Submitted to: Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/12/2002
Publication Date: 1/10/2003
Citation: Eggleston, G., Legendre, B. 2003. Mannitol and oligosaccharides as new criteria for determining cold tolerance in sugarcane varieties. Food Chemistry. 80(4):451-461. Interpretive Summary: Freeze deterioration of sugar cane before harvesting can cause problems in factory processing leading to high sucrose and dollar losses. Present methods to measure cold tolerance or freeze deterioration in cane are not very sensitive, too time consuming, or expensive. In this study, new and more sensitive indicators of cane freeze deterioration of cane were found. A compound called mannitol was identified as a very sensitive indicator of cane deterioration in the U.S. which will help predict future factory processing problems.
Technical Abstract: Freeze deteriorated cane can cause problems in processing. This study was undertaken during the 2000/2001 harvest season to assess the cold tolerance performance of six commercial sugarcane varieties and to establish new and more sensitive criteria to measure cold tolerance. Freezing temperatures occurred on Dec 20, 2000, and again on Dec 21, Dec 30 through Jan 5, 2001, Jan 9-10 and Jan 20-21. Stalks of all varieties were frozen to the ground following the initial freeze with freeze cracks evident only after the Jan 4 freeze. Samples were taken on the date of the first freeze (0 days)and 7, 14, 22 and 30 days afterwards. Criteria used to measure overall stalk cold tolerance included changes in pH, dextran (ASI-II method), sucrose, glucose, and fructose concentrations. Mannitol, ethanol and the oligosaccharides palatinose, leucrose, isomaltotriose and 1-kestose were simultaneuously measured using IC-IPAD. Mannitol was strongly correlated (r*2=.84) with dextran confirming its use as an indicator for cane dextran deterioration. In comparison, ethanol was only weakly correlated (r*2=.55) with dextran and did not always predict cane dextran deterioration. Isomaltotriose was the best oligosaccharide indicator of freeze deterioration, and pH was also a strong indicator of both dextran (r*2=-0.85) and mannitol (r*2=-.92) formation. Four varieties were shown to be susceptible to other sources of microbial and enzymic deterioration as well as dextran deterioration, especially 30 days after the first freeze.