ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

AppendixB
DETAILS OF MEmOOOLOGY
BA1 Proximate analysis (AOAC, 1990)
BA1.1 Ash determination
Volatile organic matter was driven off when 2.5 g of the sample was ignited and kept at
600 0 C for six homs in an electric furnace. The residue was quantitated and the mass ofthe
inorganic matter over the mass ofthe organic matter was noted as percentage ash.
BA1.2 Moisture determination
50 g ofthe sample was transferred to previously weighed and dried crucibles, then dried in
a thermostatically controlled oven at 1l0° C for 24 hOUTS. Samples were then removed,
cooled in desiccators and weighed. The final weight over the initial weight was recorded as
the percentage ofmoisture.
BAl.3 Crude fat determination
0.5 g of dry samples was pre-extracted with 25 ml ofpetroleum ether for 50 minutes with
an automatic soxhlet system (Soxtec HT-6, Tacater AB, Hoganas). The solvent in the
extraction cups was evaporated overnight in an oven (70 0
fat percentage.
BAl.4 Soluble carbohydrate determination [Hansen and Meller (1975)]
C) and weighed to calculate the
Extraction and determination of soluble carbohydrates were performed according to the
methods of Hansen and Maller (1975). One gram of each sample was quantitatively
transferred into bmettes stuffed with glass wool. These bmettes had been previously set up
as shown in Figure B-1. The samples were wet with 2 ml of 80 per cent ethanol each and
stirred to remove air bubbles in order to avoid channel formation.
242