6 BULLETIN 1194, U. S. DEPARTMENT OF AGRICULTURE. 
the sugar of the pods and material with a high content of protein 
would be secured. The milling process to which the dried fruit was 
subjected was somewhat similar to the milling received by wheat in 
making flour. 
Table 1 summarizes the analytical data 6 thus obtained. 
Table 1. — Composition of dried mesquite fruit separated by experimental milling. 
Sam- 
ple 
No. 
Material analyzed. 
Mois- 
ture. 
Ether 
Crude 
Ash. 
ex- 
pro- 
tract. 
tein. 
P.ct. 
P.ct. 
P.ct. 
3.6 
0.9 
5.1 
3.7 
2.0 
17.1 
5.0 
2.6 
12.8 
4.5 
1.9 
11.6 
Nitro- 
Cmde tee" 
fiber - ex- 
tract. 
Re- 
duc- 
ing 
sugars 
as in- 
vert. 
Su- 
crose. 
Galac- 
tans. 
29973 
Coarse separation, largely seed P. ct. 
husks 6. 6 
Coarser portion of second sepa- 
ration, containing much seed 
material 6. 7 
Fine separation, high in sugar 
material ". . . . 5. 8 
29972 Whole fruit, ground 6.9 
29975 
29976 
P. ct. P. ct. 
42.6 41.2 
23.4 
16.2 
23.9 
47.1 
57.6 
51.2 
P.ct. 
0.43 
.09 
.04 
P.ct. 
7.74 
15.30 
31.66 
P.ct. 
8.71 
1.61 
1.86 
The protein and sugar results show that the separations were very 
imperfect. Batches of ground, dried fruit were prepared later, under 
the supervision of the San Antonio Chamber of Commerce, especially 
for the purpose of determining whether or not it would be practicable 
to gather the fruit when still slightly green or whether it would be 
necessary to allow it to fully mature on the tree. The composition of 
material of these two types is given in Table 2. Sample 30178 repre- 
sents the slightly immature sun-dried fruit, and sample 30179 the 
fully matured fruit. Except for a somewhat higher sugar content in 
the fruit picked just before maturity and sun dried, there appears to 
be no significant difference in composition between the two lots. 
An effort was made to prepare sugar (sucrose), or at least an edible 
sirup, from sample 30179. Neither could be obtained from ground 
whole fruit by any process which would lend itself to commercial use, 
owing probably to the presence of the protein of the seeds. By 
elaborate purification of a water extract of mesquite pod material, 
crystalline sucrose (cane sugar) was prepared and identified by 
crystallographic criteria. The method of purification used would not 
be practicable on a commercial scale. Many years ago Steel {21) 
identified the principal sugar of the mesquite pod as sucrose. 
If sugar ever is to be prepared from mesquite, the first step in the 
process of manufacture must be a fairly clean separation of seed 
material from pod and husk material. Part of the experimental work 
of the Arizona station '(7) therefore was repeated. A representative 
sample of second crop fruit (sample 32869), composed of mature fruit, 
but slightly below average in quality because of a wet season (PI. II, 
fig. 1) , was separated by hand into pod material, husks or seed capsules, 
seed coats, and seed kernels. The beans had been picked on August 29 
and when harvested had a moisture content of over 31 per cent. The 
composition of this fruit, calculated to the air-dry and moisture-free 
bases, is shown in Table 2. 
« The methods of chemical analysis used throughout this work are those of the Association of Official 
Agricultural Chemists, or such slight modifications of the official methods as are best adapted to material 
like mesquite beans. The Bryan-Given-Straughn alcohol-extraction method was used in the sugar deter- 
minations. 
