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(2 Points) 1000 kg of soybeans, of composition 18% oil, 35% protein, 27.1% carbo

ID: 1882698 • Letter: #

Question

(2 Points) 1000 kg of soybeans, of composition 18% oil, 35% protein, 27.1% carbohydrate. 9.4%, fiber/ash, 10.5% moisture, are: (a) crushed and pressed, which reduces oil content in beans to 6%; (b) then the pressed soy is extracted with hexane to produce a meal containing 0.5% oil; (c) finally the meal is dried to 8% moisture. Assuming that there is no loss of water with the oil, or loss of protein, carbohydrate and fiber/ash in any step of the process, what is the composition of the final dried meal?

Explanation / Answer

Mass in:
Oil       = 1000 x 18/100    = 180 kg
Protein = 1000 x 35/100 = 350 kg
Total non-oil constituents = 820 kg

Carbohydrate, ash, fibre and water are calculated in a similar manner to fat and protein.

Mass out:
(a) Expressed oil.
In original beans, 820kg of protein, water, etc., are associated with 180 kg of oil.
In pressed material, 94 parts of the protein, water, etc., are associated with 6 parts of oil.
Total oil in expressed material 820 x 6/94 = 52.3 kg.
Oil extracted in press    = 180 - 52.3        = 127.7 kg.

(b) Extracted oil.
In extracted meal 99.5 parts of protein, water, etc., are associated with 0.5 parts of oil.
Total oil in extracted meal = 820 x 0.5/99.5 = 4.1 kg.
Oil extracted in hexane    =    52.3 - 4.1      = 48.2 kg.

(c) Water.
In the dried meal, 8 parts of water are associated with 92 parts of oil, protein, etc.
Weights of dry materials in final meal = 350 + 271 + 94 + 4.1 = 719.1 kg.
Total water in dried meal                   = 719.1 x 8/92 = 62.5 kg.
Water loss in drying                         = 105 - 62.5     = 42.5 kg.

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