank conditions to produce a culture with 21% 
dry solids and having 19,500 starch liquefying units (FM) per gram.sup.1. 
After filtration and washing on a rotary vacuum filter, 30,800 pounds of 
filtrate were obtained having 12,800 FM units per g and a solids content 
of 13.1%. Activity recovery was 85% with a reduction in solids from 5,000 
lbs. to 4,035 lbs. The culture filtrate was concentrated by 
ultrafiltration to an activity of 45,900 FM/g in a weight of 7,055 pounds 
at a solids content of 19.0%. Solids (primarily in the form of low 
molecular weight solubles) were reduced from 4,035 lbs. to 1,340 
lbs.--about 27% of the solids in the original crude culture or 33% of that 
in the filtrate before concentration. Only 18% enzyme activity was lost. 
FNT .sup.1 An enzyme with 1,000 starch liquefying units per g reduces the 
vicosity of 300.times. its weight of potato starch by 90% in 10 minutes at 
70.degree. C. and pH 6.7. 
Insoluble solids in the form of 400 pounds of cornstarch (5%) and 525 
pounds of tricalcium phosphate (7%) were added to the concentrate to give 
a total weight of 8080 pounds at an activity of 39,900 FM/g. The 
concentrate plus additives was spray dried using a 160 mm wheel for 
atomization rotating at 18,700 RPM. Inlet temperature was set at 
310.degree. F. and the outlet temperature was set at 170.degree. F. 
Product in the amount of 1889 pounds at an activity of 146,000 FM/g was 
collected plus 40 pounds of drying chamber dustings at 146,000 FM/g. 
Solids recovery was 94.6% in the product plus 2.0% in the dustings. 
Activity recovery was 85.3% in the product plus 1.8% in the dustings. The 
moisture content in the light colored free-flowing product was 5.26%. The 
dry concentrate has retained full activity and good flow character after 
storage for several months at room temperature. 
EXAMPLE 2 
Bacterial alpha-amylase concentrate Spray Dried (Dryer has a water 
evaporation rate of 1,400 lbs. per hour operating at 420.degree. 
F./200.degree. F. inlet/outlet temperatures) 
A strain of Bacillus subtilis selected to produce alpha amylase was grown 
under deep tank conditions on 31,400 pounds of medium containing 
cornstarch, corn steep water and inorganic salts to produce a culture 
containing 21% total solids and 16,500 FM per g. After filtration and 
washing, 40,900 pounds of filtrate at an activity of 10,360 FM/g. and a 
solids content of 13% were obtained. Activity recovery was 82% while 
solids were reduced from 6,594 pounds to 5,317 pounds. The culture 
filtrate was concentrated by ultrafiltration at 10.degree. C. to a final 
weight of 8,600 pounds having a solids content of 15.4% and 43,300 FM. 
Solids, primarily in the form of highly colored, gummy, low molecular 
weight material were reduced from 5,317 pounds to 1,315 pounds. The 
discarded soluble solids of 4,002 pounds reduced the soluble solids in the 
concentrate by 75% with a loss in activity of only 12%. 
Insoluble solids in the form of 450 pounds of cornstarch (5.6%) and 300 
pounds of tricalcium phosphate (4.0%) were added to the concentrate to 
give 9,350 pounds of concentrate plus additives at 38,000 FM/g. The 9,350 
pounds of mixture were spray dried using a 260 mm radial wheel rotating at 
11,000 RPM for atomization. Inlet temperature was set at 315.degree. F. 
and outlet temperature was 155.degree. F. Product in the amount of 1,975 
pounds at an activity of 170,000 FM/g was recovered. The activity recovery 
was 94.5% and the solids recovery was 99.6%. The light colored free 
flowing powder contained 4.0% moisture and remained free flowing when 
stored at room temperature for several months. 
EXAMPLE 3 
Neutral Fungal Protease Concentrate 
This enzyme is prepared by growing a selected strain of Aspergillus 
flavus-oryzae on a medium containing a mixture of liver and soybean meals 
and ammonium phosphate under deep tank conditions to produce a fungal 
protease which can be used for protein modification, e.g. meat 
tenderization. Fungal mycelium and medium debris are removed from the 
crude culture by filtration on a rotary vacuum filter using diatomaceous 
earth as a filter aid. Proteolytic activity is measured as casein 
solubilization units (EE).sup.1. The filtered cell free solution 
containing enzyme is concentrated by ultrafiltration and spray dried to 
give a dry stable free flowing solid of high activity as described below. 
FNT .sup.1 Casein solubilization units (EE) are defined as follows: An enzyme 
with an activity of 1000 EE solubilizes nine times its weight of casein in 
1 hour at 40.degree. C. and pH 8.0. 
The crude enzyme concentrate, 15,000 lbs., containing a total dry solids of 
12.8% and 1,590 EE was filtered and washed on a rotary vacuum filter to 
give 18,480 lbs. of filtrate plus wash at 1,300 EE. Filtrate plus wash in 
the amount of 3,450 lbs. (equivalent to 2,800 lbs. of culture and 358 lbs. 
solids) was then concentrated to 440 lbs. at 9,250 EE and containing 12.3% 
solids in an ultrafiltration unit operating at 10.degree. C..+-.1.degree. 
C. The total solids were reduced to 54 lbs. or 15% of the starting culture 
solids. The concentrate at 9,250 EE which contained about 90% of the 
activity present in 2,800 lbs. of culture was divided into two parts of 
120 lbs. and 320 lbs. The second part was supplemented with 21 pounds of 
cornstarch and 24 pounds of calcium acetate added in sequence. Good mixing 
was employed to permit formation of finely divided water insoluble calcium 
phosphate intimately mixed with the starch. A total of 365 lbs. of 
supplemented concentrate was obtained. Activity recovery in the 
supplemented concentrate was 87.5% of that expected. The unsupplemented 
part 1 (120 lbs.) and supplemented part 2 (365 lbs. after addition) were 
then spray dried in the same drier separately using the same drying 
conditions: viz. 310.degree. F./175.degree. F. inlet and outlet air 
temperatures and atomized at 18,700 RPM with 160 mm wheel. Table IV gives 
the results obtained in this experiment. 
TABLE IV 
______________________________________ 
Spray Dried Neutral Fungal Protease 
Concentrate without 
Concentrate with 
Supplementation 
Supplementation 
______________________________________ 
Dry Solids 12.3% 23.0% 
Activity before 
spray drying 
9,250 EE 7,100 EE 
Pounds Concentrate 
dried 119 365 
Pounds of spray 
dry material 
produced 
Collected from 
Cyclone 9.5 79 
Chamber sweepings 
2.5 4 
Activity 72,500 EE 28,500 EE 
Recovery of solids 
82% 99% 
Recovery of 
Activity 79% 91% 
Moisture in 
Product 6.54% 6.79% 
Product Physical 
Dark Color Light in Color 
Appearance Forms lumps on Free flowing 
storage character retained 
on storage 
______________________________________ 
EXAMPLE 4 
Fungal Acid Protease Concentrate 
This enzyme is produced by growth of a selected strain of Aspergillus 
oryzae under deep tank conditions on a medium containing a mixture of 
liver, soybean, and blood meals. The fungus produces a protease active on 
hemoglobin at pH 4.7 and other proteins which may be measured by its 
action on hemoglobin at pH 4.7 in terms of HU activity.sup.1. The protease 
is well suited for the modification of gluten in bakery operations. 
For example, 106,000 lbs. of crude culture at 5850 HU and 12.6% total 
solids were filtered and water washed on a rotary vacuum filter to remove 
fungal mycelium and culture debris. Diatomaceous earth was used as a 
filter aid. The clear filtrate plus wash at 129,850 lbs. had an activity 
of 4,774 HU. 
FNT .sup.1 An enzyme has an activity of 1,000 HU per g if 11.18 mg of it 
produces an increase in soluble nitrogen of 5.0 mg from 0.417 g hemoglobin 
in 5 hours at 40.degree. l C. and pH 4.7. 
The culture filtrate plus wash was concentrated to 9,765 lbs. with an 
activity of 67,000 HU and a solids content of 18.1%. Activity recovery in 
the concentrate was about 90% of that in the crude culture but the total 
solids in the concentrate were reduced to 13.2% of that originally present 
in the culture. 
The 9,756 lbs. of concentrate was supplemented with 60 lbs. of cornstarch 
and 60 lbs. of tricalcium phosphate added sequentially to give 9,885 lbs. 
of supplemented concentrate at 68290 HU and 20.94% solids. The mixture was 
spray dried at 330.degree. F./175.degree. F. inlet/outlet temperature with 
a radial atomizer of 260 mm rotating at 11,000 RPM to give 1,765 lbs. of 
free flowing light tan powder at 314,600 HU. The moisture level in the 
final product was 3.67%. Activity and solids recovery were 82% and 85% 
respectively. 
Another lot of this enzyme Concentrate prepared from a different batch but 
processed in the same way was spray dried under the same conditions 
without any supplemental additives. The spray dried product was darker in 
color and exhibited very poor flow properties as compared to the above 
example with additives. Recovery of activity and solids were very 
satisfactory however, e.g. activity and solids recovery were 98% and 99% 
respectively. 
The spray dried product produced from concentrate without supplements 
required the addition of flow aids to prepare a useable product. 
Preparation of a useable product after storage of the spray dried material 
prepared from unsupplemented concentrate required both grinding and 
addition of flow aids. Loss in activity and solids accompanied these 
operations. Caking and lumping of the spray dried material prepared 
without additives occurred during storage for several months. 
EXAMPLE 5 
Neutral Bacterial Protease Concentrate 
This enzyme is prepared by growing a selected strain of Bacillus subtilis 
on a medium containing hominy, cornstarch and soybean meal under deep tank 
conditions to produce neutral bacterial protease. Activity is measured in 
terms of casein solubilization units (EE). The crude culture is filtered 
and washed using a rotary vacuum filter. The filtrate is concentrated by 
ultrafiltration and the concentrate is spray dried as described below. 
The crude culture, 113,000 pounds, containing neutral bacterial protease 
with a solids content of 12.8% and an activity of 1,330 EE was filtered 
and washed on a rotary vacuum filter to give 137,000 pounds of filtrate 
plus wash at 950 EE. Filtrate in the amount of 5,800 pounds (eqivalent to 
the use of 4,785 pounds of culture and 612 pounds of dry solids) was 
concentrated at 10.degree. C..+-.1.degree. C. in an ultrafilter unit to 
867 pounds of concentrate containing 11.2% solids and an activity of 6030 
EE. The dry solids in the ultrafilter concentrate (867 lbs.) amounted to 
97 pounds equivalent to about 16% of the solids present in the starting 
culture medium. 
One part of the concentrate (450 lbs.) was spray dried without any 
additives while the second part (417 lbs.) was treated with a mixture of 
13.9 pounds of cornstarch and 10.2 pounds of calcium phosphate added 
sequentially. The two parts of concentrate were spray dried separately in 
the same drier under the same conditions namely, 310.degree. 
F./170.degree. F. inlet/outlet air temperatures, atomized by centrifugal 
wheel of 160 mm turning at 18700 RPM. Table V below gives the results 
obtained from this experiment. 
TABLE V 
______________________________________ 
Concentrate without 
Concentrate with 
Supplementation 
Supplementation 
______________________________________ 
Dry solids 11.2% 16.0% 
Activity 6030 EE 5620 EE 
Pounds liquid 
concentrate dried 
450 441 
Pounds Spray dry 
Product 40.0 54 
Chamber Sweepings 
2.5 10 
Activity 
Product 49600 EE Product 28700 EE 
Sweepings 49600 EE Sweepings 30100 EE 
Recovery solids 
Product + 
Sweepings 84% 90.7% 
Activity recovery 
Product + 
Sweepings 77.7% 74.7% 
Physical Light Color Light Color 
Appearance of 
Good flow Good flow 
Spray Dried Became lumpy Retains good flow 
Product on storage in property on 
sealed container 
storage 
Moisture = 5.07 
= 4.78 
______________________________________ 
As noted this culture concentrate could be spray dried either with or 
without supplementation but the product caked up under storage unless the 
supplements were present at the time of spray drying. Addition of 
supplements after drying can be accomplished but in this case an added 
step of mixing is required and this must be accomplished before the spray 
dried material has caked. If caking occurs a grinding step is also 
necessary.