DETERMINATION OF TOTAL QUANTITY OF CELL
WALL CONSTITUENTS IN FOODS AND FEEDS.

(Preliminary report.)

Lauri Paloheimo.

Zootechnical Institution, University Helsinki.

Received 15. 111. 1943.

The defectivness of the so called Weende-method for determining
of crude fibre is universally known. Altogether all attempts for
replacing this method with a more accurate one have remained
without success. The failure might be caused by the fact, that by
the proposed new methods the most essential defects of the old me-
thod have not been corrected.

The writer's aim was to build up a method for determining the
total quantity of plant cell wall constituents. The general principle
by his method consists in dissolving the cell enclosure carbohydrates
with very diluted acid. Before this procedure the matter should be
extracted with ether. The remainder after the treating with acid
consists of organic cell wall constituents together with some protein
and ash. The protein content of the residue may be estimated as
the difference of total crude protein of the matter and of the crude
protein of the filtrate after the acid treatment. The total quantity
of organic cell wall constituents is obtained as the difference: loss of
ignition minus protein of the residue.

The main features of the treatment with diluted acid are as
follows: I—21 —2 grams of the sampl are put in a beaker with about 350
cc. cold water. The mixture is warmed up to boiling temperature.
20 cc. 1-normal HCI solution is added and the volume of solution
completed to 400 cc. The duration of boiling should be 30 minutes.
Evaporated water is compensated during the boiling. A glass sinter
with a layer of quartz sand is employed by filtering.



20 LAURI PALOHEIMO

The concentration of acid solution suffices for the removal o
starch from the cells, but the lignins, cellulose and the main part o
hemicellulose remain unattacked. On the other hand it is likely
that pectins and gums are dissolved. In the writer's opinion it i:
not possible build up a method, by which the total of the cell wal
constituents can be accurately determined: either a part of enclosun
substances remains in cells or a part of the cell wall constituents art
dissolved. The above described method, however, leads rather neai
the set aim, even though the first word of the expression »total o
cell wall constituents» may not be proved quite exact, when the tern
is used in that meaning as in this treatise.

Total of cell wall Cmdefibrconstituents by the Weende
>

the writer s ~ ~
method) meth

°d )

% of dry matter

Spruce wood 90.9 73.8
Birch wood 90.8 59.5
Cork 85.1 22.3
Peat litter 85.1 42.9
Rye straw 82.1 51.1
Oat straw 73.8 47.0
Oat hulls 71.0 34.1
Rye chaff 66.8 34.3
Timothy hay 62.1 32.8
Timothy grass, pasture stage 50.3 22.6
Red clover leaves 30.7 18.2
Wheat bran 21.5 9.1
Spinach 18.0 9.9
Mushrooms (Boletus bulbosus) 17.2 11.5
Cabbage, head, without stem 14.0 12.fi
Carrots ' 12.8 10.0
Rutabagas (Br. napus napobrassica), peeled . . 12.7 10.8
Apples, peeled 6.3 5.1
Wheat flour, Graham 5.0 3.0
Potatoes, peeled 3.9 3.0
Wheat flour, white 0.7 0.3

Some figures from our investigations are exhibited in the enclosed
table. It seems obvious, that the nutritive qualification of the in-
vestigated materials finds by the new method a considerable clearer
expression than by the old Weende-method.



DETERMINATION OF CELL WALL CONSTITUENTS 21

SELOSTUS.

KETTOAINEIDEN MÄÄRITTÄMINEN RUOKA- JA REHUAINEISTA

Lauri Paloheimo.

Yliopiston Kotieläintieteellinen laitos, Helsinki.

Raakakuitumääritys ehdotetaan korvattavaksi kettoaineiden kokonaispaljouden
määrittämisellä. Menetelmä perustuu solusisällysaineiden ryhmään kuuluvien hiili-
hydraattien poistamiseen keittämällä näytettä 0.05 normaalisessa suolahappoliuoksessa.