Lynne Wong's PhD thesis

2.1.3 Methodology
A mass of 2 kg each of dry trash, green leaves and immature cane tops without attached
foliage above the natural breaking point of cane stalk, were shredded separately in a Jeffco
cutter-grinder (Fig 2.1). Subsequently 20 kg of clean cane stalks, which had previously
been chipped coarsely in a cane chipper (Fig 2.2), were shredded. The finely divided clean
cane was well mixed; a sub-sample of 1329 g was taken, 329 g of which was analysed for
pol % cane and fibre % cane by the Société de Technologie Agricole et Sucrière de
Maurice (STASM) method (Anon., 1991). Simultaneously, one kg of the clean cane was
subjected to a pressure of 20 MPa (200 bar) for two minutes in a Pinette Emidecau
hydraulic press (Fig 2.3) to obtain first expressed juice. Distilled water (330 mL) was
sprayed onto the pressed cake and a second pressing carried out to obtain “mixed juice”.
The mass of the cake was weighed as bagasse, of which 50 g were analysed for moisture
content and 150 g for Brix and pol (for method, see Appendix 1). Fibre % bagasse was
taken as 100 – moisture % bagasse – Brix % bagasse. Mercuric iodide juice preservative
was added to the mixed juice at the rate of 0.5 mL L -1 before analysis for Brix by a
refractometer (Fig 2.4), pol and Clerget sucrose by a polarimeter (Fig 2.5) by the STASM
method (Anon., 1991), sulfated ash content (for method, see Appendix 2), and glucose,
fructose and sucrose by high performance ion chromatography making use of the official
International Commission for Uniform Methods of Sugar Analysis (ICUMSA) method for
molasses modified for juices (Schäffler, 1994) using lactose as internal standard. Clerget
purity was obtained by dividing Clerget sucrose by the Brix, expressed as a percentage.
The experiment was repeated with shredded dry trash, green leaves and cane tops added
separately to sub-samples of the shredded clean cane so that the added EM constituted 5%,
10% and 20% of the total mass which was 1329 g. The experiment was concluded with a
second sub-sample of clean cane alone, to ascertain that no deterioration of the cane had
occurred. This was assessed by ensuring that the pol of the second mixed juice was not
less than 0.05% lower than the first one, and the average of the two sets of clean cane data
was taken. As an indication, the eleven “mixed juice” samples were processed not later
than two hours after the start of the experiment. The composition in terms of moisture,
Brix and pol of shredded dry trash, green leaves and cane tops were determined as for
bagasse (Appendix 1).
Six trials were carried out on fresh supply of cane and EM.
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