Transfer 20 grams of the pulp to an eight-ounce nursing bottle, nearly
filled with hot water, mix by shaking, and centrifuge until the
insoluble matter is collected in a cake in the bottom of the bottle.
Transfer the supernatant liquor onto a double, tared filter paper
covering the bottom of a Büchner funnel, using suction to facilitate
filtration.
Again fill the nursing bottle with hot water, stir the cake of
insoluble solids so that it is thoroughly mixed with the water,
centrifuge, and decant the supernatant liquor on the filter. Repeat
the centrifuging and the filtration of the supernatant liquor once
more, and then finally transfer the insoluble solids to the filter
paper and thoroughly wash with hot water. Dry the paper and insoluble
solids, and weigh. The insoluble solids are quite hydroscopic and the
weight must be taken quickly.