Eggleston G.,U.S. Department of Agriculture |
Viator R.,U.S. Department of Agriculture |
Gateuil A.,Agro Paris Technology Massy |
Fenger J.-A.,Agro Paris Technology Massy |
And 3 more authors.
International Sugar Journal | Year: 2013
There is a trend in the U.S. and world-wide to produce very high pol (VHP) and very low color (VLC) raw sugars for new refineries. This study was undertaken to ascertain the variations in juice quality parameters, known to affect VHP/VLC sugar manufacture and refining, across the LA 3-month processing season (late Sept to Dec) in 2009 and 2010. Juice was extracted from separated stalk (S), growing point region (GPR or immature apical internodes), green leaf (GL), and brown leaf (BL) tissues of three popular sugarcane varieties (HoCP 96-540, L 99-226 and L 99-233), five to six times between Sept and Dec. Except for the GPR tissue, as the sugarcane matured across the season there was a tendency for the pH of the tissue juices to became more acidic (P<.05), which is most likely detrimental to sucrose losses in late season. At some U.S. refineries, premiums for low color in sugar are paid on color measured at pH 8.5 whereas the rest of the world measures ICUMSA (International Commission for Uniform Methods in Sugar Analysis) color at pH 7.0. For both seasons, juice color at pH 8.5 accentuated varietal differences in juice color more than color at pH 7.0, and was more sensitive to GL colorants that contribute to the color of raw, VHP/VLC, and affined sugars. The highest per cent increase in color measured at pH 8.5 over color at pH 7.0 was observed for GL (av. 94.9 ± 0.3% std. dev.) and the lowest for BL (23.6 ± 3.1%); the values for GPR and stalk (S) tissue were 44.8 ± 3.2% and 64.3 ± 17.7, respectively. In those areas of the world where color (ICU) is measured at pH 7.0, the color of raw sugar may not always indicate all the colorants delivered to the refinery in raw sugar and those which need to be removed during the refining process. Except for stalk juice, the harvest date had a strong (P<.05) affect on tissue juice color measured at pH 8.5, and sugarcane variety also (P<.05) affected the juice color. Conductivity ash was highest in all tissues at the beginning of the season, decreased in the middle of the season then increased again to the end of the season.