Production techniques of leaf protein concentrate from sweet cassava (Manihot esculenta) and its nutritional value for Nile tilapia (Oreochromis niloticus)
1992
Widyatmoko
Production techniques of leaf protein concentrate (LPC) from sweet cassava were evaluated. Two machines, namely hammermill and shredder were tested to macerate leaves. Relationship of pressure and percentage of added water in juice production was evaluated using Instron instrument. A vertical screw press was tested to extract juice and dry matter from macerated leaves with different loading rate and pressing frequency. Extracted juice was treated differently, by acid and heat treatment, to precipitate the protein content. The yield was compared to untreated juice (spontaneous precipitation). Nutritional value of the leaf protein extract and its residual were evaluated as fish meal substitute in complete diet for Nile tilapia. Hammermill consumed less energy and more simple in operation than shredder. Energy consumption was 1.88 kWh/kg and 0.33 kWh/kg for shredder and hammermill, respectively. Moisture content of the macerated leaves was not affected by additional of water. Extracted juice increased by adding water at the rate of 0 % (control), 50, 100, 150, 200, and 250 % of sample weight with total juice production at the amount of 17.7, 62.0, 120.9, 142.8, 224.2, and 275.2 g, respectively. The same treatments of added water produce dry matter at the amount of 0.42, 2.49, 4.00, 5.04, 4.49, and 3.66 g, respectively; with dry matter recovery were 1.97, 11.82, 18.74, 23.82, 21.21, and 17.17 %, respectively. More than 50 % of the juice was extracted by 50 kg pressure, except for control. At higher pressure level weight of juice extracted was lower. Dry matter (DM) 'production' and DM recovery increased considerably by double pressing of screw press. DM production and DM recovery increase more than two times by double pressing for 2.0 kg loading rate.
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